This file was created by the Typo3 extension sevenpack version 0.7.14 --- Timezone: CEST Creation date: 2013-06-20 Creation time: 10-51-22 --- Number of references 138 article Kirschfeld2012 Laborjournal 2012 4 2012 4 14-18 Wer sich einer Katarakt-Operation unterzieht, hofft auf klare Sicht durch ein Implantat. Dabei werden auch Linsen mit mehreren Brennweiten empfohlen, ihre Nachteile jedoch nicht erklärt. Kuno Kirschfeld, emeritierter Direktor am Max-Planck-Institut für biologische Kybernetik Tübingen, hält die Multifokallinsen nicht immer für die beste Wahl (siehe auch Ophthalmologe 2011, 108(12):1139-44). http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2012/Laborjournal-2012-Kirschfeld.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld kunoKKirschfeld article KirschfeldL2011 Ophthalmologe 2011 12 108 12 1139-1144 Fortschritte in der Intraokularlinsentechnologie haben dazu geführt, dass bei Kataraktoperationen immer häufiger moderne Multifokallinsen ins Auge eingesetzt werden. Die in der Literatur geäußerten Vorstellungen über die Wirkungsweise dieser Linsen sind zum Teil aber unzutreffend. Wir stellen die Grenzen der Leistungsfähigkeit dieser Linsen dar und zeigen, dass monofokale Intraokularlinsen, bei Bedarf ergänzt durch eine Brille, eine höhere Sehschärfe ermöglichen. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/2011/Ophtalmologe-2011-Kirschfeld.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld 10.1007/s00347-011-2462-2 kunoKKirschfeld M-FLand article 6210 Gehirn und Geist, Apropos 2009 7 2009 6 1-5 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/DasManifest5Jahredanach_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.gehirn-und-geist.de/artikel/1001695&amp;_z=798884 Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld article 6211 Zoologie 2009 2009 51-55 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Zoologie-2009-51_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld PKunze article 5278 Neuroreport 2008 6 19 9 907-910 The amplitude of [alpha] waves in an ongoing electroencephalogram can be reduced by visual stimuli and by attention. We reduced [alpha] amplitudes by presenting a short visual stimulus in the visual periphery, 10[degrees] apart from the fovea, and measured (i) the decrease of [alpha] amplitudes as a function of time and (ii) delays in reaction to foveal stimuli presented at various intervals after the peripheral stimulus. It turned out that in the time window from 0 to 2 s after the peripheral stimulus, both responses decrease in parallel with a minimum at 350-500 ms. The close correspondence between [alpha] amplitude and reaction time supports the view that [alpha] waves are functionally relevant for this behaviour. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://ovidsp.ovid.com/ovidweb.cgi?T=JS&amp;NEWS=N&amp;PAGE=fulltext&amp;AN=00001756-200806110-00002&amp;LSLINK=80&amp;D=ovft Biologische Kybernetik Max-Planck-Gesellschaft en 10.1097/WNR.0b013e328302c545 kunoKKirschfeld article 5028 Deutsches Ärzteblatt International 2008 1 105 3 53 The authors propose the use of alpha-blockers and 5 alpha-reductase inhibitors for the management of benign prostatic syndrome. As another group of substances for therapeutic use, I would suggest secretolytics and mucolytics. The prostate of elderly men often contains leukocyte permeated secretion masses in dilated glandular ducts (1). Mucoproteins are one of the constituents of prostatic secretion. In addition, the tissue pressure of the prostate is significantly increased in patients with chronic abacterial prostatitis (2). Elevated tissue pressure might conceivably be causally implicated in the pain associated with this condition. Mucoproteins are a constituent of prostatic secretion, and mucolytics could reduce the elevated tissue pressure. Mucoproteins contain disulfide bonds that can be cleaved by the free sulfhydryl group, for instance of the mucolytic agent acetylcysteine. In saliva, glycoproteins are depolymerized by cleavage of the disulfide bridges, which reduces the viscosity of the sputum. Should it also be possible to lower the viscosity of prostatic secretion by depolymerization of various components, outflow could be improved. After many years of suffering considerable symptoms of abacterial prostatitis, I took 2 x 600 mg ACC as a self-experiment. The symptoms improved within two hours and symptom remission was complete after two days. The PSA value normalized simultaneously (for details see my list of references: www.kyb.mpg.de). Secretolytics/mucolytics could conceivably also improve the symptoms of benign prostatic syndrome. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.aerzteblatt.de/v4/archiv/pdf.asp?id=58639 Biologische Kybernetik Max-Planck-Gesellschaft de 10.3238/arztebl.2008.0053a kunoKKirschfeld article 5612 Deutsches Ärzteblatt 2008 1 105 3 53 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/LeserbriefÄBL_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.aerzteblatt.de/v4/archiv/pdf.asp?id=58624 Biologische Kybernetik Max-Planck-Gesellschaft de 10.3238/arztebl.2008.0053a kunoKKirschfeld article 4714 Laborjournal 2007 3 2007 3 14-18 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Laborjournal-2007-14_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de SBär kunoKKirschfeld article 4765 Der Urologe 2006 11 1-3 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/LeserbriefUrologe_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld article 3602 Vision Research 2006 4 46 8-9 1547-1551 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/VisRes_Kirschfeld_Stopping%20motion%20and%20the%20flash-lag%20effect_3602[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T0W-4GYNY0B-2-7&_cdi=4873&_user=29041&_orig=browse&_coverDate=04%2F30%2F2006&_sk=999539991&view=c&wchp=dGLzVzz-zSkWb&md5=c6172fb1d9eb3e57de412d9885b92ab2&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/j.visres.2005.07.010 kunoKKirschfeld article 4408 Der Urologe 2006 1 1-8 No effective management of chronic, nonbacterial prostatitits is as yet available. Here a case is reported in which a new therapy successfully was applied: oral application of mucolytica, with the intention to reduce viscosity of fluids in prostatic tissue and ducts and hence facilitating their efflux. Tissue pressure may decrease and consequently painful sensations also. In the case documented acetylcystein was the mucolytical substance. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/Kirschfeld-Urologe-2006_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld article 3601 Biological Cybernetics 2005 2 92 3 177-185 Synchronised activity, differing in phase in different populations of neurons, plays an important role in existing theories on the function of brain oscillations (e.g., temporal correlation hypothesis). A prerequisite for this synchronisation is that stimuli are capable of affecting (resetting) the phase of brain oscillations. Such a change in the phase of brain waves is also assumed to underlie the ldquoBerger effectrdquo: when observers open their eyes, the amplitude of EEG oscillations in the alpha band (8–13 Hz) decreases significantly. This finding is usually thought to involve a desynchronisation of activity in different neurons. For functional interpretations of brain oscillations in the visual system, it therefore seems to be crucial to find out whether or not the phase of brain oscillations can be affected by visual stimuli. To answer this question, we investigated whether alpha waves are generated by a linear or a nonlinear mechanism. If the mechanism is linear – in contrast to nonlinear ones – phases cannot be reset by a stimulus. It is shown that alpha-wave activity in the EEG comprises both linear and nonlinear components. The generation of alpha waves basically is a linear process and flash-evoked potentials are superimposed on ongoing alpha waves without resetting their phase. One nonlinear component is due to light adaptation, which contributes to the Berger effect. The results call into question theories about brain-wave function based on temporal correlation or event-related desynchronisation. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/The%20physical%20bases%20of%20alpha%20waves_Bio%20Cyb_3601[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.springerlink.com/content/kpgjhupptyd9dytk/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1007/s00422-005-0547-1 kunoKKirschfeld article 4407 World Journal of Urology 2005 1-7 No effective management of chronic, nonbacterial prostatitits is as yet available. Here a case is reported in which a new therapy successfully has been applied: oral application of mucolytica, with the intention to reduce viscosity of fluids in prostatic tissue and ducts and hence facilitating their efflux. Tissue pressure may decrease and consequently painful sensations also. In the case documented acetylcystein was the mucolytical substance. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/KirschfeldMucolytica_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld article 1178 Zoology 2004 11 104 3-4 256-267 Over the course of the last 50 years it has been possible to solve a number of basic problems in neurobiology. Interest is now turning more and more to problems concerning so-called “higher&#961; brain functions, including cognition. Examples from the visual system in primates are presented. First relatively elementary problems are illustrated, such as how long it takes to perceive an object or to respond to a stimulus or combinations of stimuli. Top-down modification of perception by expectation is demonstrated in an illusion of misdirected gaze. Interdisciplinary questions straddling the sciences and the humanities are also approached, such as which part of the brain mediates conscious perception. Finally, the problem of causality and freedom of will is addressed, taking into account the knowledge accumulated in the neurosciences during the last 5 decades. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B7GJ0-4DR7GW8-12-1&_cdi=20192&_user=29041&_orig=search&_coverDate=01%2F01%2F2001&_sk=998959996&view=c&wchp=dGLbVzW-zSkzV&md5=2ecc7528df5bbe9f182e693d20f9b474&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1078/0944-2006-00031 kunoKKirschfeld article 3228 Current Biology 2003 4 13 9 749-753 Motor behaviors require animals to coordinate neural activity across different areas within their motor system. In particular, the significant processing delays within the motor system must somehow be compensated for. Internal models of the motor system [1], in particular the forward model [2 and 3], have emerged as important potential mechanisms for compensation. For motor responses directed at moving visual objects, there is, additionally, a problem of delays within the sensory pathways carrying crucial position information. The visual phenomenon known as the flash-lag effect has led to a motion-extrapolation model for compensation of sensory delays [4, 5 and 6]. In the flash-lag effect, observers see a flashed item colocalized with a moving item as lagging behind the moving item. Here, we explore the possibility that the internal forward model and the motion-extrapolation model are analogous mechanisms compensating for neural delays in the motor and the visual system, respectively. In total darkness, obser vers moved their right hand gripping a rod while a visual flash was presented at various positions in relation to the rod. When the flash was aligned with the rod, observers perceived it in a position lagging behind the instantaneous felt position of the invisible rod. These results suggest that compensation of neural delays for time-varying motor behavior parallels compensation of delays for time-varying visual stimulation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science?_ob=MImg&amp;_imagekey=B6VRT-48GV9DX-T-7&amp;_cdi=6243&amp;_user=29041&amp;_orig=browse&amp;_coverDate=04%2F29%2F2003&amp;_sk=999869990&amp;view=c&amp;wchp=dGLbVlz-zSkzk&amp;md5=c7ecee23c42ee70473b1bbc38f23482a&amp;ie= Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/S0960-9822(03)00248-3 RNijhawan kunoKKirschfeld article 73 Anästhesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie 2000 12 35 12 731-743 Positron emission tomography studies on volunteers showed that, at concentrations inducing the loss of consciousness, propofol, halothane and isoflurane reduce glucose metabolism of neocortical neurones by 20-50%. To find out whether these effects are caused by direct anaesthetic actions on cortical structures, experiments were carried out on isolated neocortical brain slices. In these investigations an excellent correlation was observed between anaesthetic concentrations causing a half-maximal depression of action potential firing in neocortical brain slices and anaesthetic blood concentrations monitored during awaking from anaesthesia in humans. Furthermore, it could be shown that, at concentrations approximately one half the MAC-value, isoflurance decreases the frequency of auditory evoked 30-40 Hz oscillations in the neocortex by 50%. Similar quantitative effects were observed on spontaneously occurring high frequency rhythms in neocortical brain slices. However, not all aspects of cerebral anaesthetic actions can be explained by direct effects on cortical neurones. The EEG synchronisation and the amplitude reduction of mid latency auditory evoked potentials are probably related to the inhibition of thalamic neurones. Halothane, isoflurance, enflurance and propofol reduced action potential firing of cortical neurones by enhancing GABAA receptor-mediated synaptic inhibition. This molecular mechanism seems also to be involved in depressing painful stimuli-induced motor responses. Nevertheless, there must be a difference between relevant anaesthetic mechanisms on the cerebral and spinal level. This follows from the observation that the relation between the concentration causing the loss of consciousness and the concentration that depresses movements considerably varies among different anaesthetic agents. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de antkowiaBAntkowiak kunoKKirschfeld article 71 Journal of Neuroscience 2000 8 20 15 5748-5755 Drosophila transient receptor potential (TRP) is a prototypical member of a novel family of channel proteins underlying phosphoinositide-mediated Ca2+ entry. Although the initial stages of this signaling cascade are well known, downstream events leading to the opening of the TRP channels are still obscure. In the present study we applied patch-clamp whole-cell recordings and measurements of Ca2+ concentration by ion-selective microelectrodes in eyes of normal and mutant Drosophilato isolate the TRP and TRP-like (TRPL)-dependent currents. We report that anoxia rapidly and reversibly depolarizes the photoreceptors and induces Ca2+ influx into these cells in the dark. We further show that openings of the light-sensitive channels, which mediate these effects, can be obtained by mitochondrial uncouplers or by depletion of ATP in photoreceptor cells, whereas the effects of illumination and all forms of metabolic stress were additive. Effects similar to those found in wild-type flies were also found in mutants with strong defects in rhodopsin, Gq-protein, or phospholipase C, thus indicating that the metabolic stress operates at a late stage of the phototransduction cascade. Genetic elimination of both TRP and TRPL channels prevented the effects of anoxia, mitochondrial uncouplers, and depletion of ATP, thus demonstrating that the TRP and TRPL channels are specific targets of metabolic stress. These results shed new light on the properties of the TRP and TRPL channels by showing that a constitutive ATP-dependent process is required to keep these channels closed in the dark, a requirement that would make them sensitive to metabolic stress. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.jneurosci.org/content/20/15/5748.long Biologische Kybernetik Max-Planck-Gesellschaft KAgam Mvon Campenhausen SLevy HCBen-Ami BCook kunoKKirschfeld BMinke article 100 Journal of Comparative Physiology A 2000 6 186 6 583-593 In experiments described in the literature objects presented to restrained goldfish failed to induce eye movements like fixation and/or tracking. We show here that eye movements can be induced only if the background (visual surround) is not stationary relative to the fish but moving. We investigated the influence of background motion on eye movements in the range of angular velocities of 5–20° s−1. The response to presentation of an object is a transient shift in mean horizontal eye position which lasts for some 10 s. If an object is presented in front of the fish the eyes move in a direction such that it is seen more or less symmetrically by both eyes. If it is presented at ±70° from the fish's long axis the eye on the side of the object moves in the direction that the object falls more centrally on its retina. During these object induced eye responses the typical optokinetic nystagmus of amplitude of some 5° with alternating fast and slow phases is maintained, and the eye velocity during the slow phase is not modified by presentation of the object. Presenting an object in front of stationary or moving backgrounds leads to transient suppression of respiration which shows habituation to repeated object presentations. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2Fs003590050010 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/s003590050010 SSchaerer kunoKKirschfeld article 90 Vision Research 2000 4 40 9 1027-1033 In human observers, cue-induced visual attention (&lsquo;bottom-up&lsquo; transient focal attention) shortens the latency of perception. Metacontrast reduces the intensity of perception and can even obliterate it. We show that a close relationship exists between both, but that their effects are reversed: cue-induced visual attention not only shortens latency but also intensifies perception, and metacontrast not only lowers intensity of perception but also prolongs latency. A common neurophysiological mechanism for both is possible. Indirect evidence suggests that this could be a subthreshold modulation of neuronal thresholds by de- and hyperpolarization. (C) 2000 Elsevier Science Ltd. All rights reserved. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6T0W-3YWWYMX-1-F&_cdi=4873&_user=29041&_orig=browse&_coverDate=04%2F30%2F2000&_sk=999599990&view=c&wchp=dGLbVtb-zSkzV&md5=b75451d15fc097c15841e8319d9f7c8c&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1016/S0042-6989(00)00040-7 kunoKKirschfeld kammerTKammer article 89 Naturwissenschaftliche Rundschau 2000 3 53 3 117-130 Eine ganze Reihe von Grundfragen der Neurowissenschaften konnte in der zweiten Hälfte dieses Jahrhunderts gelöst werden: wie ein physikalischer Reiz in ein körpereigenes Signal umgesetzt wird (Transduktion), wie Signale im Nervensystem weitergeleitet werden (Nervenleitung), wie Signale von einer Nervenzelle zur nächsten übertragen werden (Synapsenfunktion). Weitere Grundfragen, zum Beispiel die nach der Repräsentation von Objekten im Gehirn, werden intensiv erforscht; Teilaspekte sind bereits gelöst. Damit werden Probleme unter einem neuen Blickwinkel diskutierbar, die dem psychophysischen Grundproblem zuzuordnen sind, und die bis vor nicht allzu langer Zeit als unbeantwortbar galten: Welche Teile des Gehirns vermitteln bewusste Wahrnehmung? Widersprechen sich Kausalgesetz und Willensfreiheit? Müssen moralische Entscheidungen bewusst erfolgen? Gibt es einen grundsätzlichen Unterschied zwischen nicht erklärbaren Phänomenen der Physik und nicht erklärbaren Phänomenen des Bewusstseins? Im ersten Teil der Arbeit werden einige Ergebnisse der Hirnforschung dargestellt, im zweiten Grenzfragen zur Philosophie diskutiert. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld article 3715 Neuroforum 2000 3 2000 1 141-148 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld article 199 Consciousness and Cognition 1999 12 8 4 462-483 Our visual system not only mediates information about the visual environment but is capable of generating pictures of nonexistent worlds: afterimages, illusions, phosphenes, etc. We are “aware” of these pictures just as we are aware of the images of natural, physical objects. This raises the question: is the neural correlate of consciousness (NCC) of such images the same as that of images of physical objects? Images of natural objects have some properties in common with afterimages (e.g., stability of verticality) but there are also obvious differences (e.g., images maintain size constancy, whereas afterimages follow Emmert&lsquo;s Law: when seen while screens at different distances are observed, an afterimage looks larger, the greater the distance of the screen). The differences can be explained by differences in the retinal extent of images and afterimages, which favors the view that both have the same NCC. It seems reasonable to assume that before neural activity can produce awareness, all the computations necessary for a veridical representation of, e.g., an object, must be completed within the neural substrate and that information characteristic of a particular object must be available within the NCC. Given these assumptions, it can be shown that no retinotopic (in a strict sense) cortical areas can serve as the NCC, although some type of topographic representation is necessary. It seems also to be unlikely that neurons classified as cardinal cells alone can serve as NCC. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WD0-45GWB2J-5-1&_cdi=6752&_user=29041&_orig=browse&_coverDate=12%2F31%2F1999&_sk=999919995&view=c&wchp=dGLbVlb-zSkzS&md5=f938eae136cd39bf49139b38feac4932&ie=/sdarticle.pdf Biologische Kybernetik Max-Planck-Gesellschaft en 10.1006/ccog.1999.0388 kunoKKirschfeld article 460 Vision Research 1999 11 39 22 3702-3709 Usually we assume that the central nervous system preserves temporal sequences. Here we show that moving objects—in the context of behaviour often dangerous ones—are seen with a shorter latency than stationary (flashed) objects. In addition moving objects are deblurred. Two mechanisms contribute to this functional specialisation: cue-induced visual focal attention and metacontrast. Under unnatural conditions these mechanisms lead to an optical illusion first described by Fröhlich [Fröhlich, F. W. (1923). Über die Messung der Empfindungszeit. Zeitschrift für Sinnesphysiologie, 54, 58–78]. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/S0042698999000899 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/S0042-6989(99)00089-9 kunoKKirschfeld kammerTKammer article 182 Vision Research 1999 4 39 8 1551-1554 If we look out of the window of a travelling train our eyes move rapidly back and forth (saccadic movement). With no attention to individual objects, gaze velocity is low but nystagmic frequency is high (stare nystagmus). If we are interested in individual objects, the angular velocity of gaze is high and the nystagmic frequency low (look nystagmus) (Ter Braak, J.W.G. (1936). Untersuchungen ueber optokinetischen Nystagmus. Archives Néerlandaises de Physiologie de L’homme et des Animaux, 21, 309–376) We show that the spectral sensitivities of the two types of nystagmus differ and that the short-wavelength-sensitive cones significantly contribute only to look nystagmus. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/S0042698998002120 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/S0042-6989(98)00212-0 MVCampenhausen kunoKKirschfeld article 198 Neuroscience Letters 1999 3 263 2-3 133-136 Increasing the intensity of a stimulus such as luminance results in faster processing of the signal and therefore decreases simple motor reaction time (RT). We studied the latencies of visual evoked potentials (VEPs, N80, P100, N130) and RTs in eight subjects to flashing spots of light while varying the luminance of the spots from 1 to 1000 cd/m(2). The data show that processing time as a function of intensity is modified not only at the retina but also at later processing sites. This indicates a temporal dispersion of the Visual signal over the whole processing stream from visual input all the way to motor output. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/pdf198.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/S0304394099001378 Biologische Kybernetik Max-Planck-Gesellschaft 1016/S0304-3940(99)00137-8 kammerTKammer lehrLLehr kunoKKirschfeld article 234 Biological Cybernetics 1998 11 79 6 443-444 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2Fs004220050493 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/s004220050493 GHauske kunoKKirschfeld article 1312 Journal of Comparative Physiology A 1998 7 163 4 421-423 A method is described that allows the spectral sensitivity of photoreceptors to be measured with high spectral resolution. It is shown that the sensitivity of the ocelli ofMusca andCalliphora has a vibrational fine structure in the ultraviolet, strongly indicative of a sensitizing pigment. The visual pigment has its absorption maximum close to 425 nm. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00604896 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00604896 kunoKKirschfeld feilerRFeiler KVogt article 149 Journal of Comparative Physiology A 1998 6 183 1 1-6 When an animal is moving relative to its surroundings it can nevertheless stabilize the image on the retina, at least partially, by means of the large-held optomotor response. In the animal species investigated so far, this response has been found to be colour-blind as indicated by grey-matching tests, and to involve only photoreceptors sensitive in the long- wavelength region of the spectrum. Here we show that this rule also applies to pigeons, i.e. birds, a group not previously studied in this regard. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2Fs003590050229 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/s003590050229 MVCampenhausen kunoKKirschfeld article 352 British Journal of Anaesthesia 1997 11 79 5 617-624 We have investigated in rat brain slices the effects of the volatile anaesthetics enflurane, isoflurane and halothane on spontaneous discharge patterns and mean firing rates of cerebellar Purkinje cells. In the absence of these anaesthetics, Purkinje cells fired bursts of action potentials separated by quiescent periods lasting less than 2 s. Mean discharge rates were 10.8 (SEM 0.4) Hz at 23 +/- 1 degrees C and 25.6 (1.2) Hz at 35 +/- 1 degrees C. The agents exhibited qualitatively different effects when applied at concentrations corresponding to 1-3 MAC. Enflurane markedly lengthened burst and inter-burst durations. Isoflurane acted in a similar manner, but effects were less pronounced. In contrast with isoflurane and enflurane, halothane shortened burst durations. At concentrations corresponding to 1-1.5 MAC, halothane, isoflurane and enflurane significantly depressed action potential firing by 15-30% (P < 0.05). Enflurane 1.2 mmol litre-1 (2.0 MAC), isoflurane 0.9 mmol litre-1 (2.8 MAC) and halothane 0.9 mmol litre-1 (3.8 MAC) depressed spontaneous spike rates by 50%. The changes in discharge patterns and the concentration-dependent decrease in the firing rates were similar at 23 +/- 1 degrees C and 35 +/- 1 degrees C. In summary, we observed that neither the anaesthetic-induced alterations in spontaneous discharge patterns nor the EC50 values of the concentration-dependent depression of the mean firing rates were in accordance with the Meyer-Overton rule. However, at clinically relevant concentrations, depression of average spike rates did not differ significantly between the anaesthetics and thus followed the rule. Our results suggest that anaesthetic actions, which are in accordance with the rule, are frequently masked by several side effects. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://bja.oxfordjournals.org/content/79/5/617.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1093/bja/79.5.617 antkowiaBAntkowiak haraldHHentschke kunoKKirschfeld article 356 Brain Research 1997 8 766 1-2 56-65 Volatile anaesthetics cause changes in the membrane resting potential of central neurons. This effect probably arises from actions on neuronal ion channels, but may also involve alterations in the ion composition of the extracellular space. Since glial cells play a key role in regulating the extracellular ion composition in the brains of mammals, we analyzed the effects of halothane, isoflurane and enflurane on the membrane conductances and ion channels of cultured cortical astrocytes. Astrocytes were dissociated from the neocortex of 0–2-day old rats and grown in culture for 3–4 weeks. Anaesthetic-induced changes in the membrane potential were recorded in the whole cell current-clamp configuration of the patch-clamp technique. We further studied the effects of halothane and enflurane on single ion channels in excised membrane patches. At concentrations corresponding to 1–2 MAC (1 MAC induces general anaesthesia in 50% of the patients and rats), membrane potentials recorded in the presence of enflurane, isoflurane and halothane did not differ significantly from the control values. At higher concentrations, effects of enflurane and halothane, but not of isoflurane, were statistically significant. Single-channel recordings revealed that halothane and enflurane activated a high conductance anion channel, which possibly mediated the effects observed during whole cell recordings. In less than 10% of the membrane patches, volatile anaesthetics either increased or decreased the mean open time of K+-selective ion channels without altering single-channel conductances. In summary, it seems unlikely that the actions of volatile anaesthetics described here are involved in the state of general anaesthesia. Statistically significant effects occurred at concentrations ten times higher than those required to cause half-maximal depression of action potential firing of neocortical neurons in cultured brain slices. However, it cannot be excluded that the changes observed in the membrane conductance of cortical astrocytes disturb the physiological function of these cells, thereby influencing the membrane resting potential of neurons. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/S0006899397005544 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/S0006-8993(97)00554-4 FFelisberti antkowiaBAntkowiak kunoKKirschfeld article 523 Trends In Neurosciences 1996 10 19 10 415-416 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/0166223696844171 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0166-2236(96)84417-1 kunoKKirschfeld article 542 Vision Research 1996 10 36 20 3329-3337 Horizontal rotational head movements were video-taped from pigeons standing freely in a rotating cylinder. The cylinder carried vertically striped patterns approximating a sinusoidally modulated horizontal intensity distribution. We altered systematically various stimulus parameters: spatial wavelength and contrast of the pattern, angular velocity of the pattern motion and mode of motion onset. We found: (1) both gradual acceleration of the patterned cylinder as well as immediate onset of pattern motion elicit the sequence of smooth following and saccadic resetting movement typical of the rotational “stare” head nystagmus; (2) in experiments with rapid onset of pattern motion, velocity of the smooth following response gradually increases to its steady-state level over a period of about 10 sec; (3) the saccadic head rotations are not stereotyped: larger and shorter saccades follow in an irregular sequence, saccadic velocity and average size varies with stimulus conditions; (4) in the range of 0.9–95 deg/sec, the velocity of the following phase increases in parallel with stimulus speed; (5) in the range of spatial wavelengths of the striped patterns from 6 to 45 deg, at a given drum velocity, patterns of short wavelengths elicit optokinetic head rotations with higher gain (head velocity/drum velocity) than patterns of long wavelengths; (6) response velocity increases with pattern contrast (Michaelson contrast 5, 32 and 75%), following approximately a logarithmic relation; (7) our results on rotational optokinetic head movements support the notion that the neural mechanism underlying motion detection operates like a correlation mechanism. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/0042698996000429 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0042-6989(96)00042-9 WTürke HONalbach kunoKKirschfeld article 524 Proceedings of the Royal Society of London B 1996 4 263 1369 459-468 The latencies of visually guided saccadic eye movements can form bimodal distributions. The 'express saccades' associated with the first mode of the distribution are thought to be generated via an anatomical pathway different from that for the second mode, which comprises regular saccades. The following previously published observations are the basis for a new alternative model of these effects: (i) visual stimuli can cause oscillations to appear in the electroencephalogram; (ii) visual stimuli can cause a negative shift in the electroencephalogram that lasts for several hundreds of milliseconds; and (iii) negativity in the electroencephalogram can be associated with reduced thresholds of cortical neurons to stimuli. In the new model both express and regular saccades are generated by the same anatomical structures. The differences in saccadic latency are produced by an oscillatory reduction of a threshold in the saccade-generating pathway that is transiently produced under certain stimulus paradigms. The model has implications regarding the functional significance of spontaneous and stimulus-induced oscillations in the central nervous system. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://rspb.royalsocietypublishing.org/content/263/1369/459.abstract Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rspb.1996.0069 kunoKKirschfeld feilerRFeiler fwoFWolf-Oberhollenzer article 1308 Journal of Neuroscience 1992 10 12 10 3862-3868 We have generated transgenic flies expressing R7 cell-specific opsins in the major class of photoreceptor cells of the Drosophila retina and characterized their spectral properties using high-resolution microspectrophotometry and sensitivity recordings. We show that the Rh3 and Rh4 opsin genes encode UV-sensitive opsins with similar spectral properties (lambda max = 345 nm and 375 nm), and that Rh3 corresponds to the R7p and R7marg class of visual pigments. We have also generated Rh3 and Rh4 isoform-specific antibodies and present an R7 cell map of the Drosophila retina. In a related set of experiments, we show that it is possible to coexpress two different visual pigments functionally in the same cell and produce photoreceptors that display the summed spectral response of the individual pigments. These findings open up the possibility of tuning an animal's visual behavior by targeted expression of combinations of opsin genes to selective types of photoreceptors. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.jneurosci.org/content/12/10/3862.abstract Biologische Kybernetik Max-Planck-Gesellschaft feilerRFeiler RBjornson kunoKKirschfeld DMismer GMRubin DPSmith MSocolich CSZuker article Krschfeld1990 Naturwissenschaftliche Rundschau 1990 2 43 2 55-61 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld kunoKKirschfeld article 1307 Nature 1988 6 333 6175 737-741 Drosophila mutants transformed with a chimaeric gene that expresses the ocellar visual pigment in the major class of photoreceptor cells of the retina were used to investigate the properties of this minor pigment. The photoreceptor cells in which this opsin was misexpressed showed new spectral characteristics and physiology. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.nature.com/nature/journal/v333/n6175/pdf/333737a0.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/333737a0 feilerRFeiler WAHarris kunoKKirschfeld wehrhahnCWehrhahn CSZuker article 3763 Biological Cybernetics 1987 2 55 5 345-354 The sensitivity of flies and locusts to halothane and N2O was investigated. In this paper we report experiments concerning the allover motor activity in the animal as a whole. In order to determine how the size of neurons comes into play under anesthesia we experimented with different but closely related species of flies differing very clearly in size. For the same reason we chose locusts of different developmental states and consequently different size. It came out that the larger insects are more sensitive to anesthetics than the smaller ones. The results confirm one of Sherrington's (1906) conclusions, which says the axon which conducts spikes cannot be the most sensitive part of the neuron to anesthetic action. He ascribed the highest sensitivity to synapses; this, however, does not match with our results. In agreement with our experimental data is the new hypothesis that long dendrites or axonal endings conducting graded potentials are those parts of the CNS that exhibit the highest sensitivity to anesthetic action. Further confirmation of this hypothesis by more direct approaches has to be provided. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF02281980 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF02281980 kunoKKirschfeld VBaier-Rogowski article 3764 Zeitschrift für Naturforschung C 1986 12 41 12 1137-1138 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld article 3762 Vision Research 1986 11 26 11 1771-1777 Spectral sensitivity of the dorsal compound eye ofSimuliid males (Nematocera) shows a maximum in the u.v. at 340 nm, and a shoulder or second, smaller maximum around 430 nm. The visual pigment—based on retinal and therefore a rhodopsin—has its absorption maximum at 430 nm. The 340 maximum is due to a sensitizing pigment that transfers energy to the visual pigment. The properties of theSimuliid-photoreceptor hence are similar to most of the photoreceptors in higher flies (Musca, Calliphora, Drosophila), that also have a u.v.-absorbing sensitizing pigment. The difference is that inSimuliids the sensitizing pigment is not 3-hydroxyretinol as in the higher flies but a different substance, most likely retinol. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/0042698986901276 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0042-6989(86)90127-6 kunoKKirschfeld KVogt article 3760 Der Augenspiegel 1986 2 32 2 30-49 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld article 3758 Journal of Comparative Physiology A 1985 7 157 4 417-421 A light flash given to the eye ofCalliphora leads to a movement of the legs (light induced leg reflex) which most likely normally initiates flight of the animal. This reflex has a short latency (12 to 30 ms, depending upon light intensity) and is quite reproducible without habituation. The spectral sensitivity of the reflex shows that receptors R1-6 most likely govern the input to the reflex in dark adaptation, a contribution of receptors R7 can be demonstrated with selective chromatic adaptation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00615141 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00615141 kunoKKirschfeld KVogt article 3756 Photchemistry and Photobiology 1984 11 40 5 653-659 The fluorescence of housefly photoreceptors was studied in vivo by using the deep pseudopupil technique. Whereas the rhodopsin R490 of the peripheral retinular cells fluoresces negligibly the metarhodopsin M580 fluoresces distinctly in the red. The newly discovered metarhodopsin M’is produced by intense blue light and can be reconverted into rhodopsin by intense long wavelength light. M’also fluoresces in the red; its excitation spectrum and emission spectrum peak at max= 570 and 660 nm respectively. Intense ultraviolet light irreversibly reduces the visual pigment fluorescence as well as the broad band autofluorescence (kmnx 470 nm) originating from non-visual pigments in the fly's eye. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.1984.tb05355.x/abstract Biologische Kybernetik Max-Planck-Gesellschaft 10.1111/j.1751-1097.1984.tb05355.x DGStavenga NFranceschini kunoKKirschfeld article 3755 Naturwissenschaftliche Rundschau 1984 9 37 9 352-364 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld article 3754 Naturwissenschaften 1984 4 71 4 211-211 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00490436 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00490436 KVogt kunoKKirschfeld article 3751 Journal of Comparative Physiology A 1984 3 154 2 175-187 The prolonged depolarizing afterpotential (PDA) is a phenomenon which is tightly linked to visual pigment conversion. In order to determine whether processes underlying PDA induction and depression can spread in space, the PDA was recorded intracellularly in white-eyedCalliphora R1-6 photoreceptors and used to examine interactions between processes induced by activating statistically different photopigment molecules (Figs. 3–6). It was found that a PDA induced by converting some fraction of rhodopsin (R) molecules forward into the metarhodopsin (M) state can be completely depressed by equal or smaller amounts of pigment conversion, backward from metarhodopsin to rhodopsin even when largely different sets of pigment molecules were shifted in the respective directions, in agreement with previous experiments conducted on the barnacle. The characteristics of the afterpotentials obtained following the cessation of strong blue and green light stimuli which did not cause a net pigment conversion was examined (Figs. 7, 8). It was found that these afterpotentials, obtained when nonet R to M conversion took place, could not be depressed by an opposite net large M to R pigment conversion. Accordingly we propose to restrict the term PDA to an afterpotential which can be depressed by a net M to R pigment conversion. It is concluded: (a) that some processes underlying PDA induction and depression inCalliphora must interact at a distance which extends at least to the nearest neighboring pigment molecule, and (b) that inCalliphora photoreceptors net pigment conversion is required in order to induce and depress a PDA. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00604983 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00604983 BMinke kunoKKirschfeld article 3750 Journal of Comparative Physiology A 1984 3 154 2 153-156 Microspectrophotometry has shown that fly rhabdomeres with C40-carotenoid pigments incorporated into their membrane are more resistant to destruction by short wavelength radiation than others, lacking this pigment (Kirschfeld 1982). We show here that the fine structure of those photoreceptors with the carotenoids is also much better preserved after uv-illumination than in cells lacking this pigment. The intensity of uv-illumination in the experiments was higher than in natural conditions in order to enhance the observable effects, but it is concluded that carotenoid pigments in photoreceptors should also serve a protective function under normal conditions. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00604980 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00604980 HZhu kunoKKirschfeld article 3747 Biophysics of Structure and Mechanism 1983 12 9 4 319-328 The sensitizing pigment hypothesis for the high UV sensitivity in fly photoreceptors (R1–6) is further substantiated by measurements of the polarisation sensitivity in the UV. The quantum yield of the energy transfer from sensitizing pigment to rhodopsin was estimated by electrophysiological measurements of the UV sensitivity and the rhabdomeric absorptance (at 490 nm) in individual receptor cells. The transfer efficiency is ≥ 0.75 in receptors with an absorptance in the rhabdomeres of 0.55–0.95. This result suggests that the sensitizing pigment is bound in some way to the rhodopsin. A ratio of two molecules of sensitizing pigment per one rhodopsin is proposed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00535667 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00535667 KVogt kunoKKirschfeld article 3746 Biophysics of Structure and Mechanism 1983 9 9 3 171-180 Responses to continuous spectral scans in the ultraviolet (uv) have been measured intracellularly from the central retinula cells R7 and R8 in the fly (Musca, female). The spectral sensitivities thus obtained have a resolution limited by the bandwidth of the light supplied by the mono-chromator (0.3–1.5 nm). One class of R7 cells, classified as 7y (Kirschfeld et al. 1978) shows three conspicuous peaks of sensitivity at 337, 355 and 373 nm (Fig. 3a). The underlying R8 cells (8y) also show three peaks but at slightly shorter wavelengths — 334, 350, and 369 nm (Fig. 3c), coinciding with those seen in the peripheral photoreceptors R1–6 (Gemperlein et al. 1980; Kirschfeld et al. 1982). Another class of R7 cells (7p) showed a spectral sensitivity function with a single peak at 330 nm. The underlying R8 cells (8p) also show a single-peaked function with maximum at 460 nm (Fig. 3b and d). The results are interpreted as providing evidence for the hypothesis that uv sensitivity in 7y and 8y cells is conferred by a uv absorbing sensitising pigment similar to that demonstrated in R1-6 cells. The spectra of both 7p and 8p cells can be simply interpreted as deriving directly from the absorption of a rhodopsin with the appropriate λ max. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00537814 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00537814 RHardie kunoKKirschfeld article 1311 Biophysics of Structure and Mechanism 1983 3 10 1-2 81-92 Many lines of evidence suggest that the ultraviolet (uv) sensitivity found in the most common photoreceptor class in the fly is due to a sensitizing pigment which transmits the energy of absorbed light quanta to the visual pigment (Kirschfeld et al. 1977). It is shown that the uv extinction of the rhabdomeres has a vibrational fine structure corresponding to that found in the receptors' spectral sensitivity (Gemperlein et al. 1980). The uv extinction is greatly reduced when flies are reared on a carotenoid-deficient diet, in which case the vibrational fine structure in sensitivity is also lost. Properties (extinction, fluorescence) of several groups of substances that could represent the sensitizing pigment are illustrated. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00535544 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00535544 kunoKKirschfeld feilerRFeiler RHardie KVogt NFranceschini article 3748 Trends in Neurosciences 1983 6 97-101 The analysis of biological systems has in many cases revealed almost unbelievable degrees of adaptation, sophistication and efficiency. In the case of sense organs, the ultimate limits to evolution often seem to be imposed by physical constraints rather than by properties of the biological substrate. For example, chemoreceptors respond to individual molecules, mechanoreceptors are sensitive to displacements in the order of 10−8 cm (i.e. the diameter of a hydrogen atom) at the receptive site, and photoreceptors signal the absorption of individual quanta of light. Consequently, when analysing a highly developed sense organ we expect a priori to find a system that is optimized with respect to its structural and functional parameters. However, our knowledge of the mechanisms of Darwinian evolution tells us that in general further improvement could still be possible. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/0166223683900474 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0166-2236(83)90047-4 kunoKKirschfeld article 3744 Journal of Comparative Physiology A 1982 12 146 4 493-500 The longitudinal chromatic aberration (variation in the position of focus with wavelength) of corneal facet lenses of the houseflyMusca domestica is measured directly. The result is shown to agree with that calculated using the thick-lens formulas, the measured lens parameters and the dispersion of the refractive index of the lenses, measured with an interference microscope. The longitudinal chromatic aberration between the two wavelengths of peak absorption of fly rhabdomeres (360 nm and 495 nm) is about 2.5 μm and comparable to the depth of focus of the lens, assuming the lens to be diffraction limited. Chromatic aberration is therefore expected to have little effect on optical image quality in the fly; in particular the effect on the modulation transfer function at the receptor level and on the angular sensitivity of the rhabdomeres is insignificant. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00609445 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00609445 PMcIntyre kunoKKirschfeld article 3714 Proceedings of the Royal Society of London B 1982 8 216 1202 71-85 The effect of light on animal tissues is ambivalent. Light is necessary for many functions, e.g. for vision and, as in the flagellate halobacterium, to gain energy. But light is potentially dangerous: it is capable of destroying cells or their components by photooxidation, especially in the presence of sensitizing pigments such as haems and cytochromes, which are ubiquitous in aerobic cells. Several different examples are discussed to show how a compromise is achieved in animal tissues that for functional reasons receive high exposure to light. Carotenoid pigments, present in many eyes and photoreceptors, seem especially suited to protect against the deleterious effects of light because they absorb the dangerous short wavelength part of the light spectrum. In plant tissue, carotenoids are also well known to be capable of `quenching' photoexcited states of sensitizing pigments and of oxygen, a function that they might have also in animal tissues. A consequence of the considerations is that whenever animal tissues are exposed to higher than usual light levels and/or oxygen pressures cellular damage might occur. Examples are discussed; strategies to circumvent the deleterious effects by photooxidation follow directly from the arguments. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://rspb.royalsocietypublishing.org/content/216/1202/71.abstract Biologische Kybernetik Max-Planck-Gesellschaft 10.1098/rspb.1982.0061 kunoKKirschfeld article 3743 Journal of Comparative Physiology A 1982 6 146 2 145-152 Photoreceptors of flies contain pigment granules which upon illumination of the receptors migrate towards the rhabdomere and act as a ‘longitudinal pupil’. Data in the literature concerning the effect of the pupil on the spectral sensitivity are contradictory. Therefore spectral sensitivity ofMusca photoreceptors upon light adaptation was reinvestigated. The change in spectral sensitivity of fly photoreceptors upon light adaptation as measured by Hardie (1979) was confirmed. Taking into account waveguide optics this change was explained from absorbance spectra of pupillary granules, measured by microspectrophotometry in squash preparations. Furthermore the pupil absorbance spectrum determined in vivo (Stavenga et al. 1973) was interpreted. The absence of a change in spectral sensitivity upon light adaptation measured by pupillary reflexion (Bernard and Stavenga 1979) is explained by a local-triggering of the pupil. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00610232 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00610232 KVogt kunoKKirschfeld DGStavenga article 3742 Sterne und Weltraum 1981 10 10 10 357-358 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld article 3740 Science 1981 9 213 4513 1264-1267 Most rhabdomeres in the eye of the fly (Musca domestica) are fluorescent. One kind of fluorescent emission emanates from a photoproduct of the visual pigment, other kinds may be ascribed to photostable pigments. These phenomena provide not only a means of spectrally mapping the retina but also a new spectroscopic tool for analyzing the primary visual processes in vivo. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencemag.org/content/213/4513/1264.full.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1126/science.7268434 NFranceschini kunoKKirschfeld BMinke article 3741 Journal of Comparative Physiology A 1981 6 145 2 139-152 In male houseflies (Musca domestica) the frontal dorsal region of the eye contains a unique class of central rhabdomere (R7/8) not found in other eye regions or in female flies (Fig. 1). The rhabdomeres may be recognised in vivo by their red autofluorescence, and are called here 7r and 8r respectively. Difference spectra of 7r rhabdomeres, measured by microspectrophotometry of single rhabdomeres are indistinguishable from those of R1–6 (Fig. 2). Intracellular recordings coupled with dye injections have established that: a) 7r cells are indistinguishable from the peripheral photoreceptors R1–6, at least with respect to spectral, angular and absolute sensitivities, response waveform and noise characteristics (Figs. 4, 5; Table 1); b) 8r cells however are clearly distinguishable by virtue of their spectral sensitivity (Fig. 6), noise characteristics and response waveform (Fig. 5). Axonal profiles from cells stained intracellularly with the dye Lucifer yellow (Fig. 9) show that: a) 7r cells do not project to the medulla but terminate in the upper region of the lamina cartridge layer where they also project out one or more lateral branches; b) 8r cells project long axons through to the medulla. Electron microscopic examinations of cells initially identified by their autofluorescence indicate that 7r cells approximate many features of R1–6 cells, including cell body, rhabdomere and axonal diameters. In these respects 8r cells differ and show the characteristic morphology of other R7 and R8 cells (Fig. 8, Table 2). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00605029 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00605029 RHardie NFranceschini WRibi kunoKKirschfeld article 3737 Nature 1981 5 291 5812 241-244 The recent observation of fluorescence emission from photoreceptor cells in flies1 offers a new opportunity to map the distribution of the various spectral types in a highly organized retinal mosaic. Previous studies had led to the conclusion that in each ommatidium the two central receptor cells are quite distinct from their six neighbours in terms of anatomical projection2,3, visual pigment and physiology4. We show here that in a restricted, well defined region of the male eye only, one of these central cells resembles its six neighbours not only in having the same visual pigment and physiological properties, but also in sending its axon to the same neuropile. A clue to the function of this sexually dimorphic retinal organization is given by the fact that these male-specific cells dominate the frontal-dorsal part of the retina (fovea) which is used by the male to track females in aerobatic chases5,6. We suggest that the male fovea, already known to drive sex-specific higher-order neurones7, has sacrificed colour vision for other more vital kinds of information processing such as improving quantum catch and possibly also contrast transfer or movement detection. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.nature.com/nature/journal/v291/n5812/pdf/291241a0.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/291241a0 NFranceschini RHardie WRibi kunoKKirschfeld article 3738 Journal of Comparative Physiology A 1981 3 143 1 3-15 One photoreceptor type (R7y) in the compound eye of fly (Musca) contains, besides the visual pigment, a photostable pigment (most probably a carotene) with maximal absorption in the blue spectral range. The extinction and dichroism due to this pigment are determined, taking into account waveguide properties, birefringence, anomalous dispersion and possible twisting of the rhabdomeres. The concentration of this pigment, if it is a carotene, is rather high: there are 7–10 molecules per rhodopsin molecule. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00606064 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00606064 PMcIntyre kunoKKirschfeld article 3644 Naturwissenschaften 1980 10 67 10 516-516 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF01047639 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF01047639 kunoKKirschfeld KVogt article 3736 Journal of General Physiology 1980 4 75 4 381-402 The cellular origin and properties of fast electrical potentials arising from activation of Calliphora photopigment were investigated. It was found by intracellular recordings that only the corneal-negative M1 phase of fly M potential arises in the photoreceptors' membrane. This M1 phase has all the accepted characteristics of an early receptor potential (ERP). It has no detectable latency, it survives fixation with glutaraldehyde, it is linear with light intensity below pigment saturation, and it is linear with the amount of metarhodopsin activated by light. The Calliphora ERP was found, however, to be exceptional because activation of rhodopsin, which causes the formation of metarhodopsin in 125 microsecond (25 degrees C), was not manifested in the ERP. Also, the extracellularly recorded ERP was not proportional to the rate of photopigment conversion. The corneal-positive M2 phase of the M potential was found to arise from second-order lamina neurons (L neurons). Intracellular recordings from these cells showed a fast hyperpolarizing potential, which preceded the normal hyperpolarizing transient of these cells. This fast potential appeared only when metarhodopsin was activated by a strong flash. The data indicate that the intracellularly recorded positive ERP, which arises from activation of metarhodoposin, elicits a hyperpolarizing fast potential in the second-order neuron. This potential is most likely the source of the corneal-positive M potential. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://jgp.rupress.org/content/75/4/381.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1085/jgp.75.4.381 BMinke kunoKKirschfeld article 3735 Nature 1980 2 283 5750 859-860 In photoreceptors, a latency of many milliseconds elapses between the absorption of a light quantum and the occurrence of the late receptor potential, even for strong light stimuli. Surprisingly, this is much longer than the time necessary for conductance changes such as occur in membranes of neurones or muscles, mediated by chemical transmitters. There are several possible explanations for the long photoreceptor latency. (1) It may be due to properties of the visual pigment molecules. For instance, the temporal coincidence of the occurrence of metarhodospin II with the receptor signal indicates that the meta I-meta II transition might be the trigger for the electrical response in vertebrate photoreception. (2) It may be explained by properties of transport processes. Such a time consuming process could be the diffusion of an internal 'transmitter substance', which diffuses to a 'pore' in the receptor membrane. (3) A third possibility is the time needed to produce and accumulate chemical substances. The light-induced change of the visual pigment molecule might trigger a chemical reaction chain, in which the product of an earlier step triggers the next one. The experiments described here show that a considerable part of the long latency in photoreception is due to processes that are localised at the level of the visual pigment molecule. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.nature.com/nature/journal/v283/n5750/abs/283859a0.html Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/283859a0 KHamdorf kunoKKirschfeld article 3734 Zeitschrift für Naturforschung C 1980 1 35 1-2 173-174 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en KHamdorf kunoKKirschfeld article 3717 Biophysics of Structure and Mechanism 1979 6 5 2-3 117-128 The photoreceptors in the fly's ommatidia contain a bistable visual pigment, which can be shifted back and forth by means of light of appropriate wavelengths. The situation is complicated, however, by the presence of photostable pigments. One of them (located in rhabdomeres no. 1–6) absorbs in the UV, another one (in rhabdomeres no. 7y) in the blue spectral range. Such pigments act as (dichroic) colour filters that modify the spectral and polarisation sensitivity of the photoreceptors by means of absorption. It could be shown furthermore that such pigments can also act as sensitizing pigments that modify spectral sensitivities due to sensitization. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00535442 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00535442 kunoKKirschfeld article 3733 Journal of General Physiology 1979 5 73 5 517-540 Most of the photoreceptors of the fly compound eye have high sensitivity in the ultraviolet (UV) as well as in the visible spectral range. This UV sensitivity arises from a photostable pigment that acts as a sensitizer for rhodopsin. Because the sensitizing pigment cannot be bleached, the classical determination of the photosensitivity spectrum from measurements of the difference spectrum of the pigment cannot be applied. We therefore used a new method to determine the photosensitivity spectra of rhodopsin and metarhodopsin in the UV spectral range. The method is based on the fact that the invertebrate visual pigment is a bistable one, in which rhodopsin and metarhodopsin are photointerconvertible. The pigment changes were measured by a fast electrical potential, called the M potential, which arises from activation of metarhodopsin. We first established the use of the M potential as a reliable measure of the visual pigment changes in the fly. We then calculated the photosensitivity spectrum of rhodopsin and metarhodopsin by using two kinds of experimentally measured spectra: the relaxation and the photoequilibrium spectra. The relaxation spectrum represents the wavelength dependence of the rate of approach of the pigment molecules to photoequilibrium. This spectrum is the weighted sum of the photosensitivity spectra of rhodopsin and metarhodopsin. The photoequilibrium spectrum measures the fraction of metarhodopsin (or rhodopsin) in photoequilibrium which is reached in the steady state for application of various wavelengths of light. By using this method we found that, although the photosensitivity spectra of rhodopsin and metarhodopsin are very different in the visible, they show strict coincidence in the UV region. This observation indicates that the photostable pigment acts as a sensitizer for both rhodopsin as well as metarhodopsin. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://jgp.rupress.org/content/73/5/517.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1085/jgp.73.5.517 BMinke kunoKKirschfeld article 1310 Zeitschrift für Naturforschung C 1978 11 33 11-12 1009-1010 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld feilerRFeiler BMinke article 1309 Journal of Comparative Physiology 1978 9 125 3 275-284 The population of the centrally located rhabdomeres no. 7 in the ommatidia of flies (Musca, Calliphora, Drosophila) is inhomogeneous: approximately 2/3 of them contain — besides a photoisomerizable rhodopsin — a photostable pigment. Its extinction spectrum has a maximum at 460 nm and two shoulders at 430 and 485 nm respectively. Extinction is maximal for theE-vector perpendicular to the microvilli. Whereas the functional role of the photostable pigment for receptor 7 has still to be worked out, its functional consequence for receptors no. 8, which are located proximal to receptors 7, is obvious: it modifies their spectral sensitivity by selectively absorbing blue light. Due to this “screening”-effect, a shift of the maximal sensitivity of receptors no. 8 is predicted from 490 nm (maximal sensitivity of unscreened receptor 8, Harris et al., 1976) to 520 to 540 nm. This is in agreement with recent electrophysiological data (Hardie, 1977). The results show that spectral sensitivities of receptors no. 8, as determined by means of the ERG of white-eyed mutants or of mutants lacking receptor 7, do not represent the spectral sensitivities of most of these receptors in wild-type flies. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00656606 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00656606 kunoKKirschfeld feilerRFeiler NFranceschini article 3719 Journal of General Physiology 1978 1 71 1 37-45 Microspectrophotometrically derived difference spectra from the barnacles Balanus amphitrite and B. eburneus show that a blue illumination after an orange illumination causes a decrease in absorption in the blue region and an increase in absorption in the green-yellow region, with an isosbestic point around 535 nm. Orange-following-blue illumination causes the reverse changes. The dark time between the adapting and measuring lights has no influence on the data. The results confirm previously reported ERP measurements which indicate that the barnacle visual pigment has two photointerconvertible dark-stable states. If one assumes a Dartnall nomogram shape for the two absorption spectra, a best fit to the observed difference spectra is obtained with nomograms peaking at 492 nm and 532 nm, with a peak absorbance ratio around 1.6:1. These two nomograms fit very well the ERP action spectra of metarhodopsin and rhodopsin, respectively, thus indicating that the ERP is a reliable measure of visual-pigment changes in the barnacle. The existence of a photostable blue pigment is demonstrated in B. eburneus and in some of B. amphitrite receptors, and the possible influence of this photostable pigment on the various action spectra measured in the barnacle is discussed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://jgp.rupress.org/content/71/1/37.full.pdf+html Biologische Kybernetik Max-Planck-Gesellschaft 10.1085/jgp.71.1.37 BMinke kunoKKirschfeld article 3456 Nature 1977 9 269 5627 386-390 Many photoreceptor cells in invertebrates have a dual-peak spectral sensitivity. Evidence is presented that in fly photoreceptors the ultraviolet peak is due to a photostable pigment that absorbs light quanta and transfers the energy to the blue-absorbing visual pigment. http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/KK-36_3456[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.nature.com/nature/journal/v269/n5627/pdf/269386a0.pdf Biologische Kybernetik Max-Planck-Gesellschaft 10.1038/269386a0 kunoKKirschfeld NFranceschini BMinke article 3455 Biophysics of Structure and Mechanism 1977 6 3 2 191-194 In the majority of ommatidia of the fly, the membrane of the central rhabdomere contains — besides the rhodopsin — a photostable pigment. Due to its selective absorption in the blue spectral range, this pigment (possibly a carotene) could modify the spectral sensitivity of the central receptor cells. It furthermore may change the fluidity of the microvillus membrane and hence affect the alignment of rhodopsin molecules. Indirect evidence for a possible role of the photostable pigment as an “antenna”-pigment for rhodopsin is discussed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00535818 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00535818 kunoKKirschfeld NFranceschini article 3454 Zeitschrift für Naturforschung C 1977 5 32 5-6 439-441 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld BLutz article 3449 Biological Cybernetics 1976 12 21 4 181-203 In the compound eye of the fly Musca, tiny pigment granules move within the cytoplasm of receptor cells Nos. 1–6 and cluster along the wall of the rhabdomeres under light adaptation, thus attenuating the light flux to which the visual pigment is exposed (Kirschfeld and Franceschini, 1969). Two recently developed optical methods (the neutralization of the cornea and the deep pseudopupil) combined with antidromic and orthodromic illumination of the eye (Fig. 1) make it possible to analyse the properties of the mechanism at the level of the single cell, in live and intact insects (Drosophila and Musca). The mechanism is shown to be an efficient attenuator in the spectral range (blue-green) where cells Nos. 1–6 have been reported to be maximally sensitive (Figs. 4c and d, 5b and 11b). In spite of the fact that the granules do not penetrate into the rhabdomere, the attenuation spectrum they bring about closely matches the absorption spectrum of the substance of which they are composed (ommochrome pigment, dotted curve in Fig. 11b). The dramatic increase in reflectance of the receptors after light adaptation (Figs. 3, 4b, 5a and 11a) can be explained as a mere by-product of the high absorption index of the ommochrome pigment, especially if one takes into account the phenomenon of anomalous dispersion (Chapter 8). The vivid green or yellow colour of the rhabdomeres would thus have a physical origin comparable to a metallic glint. Contrasting with the lens eye in which the pupillary mechanism is a common attenuator for both receptor types (rods and cones), the compound eye of higher Diptera is equiped with two types of “pupils” adapted respectively to both visual subsystems. A scotopic pupil is present in each of the six cells (Nos. 1–6) whose signals are gathered in a common cartridge of the first optic ganglion. This pupil comes into play at a moderate luminance (0,3 cd/m2 in Drosophila; 3 to 10 cd/m2 in Musca. Figs 13, 14, 15, 16). A photopic pupil is present in the central cell No. 7 whose signal reaches one column of the second optic ganglion. Attenuating the light flux for both central cells 7 and 8, the photopic pupil has its threshold about two decades higher than the scotopic pupil, just at the point where the latter reaches saturation (Fig. 3b, e-State II of Figs. 6b and 15). The photopic pupil itself saturates at a luminance one to two decades higher still (Fig. 3c, f=State III of Figs. 6c and 15). The two-decades-shift in threshold of these pupil-mechanisms supports the view that receptors 1–6 are a scotopic subsystem, receptors 7 and 8 a photopic subsystem of the dipteran eye. The luminance-threshold of the scotopic pupil (as determined with the apparatus described in Fig. 2) appears to be located at least 3.5 decades (Drosophila) or even 5 decades (Musca) higher than the absolute threshold of movement perception (Fig. 16). After a long period (1 hr) of darkness a light step of high intensity can close the scotopic pupil within about 10 sec (time constant τ≃2 sec as in Fig. 9) and the photopic pupil within no less than 30–60 sec. Some mutants of Drosophila possess only a scotopic pupil (w α, Figs. 4 and 5) whereas ommochrome deficient mutants lack both types of pupil (v, cn, see Fig. 7c, d). Comparable reflectance changes, accomplished within about 60 sec of light adaptation, are described for two insects having fused rhabdomes: the bee and the locust (Fig. 17). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00344164 Biologische Kybernetik Max-Planck-Gesellschaft 10.1007/BF00344164 NFranceschini kunoKKirschfeld article 3453 Zeitschrift für Naturforschung C 1976 11 31 11-12 764-765 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld PWenk article 3451 Vision Research 1976 7 16 7 775-778 A quantitative study of optical properties of a photoreceptor requires a knowledge of its characteristic waveguide parameter V. Previously, neither a direct measurement of V nor its accurate determination has been possible. We determine V in almost intact fly photoreceptors by measuring their birefringence. It is shown that the smaller fly photoreceptors have pronounced waveguide effects for wavelengths greater than 400 nm. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/0042698976901887 Biologische Kybernetik Max-Planck-Gesellschaft 10.1016/0042-6989(76)90188-7 kunoKKirschfeld AWSynder article 3447 Zeitschrift für Naturforschung C 1975 1 30 1-2 88-90 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld MLindauer HMartin article 3446 Zeitschrift für Naturforschung C 1974 9 29 9-10 592-596 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld article 3445 Zeitschrift für Naturforschung C 1974 1 29 1 95-97 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld BLutz article 3444 Zeitschrift für Naturforschung C 1973 5 28 5 329-338 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld article 3435 Zeitschrift für Naturforschung B 1972 5 27 5 578-579 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld article 3434 Kybernetik 1971 11 9 5 159-182 In the compound eyes of the fruitflyDrosophila, the dioptric system of each ommatidium is able to form virtual images of the receptor terminals (rhabdomere tips) throughout the whole depth of the eye. It is shown (§ 3) that 3 characteristic superposition phenomena occur for images formed by distinct ommatidia (Figs. 3b and 5). The most remarkable superposition appears at the point where the optical axes of all ommatidia converge (center of curvature of the eye). At this level, highly magnified virtual and erect images of corresponding rhabdomeres are superimposed, giving rise to adeep pseudopupil (Fig. 9). Since in the ommatidia ofDrosophila the rhabdome shows a pattern of 7 distal endings (Fig. 8a), the resultingdeep pseudopupil consists of 7 light spots with a similar pattern (Figs. 8b, 7, 11). Conversely thedeep pseudopupil of compound eyes which have fused rhabdomes consists of a single light spot (Fig. 19). Such pseudopupils can be best observed either with antidromic or with orthodromic illumination of the eye, according to the specific transmission or reflection properties of the rhabdomes. Thedeep pseudopupil of Dipterans is not to be confused with thecorneal pseudopupil (Fig. 13 a) and especially not with thereduced corneal pseudopupil observed with a reduced aperture of the microscope (Fig. 13 b), in spite of the remarkable similarity of these phenomena regarding the asymmetry and the dimension of their pattern (comp. Figs. 7 and 13b). Thereduced corneal pseudopupil consists of 7 facets whereas thedeep pseudopupil consists of 7 virtual images of the receptor endings. From the results of Kirschfeld (1967), the appearance of areduced corneal pseudopupil like Fig. 13 b on the eye ofDrosophila proves that 7 receptors located in 7 neighbouring ommatidia look in the same direction in space (Fig. 14). The existence of such an optical arrangement favors the view that the eye ofDrosophila, like that ofMusca, belongs to the “neural superposition type”. A comparative study between thedeep pseudopupil and thereduced corneal pseudopupil leads to the following geometric relation, which is specific of theDrosophila eye and probably of all compound eyes of the “neural superposition type”: De=Rf′, , whereD is the diameter of a facet,e the distance between the centers of two neighbouring rhabdomere endings,R the radius of curvature of the eye, andf′ the focal length (in air) of a corneal lens. Other types of pseudopupils, commonly appearing as dark spots in compound eyes, are explained on a basis similar to thedeep pseudopupil of Drosophila (§5). In fact, the dioptric system of an ommatidium can give virtual images not only of its distal receptor endings but of the whole intensity distribution (i.e. the whole “luminous structure”) which is present in its internal focal plane. If this structure is simple, thedeep pseudopupil, resulting from superpositions of virtual images, is likewise simple (Figs. 16 and 17). If the “luminous structure” is complex, as for example in the eye of the butterflyVanessa (Fig. 18a schematized in Fig. 18c), then thedeep pseudopupil shows the same complexity (Fig. 18 b and d). In compound eyes which lack screening pigment between their crystalline cones, one can seesecondary pupils of the 1st and 2nd order as described by Exner. Again they may be explained by superpositions of virtual images in the depth of the eye, according to Fig. 20. Moreover, thedeep pseudopupil of the “optical superposition eye” may be due to the fact that the more distal converging system of an ommatidium forms virtual images not of the rhabdome endings themselves but of real images of these endings (Fig. 21). Although the phenomenon of thedeep pseudopupil is not perceived by the animal, it is of interest for the experimenter who can use it: 1) to study the light receptors easily in the eye of live and intact animals, 2) to measure the physiological divergence angle between adjoining ommatidia, 3) to study the movement of the visual axis and the retinomotor adaptation of the receptors, and 4) to stimulate simultaneously manycorresponding receptors belonging to different ommatidia. The advantages of thisin vivo technique are discussed in § 6.3. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF02215177 Biologische Kybernetik Max-Planck-Gesellschaft other 10.1007/BF02215177 NFranceschini kunoKKirschfeld article 3432 Naturwissenschaften 1971 4 58 4 201-209 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00591846 Biologische Kybernetik Max-Planck-Gesellschaft de 10.1007/BF00591846 kunoKKirschfeld article 3433 Kybernetik 1971 1 8 1 1-13 Thanks to a technique of optical neutralisation associated with a transilluinination of the eye, it is possible to study the photoreceptor endings (rhabdomere tips) in the compound eye of live and intact Drosophilae. The success of the neutralisation process directly confirms the idea that the convergence of the dioptric system in each ommatidium is essentially due to the refraction at the corneal outer surface. The remarkable regularity of the asymmetrical receptor pattern throughout the eye (fig. 7) is of functional importance. The divergence angle between the optical axis of neighbouring receptors, and their farfield radiation pattern are shown to depend respectively on the spacing and the diameter of the rhabdomere distal endings (fig. 8). The tip of the centrally located rhabdomere number 7 (fig. 5) is found to have a smaller optical diameter than its six neighbours and the extinction spectrum of this rhabdomere is different from those of the other ones. Modal patterns are observed at the distal tip of the rhabdomeres (fig. 9), confirming the waveguide properties of these components. The eye of Drosophila is morphologically composed of two equal parts, dorsal and ventral, in which the rhabdomere patterns are symmetrical (fig. 7). Sporadic irregularities are found in the border between these two parts (fig. 10). Actually the main importance of this neutralisation technique lies in its possible applications. The simultaneous visualization of a lot of receptors, in transmitted light, allows a precise stimulation, in incident light, of single and known cells in the eye of live insects. This method combined with other in vivo techniques such as those using the phenomenons of “corneal pseudopupil” (Kirschfeld and Franceschini, 1968) and “deep pseudopupil” (Franceschini and Kirschfeld, 1971a) may simplify further studies regarding the nervous integration of visual stimuli in the facet eye. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00270828 Biologische Kybernetik Max-Planck-Gesellschaft other 10.1007/BF00270828 NFranceschini kunoKKirschfeld article 3431 Neurosciences Research Program Bulletin 1970 12 8 5 474-475 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft en kunoKKirschfeld article 1721 Zeitschrift für Naturforschung B 1970 2 25 2 228 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld wreichardtWReichardt article 3426 Kybernetik 1969 5 6 1 13-22 In the ommatidia of Musca, the light flux transmitted by each one of the rhabdomeres of sense cells no. 1 to 6 decreases as a function of time if light falls onto these rhabdomeres. With a similar time course the light flux reflected from these rhabdomeres increases. These changes take place within a few seconds following illumination. The results have been established in the intact animal using changes in the appearance of the pseudopupil as indicator and also in surviving preparations of the eye with direct inspection of the rhabdomeres. The changes are interpreted as a consequence of interactions between pigment granules in the sense cells and electromagnetic fields induced outside the rhabdomeres by light travelling on the inside: In the dark adapted situation the granules are quite distant from the rhabdomeres, the interaction is negligible. During light adaptation the granules move close to the rhabdomeres, and as a consequence, total reflection of the light in the rhabdomere is frustrated. The relatively rapid changes in the optical characteristics of the rhabdomeres are explained by the fact that the distance, the granules have to move in order to switch from one condition to the other is in principle on the order of the wavelength of light. The results indicate, that the changes in the position of the granules are induced by the excitation of the respective sense cells themselves, for instance by the degree of their depolarisation. No interaction between the sense cells of one ommatidium nor between those of different ommatidia could be found. The function of the movement of the pigment granules is interpreted as a means to protect the sense cells no. 1 to 6 against strong illumination. — Movement of pigment granules is not induced in sense cells no. 7 and 8 with light intensities which give maximal response in sense cells no. 1 to 6. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00288624 Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen de 10.1007/BF00288624 kunoKKirschfeld NFranceschini article 3400 Kybernetik 1968 8 5 2 47-52 Optical characteristics of the dioptric system in the ommatidia of Musca have been analysed by use of “antidromic illumination” of the eye. The results indicate that the distal endings of the rhabdomers terminate near the focal plane of the dioptrics and that the quality of the lens is high enough to resolve some details of their shape. — Using optical methods it has been possible to confirm directly that the optical axes of 7 individual rhabdomers from 7 different ommatidia all converge to a common point in the distant surroundings. This is a characteristic for compound eyes of the “neural superposition” type. — The results are discussed on the basis of the hypothesis that the Musca eye is composed of two functionally different subsystems: One system (D) with high absolute sensitivity and low spatial resolution consisting of the sense cells no. 1 to 6, and a second system (H) with high spatial resolution and low absolute sensitivity composed of cells no. 7 and 8. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007%2FBF00272694 Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen de 10.1007/BF00272694 kunoKKirschfeld NFranceschini article 3401 Mitteilungen der Max-Planck-Gesellschaft 1968 1968 3 185-206 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Department Braitenberg Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen de braitenbVBraitenberg kunoKKirschfeld article 3396 Experimental Brain Research 1967 3 3 3 248-270 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/KK-8_3396[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt http://www.springerlink.com/content/9d2d88a70de5c7c7/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen de 10.1007/BF00235588 kunoKKirschfeld article 3394 Umschau in Wissenschaft und Technik 1966 8 66 15 500-501 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kyberntik, Tübingen de kunoKKirschfeld article 3393 Kybernetik 1965 10 2 6 249-257 The sensitivity distribution of visual elements in the front region of the compound eye of Musca is investigated by means of intracellular micropipette recording. This distribution approximates a Gauss-function of 7.7 degree half-value in the horizontal plane. Using a “bleaching effect” of the Musca compound eye as an indicator, the angular distances between the optical axes of adjacent ommatidia are measured and found to vary between 2.3 and 3.9 degrees. Thus the visual fields of adjacent ommatidia strongly overlap. Based on these findings a calculation reveals that less than 12% of the mean efficient light flux is received from the anatomically determined visual field of the ommatidium. Similar percentages for Calliphora (less than 20%) and Limulus (less than 19%) result from evaluation of data collected by other investigators. — Light entering the visual element from different directions (more than 5° apart) is demonstrated to be 1.2 to 1.4 times more effective than light received from the same direction. — Consequences of the overlap of visual fields of adjacent ommatidia for perception of motions and patterns by the compound eye are discussed. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt http://link.springer.com/content/pdf/10.1007%2FBF00274088 Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen de 10.1007/BF00274088 kunoKKirschfeld article 1738 Kybernetik 1964 6 2 2 43-61 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt http://springerlink.metapress.com/content/hm42688235u03w11/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft de 10.1007/BF00288558 kunoKKirschfeld wreichardtWReichardt article 3391 Zeitschrift für vergleichende Physiologie 1961 4 44 4 371-413 Das Elektroretinogramm der untersuchten Rüsselkäfer auf einen Hellreiz hat die von Limulus, Dixippus und anderen Arthropoden bekannte Form eines langsamen, monophasischen ERGs: Nach einer Latenzzeit von etwa 20 msec erfolgt innerhalb von 10–200 msec ein Potentialanstieg auf gleichbleibende Höhe (maximal 10–20 mV). Bei starken Reizen erfolgt ein „Überschwingen“ vor Erreichen des konstanten Wertes (Abb. 4a und b). Der Vorgang des Abklingens nach Reizschluß dauert 100 msec bis 15 sec. Maß für die Geschwindigkeit der An- und Abklingvorgänge sind die Anstiegs- und die Abfallshalbwertszeit: Je größer das Verhältnis der Reizgröße ΔI zur Adaptationslicht-Intensität I a, und damit, je größer die Amplitude der ERGs ist, desto kleiner ist die Anstiegs-, desto größer die Abfallshalbwertszeit (Abb. 5, 6 und 7). Auch auf Dunkelreize erfolgt nach einer Latenzzeit von etwa 20 msec ein Potentialabfall im Verlauf von 100 msec bis 15 sec. Auch dessen Halbwertszeit ist um so kleiner, je kleiner das Verhältnis —Δ I/I a ist. Die Kurvenform ändert sich dabei mit dem Kleinerwerden des Dunkelreizes erheblich (Abb. 11). Der Potentialanstieg nach Ende des Dunkelreizes erfolgt in 10–200 msec entsprechend dem Anstieg auf Hellreize (s. Punkt 1 der Zusammenfassung). Bei Reizung mit rechteckförmigen Lichtreizen hängt die Amplitude der ERGs für Reizzeiten von weniger als 200 msec im Bereich Δ I/I a zwischen -1 und +1 linear von der Reizgröße Δ I ab (Abb. 15b). Der Zusammenhang wird um so mehr logarithmisch, je länger die Reizzeit und je größer das Verhältnis Δ I/I a wird (Abb. 15a, 35). Dies liegt nicht nur daran, daß ein kleiner Ausschnitt aus einem nichtlinearen Zusammenhang durch eine Gerade angenähert werden kann, sondern auch an der besonderen Kinetik, mit der sich das Potential auf Dunkelreize einstellt (vgl. Punkt 2 der Zusammenfassung sowie Abb. 11, 15 und 16). Auf Reizung mit Sinuslicht treten zwei verschiedene, durch Übergänge miteinander verbundene ERG-Formen auf: sinusförmige und solche von der Form U ∼ log sin I. Das ERG nähert sich um so mehr der Sinusform, je höher die Reizlicht-Frequenz und je kleiner das Verhältnis der Reizgröße Δ I zur Minimal-Intensität I 1 wird (Abb. 26, 27). —Dies ergibt sich zwangsläufig aus Punkt 3 der Zusammenfassung, wenn man die Zusammenhänge zwischen Amplitude und Reizgröße, wie sie sich bei Reizung mit rechteckförmigen Reizen verschiedener Dauer ergeben, als Kennlinien betrachtet (Abb. 36). Die Dunkeladaptation ist bei den gewählten Versuchsbedingungen in 10–1000 sec abgeschlossen (Abb. 19, 21). Die Reaktion auf Testimpulse erreicht um so später einen bestimmten Prozentsatz (80%) der ERG-Amplitude des vollständig dunkeladaptierten Auges, je länger die Dauer und je größer die Intensität der vorausgegangenen Helladaptation gewesen ist (Abb. 19–22). Erfolgt Dunkeladaptation an eine bestimmte niedrige Helligkeit I a 2 anstatt an völlige Dunkelheit, so wird die jeweilige 80%-Amplitude um so schneller erreicht, je größer I a 2 ist (Abb. 23). Die Helladaptation ist immer schon nach wenigen Sekunden abgeschlossen (Abb. 24). Der Verlauf der Adaptation wird somit nicht durch eine Zeitkonstante bestimmt, wie z.B. bei der Lichtwachstumsreaktion von Phycomyces; die Adaptation gehorcht komplizierteren Gesetzmäßigkeiten. Die Amplitude der ERGs bei Reizung mit rechteck- und sinusförmigen Lichtreizen bleibt annähernd konstant, wenn bei Variation von Δ I und I dafür gesorgt wird, daß Δ I/I konstant bleibt (Abb. 29, 34). Dieser Zusammenhang ergibt sich beim ERG der Rüsselkäfer aus dem logarithmischen Zusammenhang zwischen der Lichtintensität und dem von den Sinneselementen erzeugten Potential (s. Punkt 3 der Zusammenfassung). Der Vergleich mit Ergebnissen verhaltensphysiologischer optomotorischer Experimente ergibt, daß der Reizzeitbereich (s. Zusammenfassung Punkt 3), innerhalb dessen Reizlichter linear in Erregung übersetzt werden, bei Verhaltens- und elektrophysiologischen Experimenten der gleiche ist. Es zeigt sich, daß in beiden Arten von Experimenten bei gleichen Reizzeiten die lineare in eine nichtlineare Übersetzung übergeht. Die Verformung des linearen Reiz-Reaktions-Zusammenhanges erfolgt in derselben Richtung: Das physiologische mittlere Grau wird zu dunkleren Grauwerten verschoben (Kap. G, 1). Die an den Augen elektrophysiologisch gemessenen Übertragungseigenschaften des ERGs entsprechen den Eigenschaften einer bestimmten Instanz (des H-Filters) der Funktionsstruktur (Abb. 37, 38), die von Hassenstein, Reichardt und Varjú aus der Analyse des optomotorischen Verhaltens des Rüsselkäfers Chlorophanus erschlossen worden war. Unter der Voraussetzung, daß das ERG diese Übertragungs-Instanz der Funktionsstruktur repräsentiert, kann eine offengebliebene Frage beantwortet werden: Die H-Filter liegen vor den D-Filtern. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt http://link.springer.com/content/pdf/10.1007%2FBF00388036 Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kyberntik, Tübingen de 10.1007/BF00388036 kunoKKirschfeld article 3390 Zeitschrift für Naturforschung B 1959 3 14 3 212-213 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft MPI für biol. Kybernetik, Tübingen de kunoKKirschfeld inproceedings 1313 Proc. XVIII Intern. Congress of Entomology, Vancouver, Canada, July 3 to 9, IIIG3 1995 111 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Anderson, R.S. , C.H.C. Lyal Entomological Society of Washington

Washington, DC, USA

Biology and phylogeny of Curculionoidea Biologische Kybernetik Max-Planck-Gesellschaft Vancouver, Canada XVIII International Congress of Entomology 1988 MGewecke kunoKKirschfeld feilerRFeiler inproceedings 3761 1986 31-49 Besides the “classical” chromophores retinal (visual pigment: rhodopsin) and 3-dehydroretinal (visual pigment: porphyropsin), recently a new chromophore has been found in several insect groups: 3-hydroxyretinal (visual pigment: xanthopsin). Evolutionary aspects are considered — the first interaction of light with the photoreceptor must not necessarily take place at the Schiff base-linked chromophore. In many photoreceptors, e.g., of many fly species, light can be absorbed by a sensitizing pigment which then transfers energy (Förster mechanism) to the Schiff base-linked chromophore. This chromophore is then isomerized and leads to excitation of the receptor. The sensitizing pigment in higher flies is identified as 3-hydroxyretinol, and in one more primitive fly species (Simuliid) most likely as retinol. Functional consequences of sensitization are illustrated. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/chapter/10.1007/978-3-642-70444-4_3 Stieve, H. , M.L. Applebury Springer

Berlin, Germany

The Molecular Mechanism of Photoreception Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany Dahlem Workshop on the Molecular Mechanism of Photoreception 1984 3-540-15363-2 10.1007/978-3-642-70444-4_3 kunoKKirschfeld inproceedings 3759 1985 6 101-117 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Barth, F.G. Fischer

Stuttgart, Germany

Verhandlungen der Deutschen Zoologischen Gesellschaft Biologische Kybernetik Max-Planck-Gesellschaft Wien, Austria 78. Jahresversammlung der Deutschen Zoologischen Gesellschaft 3-437-30501-8 kunoKKirschfeld inproceedings 3757 1985 375-386 The primary process induced by absorption of a quantum of light in a visual pigment molecule is the isomerization of the chromophore retinaldehyde from the all-cis to the all-trans form (Wald 1968). I will show here that besides this direct interaction between light and visual pigment another process can take place: the light quantum can be absorbed by an accessory pigment which then transfers energy to the normal, Schiffbase linked chromophore of the visual pigment, which then will be isomerized. The photostable, accessory pigment therefore is acting as a sensitizing pigment. We have investigated the process of sensitization in some detail in the most common type of receptor of the fly (type Rl-6); we show, however, that sensitization of visual pigments is realized in other types of receptors of the fly and in many other insect species as well. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/content/pdf/10.1007/978-3-642-87599-1_24 Gilles, R. , J. Balthazart Springer

Berlin, Germany

Neurobiology: Current Comparative Approaches Biologische Kybernetik Max-Planck-Gesellschaft Liège, Belgium 1st International Congress of Comparative Physiology and Biochemistry 1984 978-3-642-87601-1 10.1007/978-3-642-87599-1_24 kunoKKirschfeld inproceedings 3752 1984 29-39 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Borsellino, A. , L. Cervetto Plenum Press

New York, NY, USA

Photoreceptors Biologische Kybernetik Max-Planck-Gesellschaft Erice, Italy NATO Advanced Study Institute on Photoreceptors 1981 0-306-41629-8 kunoKKirschfeld inproceedings 3442 Symposial Papers of the International Biophysics Congress 4 1974 289-296 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Frank, G.M., L.P. Kayushin Academy of Sciences of the USSR

Puščino, Soviet Union

International Biophysics Congress 4 Biologische Kybernetik Max-Planck-Gesellschaft International Union for Pure and Applied Biophysics Moskva, USSR 4th International Biophysics Congress of the International Union for Pure and Applied Biophysics (IUPAB 1972) en kunoKKirschfeld inproceedings 3441 1973 229-257 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Lindauer, M. Fischer

Stuttgart, Germany

Fortschritte der Zoologie ; 21,2/3 Orientierung der Tiere im Raum: Sinnes- und neurophysiologische Grundlagen Biologische Kybernetik Max-Planck-Gesellschaft Mainz, Germany 1. Internationales Symposium der Akademie der Wissenschaften und der Literatur zu Mainz 1972 de kunoKKirschfeld inproceedings 3427 1969 116-136 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt Reichhardt, W. Academic Press

New York, NY, USA

Rendiconti della Scuola Internazionale di Fisica Enrico Fermi ; 43 Processing of optical data by organisms and machines Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen Varenna, Italy International School of Physics "Enrico Fermi": Course XLIII, 1968 en kunoKKirschfeld inproceedings 3428 1969 144-166 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt Reichardt, W. Academic Press

New York, NY, USA

Rendiconti della Scuola Internazionale di Fisica Enrico Fermi ; 43 Processing of optical data by organisms and machines Biologische Kybernetik Max-Planck-Gesellschaft Varenna, Italy International School of Physics "Enrico Fermi": Course XLIII, 1968 en kunoKKirschfeld inproceedings 3402 Proceedings of the 23rd Symposium of the Zoological Society of London 1968 165-166 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Carthy , J.D. , G.E. Newell Academic Press

London, UK

Symposia of the Zoological Society of London ; 23 Invertebrate Receptors Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen London, UK 23rd Symposium of the Zoological Society of London 1967 en kunoKKirschfeld inproceedings 3395 Proceedings of the International Symposium on "The Functional Organization of the Compound Eye" 1966 291-307 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt Bernhard, C. G. Pergamon Press

Oxford, UK

The functional organization of the compound eye Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kyberntik, Tübingen Stockholm, Sweden International Symposium on the Functional Organization of the Compound Eye 1965 en kunoKKirschfeld inbook 5648 2008 243-268 http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/MSBaumannGesamt.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://books.google.de/books?id=6W1K-nim70oC&pg=PP1&lpg=PP1&dq=Was+bedeutet+Leben?+:+Beitr%C3%A4ge+aus+den+Geisteswissenschaften&source=bl&ots=zIoHLhYlUH&sig=uJvrQWI3lrFBbL6pJH3jB-vPN3s&hl=de&sa=X&ei=s5ldUYmcFYHI4ASH04C4BQ&ved=0CEwQ6AEwAw Baumann, U. Lembeck

Frankfurt a. M., Germany

Was bedeutet Leben?: Beiträge aus den Geisteswissenschaften Biologische Kybernetik Max-Planck-Gesellschaft de 978-3-87476-565-7 kunoKKirschfeld inbook 1177 2001 385-405 Licht hat sowohl Quanten- als auch Wellencharakter (Dualismus von Welle und Korpuskel). Je nach Versuchsanordnung wird die eine oder die andere Eigenschaft wirksam: Wann immer Licht absorbiert wird, z.B. im Sehfarbstoff-Molektil, läßt sich dies als Quantenprozeß beschreiben. Wird mittels Licht dagegen ein Objekt z. B. durch ein Linsensystem abgebildet, so ermöglicht die Vorstellung von Licht als einer transversalen Welle die quantitative Behandlung der Phänomene. Aus dem riesigen Wellenlängenbereich elektromagnetischer Strahlung, der von der Sonne die Erde erreicht, wird von Mensch und Tier nur ein kleiner Ausschnitt — Wellenlängen von etwa 300 nm (ultraviolett) bis 750 nm (rot) — zum Sehen ausgenutzt. Fär die Einschränkung auf diesen Wellenlängenbereich gibt es verschiedene plausible Gründe. För die Begrenzung am kurzwelligen Ende des Spektrums gelten im wesentlichen drei: Die Quantenzahl der Strahlung im ultraviolett en Spektralbereich, die an der Erdoberfläche ankommt, ist relativ gering (Abb. 17-1a). Die Sonne als Strahler von etwa 6000° K strahlt relativ wenig UV-Licht ab. Zusätzlich wird das Licht in der Atmosphäre vor all em durch die Absorptionsbanden des Ozons stark geschwächt und bis zu einer Wellenlänge von etwa 300 nm fast völlig unterdrückt. Die Streuung des Lichtes an Luftmolekülen sorgt außerdem für beträchtliche Veränderungen im Spektrum des auf der Erdoberfläche ankommenden Lichtes. Augenmedien streuen Licht. Die Streuung ist dabei urn so stärker, je kürzer die einfallende Wellenlänge ist. Bei großen Augen mit langen optischen Wegen wie dem des Menschen wirkt sich die Lichtstreuung besonders stark aus (Abb. 17-1b). UV-Sehen ist deshalb Bur bci Tieren mit relativ kleinen Augen zu erwarten und bisher auch nur da gefunden worden. Kurze UV-Strahlung führt zu Fluoreszenz der Augenmedien (Linsen, Glaskörper) und wird damit zum Sehen unbrauchbar, weil dieses Fluoreszenzlicht keine Information über die Helligkeitsverteilung in der Umwelt enthält, sondern im Gegenteil den Bildkontrast auf der Retina reduziert und damit die Qualität des Bildes beeinträchtigt. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/chapter/10.1007%2F978-3-642-56497-0_17 Dudel, J. , R. Menzel, R.F. Schmidt Springer

Berlin, Germany

2. Neurowissenschaft: vom Molekül zur Kognition Biologische Kybernetik Max-Planck-Gesellschaft 978-3-540-41335-6 10.1007/978-3-642-56497-0_17 kunoKKirschfeld inbook 439 1997 67-93 Course control and tracking are based on visual detection of the position and movement of objects. A disadvantage of biological movement detectors is that they cannot provide a signal proportional to the speed at which the image of an object moves over the retina. Other image parameters, such as brightness, contrast, and texture, strongly affect the magnitude of the detectors’ output signals. To function well, the optomotor control circuit must solve these problems. One possible solution, realized in Diptera, is the principle of “gain control by feedback oscillations” described in this chapter. The optomotor system serves for course control by stabilizing the image of the visual panorama on the eye, and for tracking a moving object by stabilizing the object’s image on the eye. When an object moves in front of a structured background, it is impossible for the images of both object and background to be stabilized simultaneously. Arthropods and vertebrates usually employ the same strategy to cope with this problem: saccadic tracking. In Diptera, the neural substrate for saccadic tracking is partially understood. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/chapter/10.1007/978-3-0348-8878-3_3 Lehrer, M. Birkhäuser

Basel, Switzerland

EXS ; 84 Orientation and communication in arthropods Biologische Kybernetik Max-Planck-Gesellschaft 3-7643-5693-6 10.1007/978-3-0348-8878-3_3 kunoKKirschfeld inbook 606 1996 383-403 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Dudel, J. , W. Backhaus Springer

Berlin, Germany

Neurowissenschaft: vom Molekül zur Kognition Biologische Kybernetik Max-Planck-Gesellschaft 3-540-61328-5 kunoKKirschfeld inbook 3739 1981 142-162 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Laverack, M.S. Blackie

Glasgow, UK

Sense Organs Biologische Kybernetik Max-Planck-Gesellschaft 0-216-91094-3 kunoKKirschfeld inbook 3732 1979 297-310 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Schmitt, F.O. , F.G. Worden MIT Press

Cambridge, MA, USA

The Neurosciences: Forth Study Program Biologische Kybernetik Max-Planck-Gesellschaft 0-262-19162-8 kunoKKirschfeld inbook 3452 1976 354-370 Two distinctly different types of eyes have been highly developed in evolution: lens eyes (= camera eyes) in vertebrates, some molluscs and arachnids and compound eyes in arthropods. Based on his comparative studies of the optical properties of compound and lens eyes, Exner (1891) concluded that both types of eyes are optimally adapted for different functions: lens eyes with their high angular resolution seem to more useful for pattern recognition, whereas the compound eyes, with their poor resolution, are thought to be specialized for movement perception. This view is still generally accepted (see the textbooks of Scheer, 1969, Kaestner, 1972). Furthermore, the small facet diameters of the ommatidia in compound eyes seem to cause a poor absolute sensitivity (Exner, 1891; Barlow, 1952; Kirschfeld, 1966; Prosser and Brown, 1969; Snyder et al., 1973). Some insects are said, however, to have higher temporal resolution than humans (Autrum, 1948). http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/KK-32_3452[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/chapter/10.1007/978-3-642-66432-8_19 Zettler, F. , R. Weiler Springer

Berlin, Germany

Neural Principles in Vision Biologische Kybernetik Max-Planck-Gesellschaft 3-540-07839-8 10.1007/978-3-642-66432-8_19 kunoKKirschfeld inbook 3448 1975 56-77 There are eight photoreceptors in each ommatidium of the compound eye of the fly, Musca Six of them (numbered 1 to 6) are similar with respect to the size of their rhabdomeres. They are different from the two others, the receptors no. 7 and 8, which are thinner and shorter. The difference between the two types of receptors is not limited to their size. Each type is the input to one of two different subsystems of the visual system of the fly (KIRSCHFELD and FRANCESCHINI, 1968; review KIRSCHFELD, 1973). http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://link.springer.com/chapter/10.1007/978-3-642-80934-7_4 Synder, A.W. , R. Menzel Springer

Berlin, Germany

Photoreceptor optics Biologische Kybernetik Max-Planck-Gesellschaft en 3-540-07216-0 10.1007/978-3-642-80934-7_4 kunoKKirschfeld AWSynder inbook 3436 1972 61-74 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Wehner, R. Springer

Berlin, Germany

Information Processing in the Visual Systems of Arthropods Biologische Kybernetik Max-Planck-Gesellschaft en 3-540-06020-0 kunoKKirschfeld inbook 3430 1970 105-113 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Department Braitenberg Frank, H. Umschau Verlag

Frankfurt a. M., Germany

7. Kybernetik: Brücke zwischen den Wissenschaften Biologische Kybernetik Max-Planck-Gesellschaft de braitenbVBraitenberg kunoKKirschfeld poster 4836 2006 3 9 96 The general consensus is that the brain is something different from the mind: it is made of physical substance, and is subject to the laws of physics. The mind, however, cannot be described by physical methods. It is considered to be related to experiences such as perceptions or consciousness. The question of the connection between mind and brain, or that of body and soul, is probably the most profound problem at the interface between the “sciences” and the “arts”. That signals can be emitted by the brain and then enter our consciousness—and thus that the brain influences the mind—is hardly in dispute. Indeed, psychophysics is even capable of specifying a quantitative relationship between a physical stimulus and the sensation it elicits. Opinion is more divided regarding the question of whether the mind can also influence the brain. German criminal law presupposes that it does [1], and the sociologist J¨urgen Habermas shares this view [2].The concept that the brain determines the mind is consistent with the laws of physics. But this does not apply to the opposite concept, that the mind can affect the brain: an ability of the “mind” to modify the activity of nerve cells would contradict the principle of causality. Benjamin Libet [3], however, takes the latter concept as a starting point in one of his much-discussed experiments on the question of conscious free will. He measured how long it takes for us to make a voluntary movement after we become aware of the fact that we want to make it, and found that the delay was about 200 ms. Surprisingly, however, brain potentials that indicated the initiation of the movement were measurable more than 500 ms before the movement occurred. The conclusion: the “will” cannot trigger the movement, because it is evidenced 300 ms too late. If the opposite result had been obtained, so that the will to act was apparent prior to the brain activity, the conclusion would have been that this result is indeed consistent with the notion that the “will” initiated the movement. Furthermore, Libet concludes that “conscious control over the actual motor performance of the acts remains possible”. Another interpretation of his results, which however can be reconciled with the laws of physics, is as follows. Brain activity initiates both the activation of the muscles that produce the movement, and also the perception that one is “willing” to make the movement. Which of these processes first becomes apparent has no implications regarding the causal relationships. As long as one takes it as given that laws of physics apply to the brain, the possibility that the “will” initiates movements is ruled out. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.twk.tuebingen.mpg.de/twk06/abstract.php?_load_id=kirschfeld01 Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 9th Tübingen Perception Conference (TWK 2006) en kunoKKirschfeld poster 3323 Investigative Ophthalmology & Visual Science 2005 5 46 Supplement B857 Purpose: We developed a model according to which alpha waves are generated by a feedback loop. The gain in the loop is so high that it acts as a band–pass filter with maximal frequency in the range 8 – 12 Hz (alpha band). According to this model light adaptation should lower the gain in the loop, with the consequence that evoked potentials and alpha–wave amplitudes decrease. This has been verified experimentally (K. Kirschfeld, Program No. 985.18. 2004 Abstract Viewer Washington, DC: Society for Neuroscience). In contrast to light adaptation, attention is expected to increase the gain in the same loop, together with the amplitude of alpha waves. The purpose of this study is to test this prediction. Methods: Observers were asked to press one of two buttons depending upon whether a repetitively presented white square has been presented above or below a fixation point. Alpha waves were recorded at the occiput (electrode position Oz). Results: Alpha wave amplitudes are high in the time window in which a stimulus is to be expected, and low outside this time window. The amplitude is the higher, the higher the probability of the target’s occurrence. The change between low and high alpha amplitudes can be rather fast, less than a second in each direction. Conclusions: The effect is so robust and strong that it is likely that the mechanism which generates alpha waves is functionally relevant to the adjustment of sensitivity (gain) for neural processing, in which process light adaptation and attention have opposite effects. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://abstracts.iovs.org/cgi/content/abstract/46/5/5654 Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Institut für biologsche Kybernetik, Tübingen Fort Lauderdale, FL, USA Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO 2005) kunoKKirschfeld poster 3231 2004 10 34 985.18 When the eyes are closed the visual cortex generates high-amplitude oscillations in the alpha frequency range (8 to 13 Hz) which can be recorded on an electroencephalogram (EEG). This low input state is thought to reflect cortical idling. Here I propose that in fact the opposite is correct: large oscillation amplitudes reflect a state of alertness, that is high sensitivity in the visual system, preparing it to respond to weak stimuli. Opening the eyes reduces the amplitudes of the alpha oscillations (Berger effect). This is at least partly due to light adaptation indicating a loss of sensitivity. This relatively slow (compared to 10 Hz alpha frequency) light adaptation with a time constant of some 300 ms is the nonlinear component in the alpha EEG. Brain oscillations are commonly thought to be generated by (nonlinear) oscillators. I propose that - as occasionally suggested - alpha waves basically are the outcome of a linear process such as band-pass filtering. I demonstrate that the superposition law holds (which defines linearity of a system): evoked potentials are just superimposed on on-going alpha waves. The phase of the latter is not affected. The results are in agreement with the view that alpha waves and the 10 Hz components of visually evoked potentials are generated by the same linear mechanism. The linearity of the alpha waves generating mechanism implies that visual input cannot modify the phase of on- going alpha waves. If the same is also true for gamma oscillations, theories on brain oscillations which imply phase resetting by visual input (temporal correlation hypothesis) are questioned. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sfn.org/Annual-Meeting/Past-and-Future-Annual-Meetings/Abstract-Archive Biologische Kybernetik Max-Planck-Gesellschaft Max Planck Insitut f. biologische Cybernetics, Tübingen San Diego, CA, USA 34th Annual Meeting of the Society for Neuroscience (Neuroscience 2004) kunoKKirschfeld poster 3230 2004 2 7 104 The function of brain oscillations is seen in the context of various sensory, behavioural or cognitive states, and for the visual system a number of hypotheses have been proposed based on synchronized activity of different populations of neurons . A prerequisite for the type of synchronisation suggested is that visual stimuli are capable of affecting (resetting) the phase of brain oscillations. A change in the phase of brain waves assumingly also occurs in the “Berger effect” : If observers open their eyes, the amplitude of EEG oscillations in the alpha band (8 13 Hz) decreases or disappears completely. One interpretation is that due to visual stimulation oscillations in different neurons or neuronal populations are desynchronised. For a functional interpretation of brain oscillations it therefore seems crucial to nd out whether or not the phase of these brain oscillations can be affected by visual stimuli. To answer this question one has to examine whether brain waves are generated by linear or nonlinear mechanisms. If they are due to linear band pass ltering or linear oscillators, no phase resetting is possible, as the superposition law holds: the response to a stimulus is just superimposed on the ongoing oscillation, no phase resetting is possible. In contrast, in nonlinear oscillators (as described e.g. by the van der Pol equation), phases can be reset e.g. by an impulse. We analysed the question of linearity of alpha waves by investigating whether or not the superposition law holds: Light ashes were presented randomly, as usual, or at particular phases of the alpha waves. The result: the evoked potential to a ash, given at a particular phase, basically is the superposition of the alpha wave and the evoked potential to ashes presented randomly (which is without alpha contribution). This holds only, however, if one assumes that within 200 to 300 ms after a light ash the amplitude of alpha waves decreases in a ash intensity dependent degree. Conclusion: the phase of alpha, perhaps also of gamma waves cannot be reset by visual stimuli. This questions existing theories about the function of these waves. The “Berger effect” is not due to event related de- synchronisation. The amplitude of alpha waves after a ash are reduced in the same way as that of evoked potentials, due to the loss of sensitivity by light adaptation. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.twk.tuebingen.mpg.de/twk04/index.php Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 7th Tübingen Perception Conference (TWK 2004) kunoKKirschfeld poster 1058 2001 11 31 188.2 It has been reported that members of remote cultures, who are not familiar with pictorial materials, do not recognize pictures of familiar objects effortlessly. Moreover, the same perceptual cues are interpreted differently by subjects with different exposure to pictorial representations. In addition, familiarity with pictures, as a means of symbolic representation, is a more important factor in recognition than familiarity with depicted objects (Deregowski et al., Perception 1972). Although research of primate recognition often employs monkeys performing tasks with pictures shown on computer screens, it is not clear if the monkeys perceive the pictures as symbolic representations of familiar objects. We trained two macaque monkeys to perform a categorization task following standard operant conditioning techniques with positive reinforcement. The images (n=210) were sorted by natural category (n=18), included natural and man-made objects and were presented on a computer screen. During the training phase the monkeys were familiarized with a subset of images and learned by trial-and-error to respond by pulling one of two levers. Training with as few as three exemplars was typically enough for the monkeys to be able to generalize to new members of a category. Moreover, the monkeys were able to generalize to abstract representations. No significant differences were found for learning natural vs. man-made objects. These findings support the conclusion that macaques are able to extract similarities and form equivalence classes for objects they have no experience with, while familiarity with the depicted objects does not seem to facilitate learning of their pictorial representations. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Department Logothetis http://www.sfn.org/index.aspx?pagename=abstracts_ampublications Biologische Kybernetik Max-Planck-Gesellschaft San Diego, CA, USA 31st Annual Meeting of the Society for Neuroscience (Neuroscience 2001) kunoKKirschfeld natashaNSigala nikosNKLogothetis poster 304 1999 2 75 Ein Grundphänomen in der Psychophysik ist die Abhängigkeit der einfachen Reaktionszeit von der Reizstärke: sie nimmt mit abnehmender Intensität zu. Hierbei ist unklar, wo im sensomotorischen System die zeitliche Verzögerung entsteht. Denkbar ist einerseits eine intensitätsabhängige Verzögerung ausschliesslich auf der Eingangsseite. Alternativ dazu könnte eine intensitätsabhängige, zeitkonsumierende Integration des Eingangssignals auch auf jeder Verarbeitungsstufe vom Sensor bis zur Motorik stattfinden http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.twk.tuebingen.mpg.de/twk99/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 2. Tübinger Wahrnehmungskonferenz (TWK 99) kammerTKammer lehrLLehr kunoKKirschfeld poster 280 1998 2 143 function of the interstimulus interval (ISI) between target and surrounding mask. We hypothesized that there might be an increase in latency of perception along with reduction of perceived intensity. We displayed two horizontal bars (in one line, height: 0.5 deg, width 3 deg) on a PC monitor, each for 25 ms with a variable ISI, the left one was presented first. To achieve maximal metacontrast there was no gap at the neighbored edges of the two bars. Subjects perceive two moving lines, both start at the left and seem to ‚grow‘ to the right. The motion seen in the right line is the well known line motion illusion, generated by cue induced visual focal attention (Steinemann et al. 1997). The motion illusion perceived in the left line is due to metacontrast. This conclusion is supported by the finding that the effect is strongest when the left line as a target is presented 40 - 80 ms before the right line acting as a mask. At equivalent time differences, metacontrast in classical paradigms is strongest. The motion illusion results from the fact that the degree of dimming and the prolongation of latency decreases as the distance separating target from mask increases. There is a close relationship between metacontrast and cue induced focal attention, both show, however, opposite actions: Focal attention intensifies perception of an object and reduces its latency of perception, whereas metacontrast diminishes intensity and prolongs latency. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.twk.tuebingen.mpg.de/twk98/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 1. Tübinger Wahrnehmungskonferenz (TWK 98) kunoKKirschfeld kammerTKammer poster 279 1998 2 160 Transkranielle Magnetstimulation (TMS) des visuellen Kortex führt bei vielen Versuchspersonen (VP) zurWahrnehmung einfacher Phosphene. Andererseits kann TMS in einem umschriebenen Zeitfenster die visuelle Wahrnehmung unterdrücken. Bisher ist es unklar, ob die Lage der Phosphene im Sehfeld sich mit der Lage der Skotome deckt. Das Gesichtsfeld des rechten Auges von 10 VP wurde mit einem Raster von 32 Punkten perimetriert, die einen Abstand von 1 Grad, 4 Grad und 10 Grad vom Fixationspunkt hatten. Zusätzlich wurde der blinde Fleck mit 5 Punkten (Kontrollmessungen) bzw. 1 Punkt (TMS-Messungen) als Fixationskontrolle untersucht. Als Objekt diente ein Quadrat mit einer Seitenlänge von 0,25 Grad, welches für 1 ms auf einem Monitor mit einer Hintergrundshelligkeit von 2,9 cd/m2 gezeigt wurde. Die Wahrnehmungsschwellen wurden nach der Strategie des Tübinger Automatik-Perimeters mit individuellen Treppenfunktionen ermittelt. Über dem Occipitalpol der VP mit einer seitlichen Abweichung von der Mittellinie (1-2 cm) wurde TMS mit einer fokalen Doppelspule und einer Intensität von 50-75% der maximalen Ausgangsleistung appliziert. Die VP zeichneten die wahrgenommenen Phosphene auf ein Amsler-Netz. Zur Perimetrie unter TMS wurde mit einer festgewählten SOA von 70-100 ms nach jeder Präsentation ein Magnetpuls ausgelöst. Alle 10 VP konnten Phosphene beschreiben, die sich je nach Spulenposition überwiegend in den kontralateralen unteren Quadranten parafoveal mit 1 Grad - 5 Grad ausdehnten. Das Ausmaß der Phosphene variierte interindividuell und war in kritischer Weise abhängig von der Spulenposition. Bei 8 von 10 VP fand sich unter TMS eine Erhöhung der Wahrnehmungsschwellen von 8 - 18 dB in den Gesichtsfeldbereichen, in denen die VP das Phosphen wahrgenommen hatte. Die Winkelgröße des Skotoms stimmte bei vier VP mit der des Phosphens überein, bei einer war das Skotom kleiner und bei dreien größer. Fokale TMS über dem visuellen Kortex führt zur Modulation der Wahrnehmungsschwellen im Sinne eines transienten Skotoms. Es besteht eine topographische Korrespondenz zwischen den durch Magnetstimulation evozierbaren umschriebenen Phosphenen und den transienten Skotomen. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.twk.tuebingen.mpg.de/twk98/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 1. Tübinger Wahrnehmungskonferenz (TWK 98) kammerTKammer kunoKKirschfeld poster 271 1998 2 137 The visual system consists of several subsystems, which perform their task nearly independently of each other. One is the accessory-optic system, performing the gaze stabilisation by eye-nystagmus. In humans two kinds of nystagmus can be discriminated: stare nystagmus and look nystagmus (smooth pursuit). The best known example for stare nystagmus can be seen on a train journey. The vis-à-vis -staring out of the window- moves his eyes nystagmic. Without fixating any single object the eyes run over the landscape, most of the time following and bouncing back every now and then. In contrast, during look nystagmus single objects are fixated and pursued. Stare nystagmus is driven by the accessory-optic system, a set of subcortical nuclei, while cortical structures contribute to the look nystagmus. In order to find out which cones contribute to both kinds of nystagmus, we measured their spectral sensitivity. Two different instructions were given to the observers, leading to either stare or look nystagmus, respectively. Spectral sensitivity turned out to be different for look and stare nystagmus. Spectral sensitivity of stare nystagmus corresponds basically to the V(l)-function, indicating that there is no or only a minor contribution of the short wavelength cones. Look nystagmus has a higher sensitivity at short wavelengths, demonstrating a contribution of short wavelength cones. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.twk.tuebingen.mpg.de/twk98/ Biologische Kybernetik Max-Planck-Gesellschaft Tübingen, Germany 1. Tübinger Wahrnehmungskonferenz (TWK 98) MCampenhausen kunoKKirschfeld poster 397 Neuroscience Letters 1997 12 Supplement 48 S12 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.sciencedirect.com/science/article/pii/S0304394097900483 Biologische Kybernetik Max-Planck-Gesellschaft Eilat, Israel Sixth Annual Meeting of the Israel Society for Neurosciences 10.1016/S0304-3940(97)90048-3 MCampenhausen kunoKKirschfeld poster 396 From Membrane to Mind 1997 5 616 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 25th Göttingen Neurobiology Conference antkowiaBAntkowiak CHelfrich-Förster inaIPappe kunoKKirschfeld poster 579 Brain and Evolution 1996 5 2 428 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 24th Göttingen Neurobiology Conference kunoKKirschfeld poster 590 Brain and Evolution 1996 5 2 386 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 24th Göttingen Neurobiology Conference SSchaerer feilerRFeiler kunoKKirschfeld poster 578 Neuroforum 1996 2 2 Sonderausgabe 166 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany 1. Kongress der Neurowissenschaftlichen Gesellschaft kunoKKirschfeld poster 589 Neuroforum 1996 2 2 Sonderausgabe 194 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Berlin, Germany 1. Kongress der Neurowissenschaftlichen Gesellschaft SSchaerer feilerRFeiler kunoKKirschfeld poster 1275 New Frontiers in Brain Research 1987 148 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Götz Biologische Kybernetik Max-Planck-Gesellschaft Göttingen, Germany 15th Göttingen Neurobiology Conference MGewecke kunoKKirschfeld feilerRFeiler EHartwieg hbgRHengstenberg GLenz poster 3749 Verhandlungen der Deutschen Zoologischen Gesellschaft 1983 5 76 330 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Verhandlungen der Deutschen Zoologischen Gesellschaft Biologische Kybernetik Max-Planck-Gesellschaft Bonn, Germany 76. Jahresversammlung der Deutschen Zoologischen Gesellschaft 3-437-30443-7 KVogt kunoKKirschfeld poster 3745 Verhandlungen der Deutschen Zoologischen Gesellschaft 1982 6 75 337 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Hannover, Germany 75. Jahresversammlung der Deutschen Zoologischen Gesellschaft KVogt kunoKKirschfeld poster 3718 Verhandlungen der Deutschen Zoologischen Gesellschaft 1977 6 70 229 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft Erlangen, Germany 70. Jahresversammlung der Deutschen Zoologischen Gesellschaft kunoKKirschfeld BMinke NFranceschini poster 3392 Information Processing in the Nervous System 1962 9 2 977 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Reichardt Biologische Kybernetik Max-Planck-Gesellschaft MPI f. biol. Kybernetik, Tübingen Leiden, Netherlands XXII International Congress of Physiological Sciences kunoKKirschfeld miscellaneous 4773 Diskussionsbeitrag für den Landesbeirat für Tierschutz des Landes Baden-Württemberg 2007 6 2007 1-7 http://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/StellungnahmeKirschfeld15-06-07_[0].pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld miscellaneous 1201 Schwäbisches Tagblatt 2001 12 1 30 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.cityinfonetz.de/tagblatt/archiv/2001/12/03/text4b.phtml Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld miscellaneous 142 Süddeutsche Zeitung 2001 11 17 265 II http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld Biologische Kybernetik Max-Planck-Gesellschaft kunoKKirschfeld miscellaneous 6258 Die Zeit 1991 8 1991 35 1-5 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.zeit.de/1991/35/Eine-Zelle-ist-noch-kein-Mensch Biologische Kybernetik Max-Planck-Gesellschaft de kunoKKirschfeld conference Kirschfeld1996 Perception 1996 9 25 ECVP Abstract Supplement 2 The point spread in visual cortex (the area of the cortex activated by a minimal visual stimulus) measured by optical recording is very much larger than the point spread measured by spike activity; it develops more slowly and lasts for a longer time (Grinvald et al, 1994 Journal of Neuroscience 14 2545 -- 2568). It is considered to reflect mainly subthreshold activity of neuronal arborisations. It is shown how this subthreshold activity may contribute to information processing: the sudden onset of a visual cue is known to trigger visual attention, which then enhances visual processing in the zone near the cue. The most likely physiological basis of attention is a subthreshold wave of negativity. This wave develops more slowly than signals leading to perception, and spreads outward from the cortical region associated with the cue, into regions associated with other retinal sites. Such slow potentials are known to influence behavioural responses: negativity reduces neuronal thresholds and hence shortens response latencies (Birbaumer et al, 1990 Physiological Reviews 70 1 -- 41). As examples, the line motion illusion and the generation of express saccades are discussed on the basis of this concept. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Kirschfeld http://www.perceptionweb.com/abstract.cgi?id=v96l0104 Strasbourg, France 19th European Conference on Visual Perception kunoKKirschfeld