% % This file was created by the Typo3 extension % sevenpack version 0.7.14 % % --- Timezone: CEST % Creation date: 2013-05-23 % Creation time: 21-40-53 % --- Number of references % 39 % @Article { LogothetisEMASEBO2012, title = {Hippocampal-cortical interaction during periods of subcortical silence}, journal = {Nature}, year = {2012}, month = {11}, volume = {491}, number = {7425}, pages = {547–553}, abstract = {Hippocampal ripples, episodic high-frequency field-potential oscillations primarily occurring during sleep and calmness, have been described in mice, rats, rabbits, monkeys and humans, and so far they have been associated with retention of previously acquired awake experience. Although hippocampal ripples have been studied in detail using neurophysiological methods, the global effects of ripples on the entire brain remain elusive, primarily owing to a lack of methodologies permitting concurrent hippocampal recordings and whole-brain activity mapping. By combining electrophysiological recordings in hippocampus with ripple-triggered functional magnetic resonance imaging, here we show that most of the cerebral cortex is selectively activated during the ripples, whereas most diencephalic, midbrain and brainstem regions are strongly and consistently inhibited. Analysis of regional temporal response patterns indicates that thalamic activity suppression precedes the hippocampal population burst, which itself is temporally bounded by massive activations of association and primary cortical areas. These findings suggest that during off-line memory consolidation, synergistic thalamocortical activity may be orchestrating a privileged interaction state between hippocampus and cortex by silencing the output of subcortical centres involved in sensory processing or potentially mediating procedural learning. Such a mechanism would cause minimal interference, enabling consolidation of hippocampus-dependent memory.}, department = {Department Logothetis}, web_url = {http://www.nature.com/nature/journal/v491/n7425/full/nature11618.html}, DOI = {10.1038/nature11618}, author = {Logothetis, NK and Eschenko, O and Murayama, Y and Augath, M and Steudel, T and Evrard, HC and Besserve, M and Oeltermann, A} } @Article { EvrardFL2012_2, title = {Von economo neurons in the anterior insula of the macaque monkey}, journal = {Neuron}, year = {2012}, month = {5}, volume = {74}, number = {3}, pages = {482–489}, abstract = {The anterior insular cortex (AIC) and its unique spindle-shaped von Economo neuron (VEN) emerged within the last decade as having a potentially major role in self-awareness and social cognition in humans. Invasive examination of the VEN has been precluded so far by the assumption that this neuron occurs among primates exclusively in humans and great apes. Here, we demonstrate the presence of the VEN in the agranular anterior insula of the macaque monkey. The morphology, size, laminar distribution, and proportional distribution of the monkey VEN suggest that it is at least a primal anatomical homolog of the human VEN. This finding sheds new light on the phylogeny of the VEN and AIC. Most importantly, it offers new and much-needed opportunities to investigate the primal connections and physiology of a neuron that could be crucial for human self-awareness, social cognition, and related neuropsychiatric disorders.}, department = {Department Logothetis}, web_url = {http://www.sciencedirect.com/science/article/pii/S0896627312002267}, DOI = {10.1016/j.neuron.2012.03.003}, author = {Evrard, HC and Forro, T and Logothetis, NK} } @Article { EschenkoENBML2011, title = {Tracing of noradrenergic projections using manganese-enhanced MRI}, journal = {NeuroImage}, year = {2012}, month = {2}, volume = {59}, number = {4}, pages = {3252–3265}, abstract = {We examined the applicability of manganese-enhanced MRI (MEMRI) to the in vivo tracing of diffuse neuromodulatory projections by means of simultaneous iontophoretic injections of an extremely low, non-toxic concentration of MnCl2 (10 mM) and fluorescent dextran in the locus coeruleus (LC) in the rat. We validated the use of the iontophoretic injection by reproducing previously reported results from pressure injections of MnCl2 in primary somatosensory cortex. Twenty four hours after injection in LC, Mn2 + labeling was detected in major cortical and subcortical targets of LC projections including predominantly ipsilateral primary motor and somatosensory cortices, hippocampus and amygdala. Although the injections were in most cases centered in the core of LC, the pattern of Mn2 + labeling greatly varied across rats. In addition, despite a certain degree of overlap of the labeling obtained with both MEMRI and classical tracing, MEMRI tracing consistently failed to reliably label not only several minor but also major targets of LC, notably the thalamus. The lack of Mn2 + labeling in thalamus possibly reflected a weaker functional connectivity within coeruleothalamic projections that could not be predicted by anatomical tracing. Inversely, a number of brain regions, particularly contralateral motor cortex, that were not or only sparsely labeled with fluorescent dextran were strongly labeled by Mn2 +. This discrepancy could be partly due to both the activity-dependent and transsynaptic nature of Mn2 + transport. The overall labeling produced using MEMRI with iontophoretic injections in LC indicates that the Mn2 + imaging of highly diffuse projections is in principle feasible. However, the labeling pattern of each individual case needs to be carefully interpreted particularly before submitting data for group analysis or in the case of longitudinal examination of discrete changes in functional connectivity under various physiological or behavioral conditions.}, department = {Department Logothetis}, web_url = {http://www.sciencedirect.com/science/article/pii/S1053811911013127}, DOI = {10.1016/j.neuroimage.2011.11.031}, author = {Eschenko, O and Evrard, HC and Neves, RM and Beyerlein, M and Murayama, Y and Logothetis, NK} } @Article { EvrardC2008, title = {Retrograde analysis of the cerebellar projections to the posteroventral part of the ventral lateral thalamic nucleus in the macaque monkey}, journal = {Journal of Comparative Neurology}, year = {2008}, month = {5}, volume = {508}, number = {2}, pages = {286–314}, abstract = {The organization of cerebellothalamic projections was investigated in macaque monkeys using injections of retrograde tracers (cholera toxin B and fluorescent dextrans) in the posteroventral part of the ventrolateral thalamic nucleus (VLpv), the main source of thalamic inputs to the primary motor cortex. Injections that filled all of VLpv labeled abundant neurons that were inhomogeneously distributed among many unlabeled cells in the deep cerebellar nuclei (DCbN). Single large pressure injections made in face-, forelimb-, or hindlimb-related portions of VLpv using physiological guidance labeled numerous neurons that were broadly dispersed within a coarse somatotopographic anteroposterior (foot to face) gradient in the dentate and interposed nuclei. Small iontophoretic injections labeled fewer neurons with the same somatotopographic gradient, but strikingly, the labeled neurons in these cases were as broadly dispersed as in cases with large injections. Simultaneous injections of multiple tracers in VLpv (one tracer per somatic region with no overlap between injections) confirmed the general somatotopography but also demonstrated clearly the overlapping distributions and the close intermingling of neurons labeled with different tracers. Significantly, very few neurons (<2\%) were double-labeled. This organizational pattern contrasts with the concept of a segregated “point-to-point” somatotopy and instead resembles the complex patterns that have been observed throughout the motor pathway. These data support the idea that muscle synergies are represented anatomically in the DCbN by a general somatotopography in which intermingled neurons and dispersed but selective connections provide the basis for plastic, adaptable movement coordination of different parts of the body.}, web_url = {http://onlinelibrary.wiley.com/doi/10.1002/cne.21674/pdf}, DOI = {10.1002/cne.21674}, author = {Evrard, HC and Craig, AD} } @Article { Evrard2006, title = {Estrogen synthesis in the spinal dorsal horn: a new central mechanism for the hormonal regulation of pain}, journal = {American Journal of Physiology: Regulatory, Integrative and Comparative Physiology}, year = {2006}, month = {8}, volume = {291}, number = {2}, pages = {R291-R299}, abstract = {The data summarized here suggest the existence of a new central pathway for the hormonal regulation of pain. These data mainly collected in quail, a useful model in neuroendocrinology, demonstrate that numerous neurons in the superficial laminae of the spinal cord express aromatase (estrogen-synthase). Chronic and systemic blockade of this enzyme in quail alters nociception within days, indicating that the slow genomic effects of sex steroids on nociception classically observed in mammals also occur in birds and require aromatization of androgens into estrogens. However, by contrast with these slow effects, acute intrathecal inhibition of aromatase in restricted spinal cord segments reveals that estrogens can also control nociception much faster, within 1 min, presumably through the activation of a nongenomic pathway and in a manner that depends on an immediate response to fast activation/deactivation of local aromatase activity. This emergent central and rapid paracrine mechanism might permit instantaneous and segment-specific changes in pain sensitivity; it draws new interesting perspectives for the study of the estrogenic control of pain, thus far limited to the classical view of slow genomic changes in pain, depending on peripheral estrogens. The expression of aromatase in the spinal cord in other species and in other central nociception-related areas is also briefly discussed.}, web_url = {http://ajpregu.physiology.org/content/291/2/R291.long}, DOI = {10.1152/ajpregu.00930.2005}, author = {Evrard, HC} } @Article { EvrardB2004, title = {Rapid Regulation of Pain by Estrogens Synthesized in Spinal Dorsal Horn Neurons}, journal = {Journal of Neuroscience}, year = {2004}, month = {8}, volume = {24}, number = {33}, pages = {7225-7229}, abstract = {In addition to exerting genomic actions via nuclear receptors within hours to days, estrogens also regulate neuronal activity much faster (within seconds) by activating neuronal membrane receptors coupled to intracellular second-messenger pathways. To date, the origin of estrogens inducing rapid effects in the brain remains unclear, although it is often ascribed to the gonads. We report here that an acute blockade of the endogenous synthesis of estrogens in the quail spinal dorsal horn markedly reduced, within 1 min, the behavioral responsiveness to a thermal painful stimulus. Similar rapid effects in the opposite direction were induced by estradiol. This finding identifies a new paracrine and nongenomic mechanism for the regulation of pain by estrogens. Such regulation was assumed previously to result only from slow genomic actions of estrogens arising from the ovaries. Also, quite importantly, this finding suggests that the numerous rapid nongenomic effects of estrogens in the CNS could depend on their immediate local production by the enzyme aromatase, independently from the gonads.}, web_url = {http://www.jneurosci.org/content/24/33/7225.full.pdf+html}, DOI = {10.1523/JNEUROSCI.1638-04.2004}, author = {Evrard, HC and Balthazart, J} } @Article { HauDE2004, title = {Testosterone reduces responsiveness to nociceptive stimuli in a wild bird}, journal = {Hormones and Behavior}, year = {2004}, month = {8}, volume = {46}, number = {2}, pages = {165-170}, abstract = {The hormone testosterone (T) is involved in the control of aggressive behavior in male vertebrates. T enhances the frequency and intensity of aggressive behaviors during competitive interactions among males. By promoting high-intensity aggression, T also increases the risk of injury and presumably the perception of painful stimuli. However, perception of painful stimuli during fights could counteract the expression of further aggressive behavior. We therefore hypothesize that one function of T during aggressive interactions is to reduce nociception (pain sensitivity). Here, we experimentally document that T indeed reduces behavioral responsiveness to a thermal painful stimulus in captive male house sparrows (Passer domesticus). Skin nociception was quantified by foot immersion into a hot water bath, a benign thermal stimulus. Males treated with exogenous testosterone left their foot longer in hot water than control birds. Conversely, males in which the physiological actions of testosterone were pharmacologically blocked withdrew their foot faster than control birds. Testosterone might exert its effects on pain sensitivity through conversion into estradiol in the dorsal horn of the spinal cord. Decreased nociception during aggressive encounters may promote the immediate and future willingness of males to engage in high-intensity fights.}, web_url = {http://www.sciencedirect.com/science?_ob=MiamiImageURL\&_cid=272297\&_user=29041\&_pii=S0018506X04000911\&_check=y\&_origin=browse\&_coverDate=31-Aug-2004\&view=c\&wchp=dGLbVBA-zSkzS\&md5=fa53f9d2cb44a8ec1be926df235f9a52/1-s2.0-S0018506X04000911-main.pdf}, DOI = {10.1016/j.yhbeh.2004.02.007}, author = {Hau, M and Dominguez, OA and Evrard, HC} } @Article { EvrardHB2004, title = {Immunocytochemical localization of aromatase in sensory and integrating nuclei of the hindbrain in Japanese quail (Coturnix japonica)}, journal = {Journal of Comparative Neurology}, year = {2004}, month = {5}, volume = {473}, number = {2}, pages = {194–212}, abstract = {The distribution of the estrogen synthesizing enzyme (aromatase) in the hindbrain (rhombencephalon and mesencephalon) of male adult quail was investigated by immunocytochemistry. Aromatase-immunoreactive neuronal structures (perikarya and fibers bearing punctate structures) were observed in sensory (trigeminal, solitary tract, vestibular, optic tectum) and integrating (parabrachial, periaqueductal, cerulean, raphe) nuclei. Besides the expression of aromatase in these well-delineated nuclei, dense to scattered networks of immunoreactive fibers were found dispersed throughout the hindbrain and, in particular, in its rostral and dorsal parts. To a lesser extent, they were also present throughout the premotor nuclei of the reticular formation and in various fiber tracts. In contrast, no immunoreactive signal was found in motor nuclei, and in most of the statoacoustic (cerebellum, cochlear, olive, pontine, part of vestibular) nuclei. The expression of aromatase in perikarya and fibers in areas of the adult hindbrain where estrogen receptors have been identified previously suggests a role for estrogens locally produced in the regulation of sensory and integrating functions, contrary to the widespread assumption that these functions are regulated exclusively by steroids produced in the gonads.}, web_url = {http://onlinelibrary.wiley.com/doi/10.1002/cne.20068/pdf}, DOI = {10.1002/cne.20068}, author = {Evrard, HC and Harada, N and Balthazart, J} } @Article { EvrardB2004_2, title = {Aromatization of androgens into estrogens reduces response latency to a noxious thermal stimulus in male quail}, journal = {Hormones and Behavior}, year = {2004}, month = {3}, volume = {45}, number = {3}, pages = {181-189}, abstract = {We recently demonstrated the presence of estrogen synthase (aromatase) and of estrogen receptors in the dorsal horn (laminae I–II) throughout the rostrocaudal extent of the spinal cord in male and female Japanese quail. The spinal laminae I–II receive and process abundant sensory information elicited, among others, by acute noxious stimulation of the skin and resulting in rapid, reflex-like withdrawal behavior. In the present study, we demonstrate that systemic treatment with estradiol or testosterone markedly decreases the latency of the foot withdrawal in the hot water test. A simultaneous treatment with an aromatase inhibitor blocks the effects of testosterone demonstrating, hence, that they are mediated by a conversion of testosterone into an estrogen by aromatase. Furthermore, the testosterone- or estradiol-induced decrease in foot withdrawal latency is blocked by a treatment with the estradiol receptor antagonist, tamoxifen, indicating that the effects are largely mediated by the interaction of estradiol with estrogen receptors. Together, these data suggest that sex steroids modulate sensitivity to noxious stimuli possibly by a direct action at the level of the dorsal horn of the spinal cord.}, web_url = {http://www.sciencedirect.com/science?_ob=MiamiImageURL\&_cid=272297\&_user=29041\&_pii=S0018506X04000054\&_check=y\&_origin=\&_coverDate=31-Mar-2004\&view=c\&wchp=dGLzVlk-zSkzS\&md5=4ef139567c76bd18984a41b10cdb7e2b/1-s2.0-S0018506X04000054-main.pdf}, DOI = {10.1016/j.yhbeh.2003.09.014}, author = {Evrard, HC and Balthazart, J} } @Article { EvrardB2003, title = {Aromatase (Estrogen Synthase) Activity in the Dorsal Horn of the Spinal Cord: Functional Implications}, journal = {Annals of the New York Academy of Sciences}, year = {2003}, month = {12}, volume = {1007}, pages = {263–271}, abstract = {The presence of aromatase (estrogen synthase) in neurons in the dorsal horn of the spinal cord in Japanese quail suggests that estrogens produced locally from androgens could control spinal sensory processes including nociception. We used the hot water nociceptive test (54\(^{\circ}\)C) to appraise the long-term effect of an inhibition of aromatization on the foot withdrawal latency in male quail. Four weeks after the ablation of their main source of testosterone (testes), castrated males displayed a significantly higher foot withdrawal latency than gonadally intact males. A prolonged treatment with subcutaneous capsules filled with testosterone or 17 beta-estradiol restored the baseline latency within 2 weeks. The effect of testosterone in castrated quail was almost completely blocked by systemic injections of Vorozole™, a nonsteroidal aromatase inhibitor or tamoxifen, an estrogen receptor antagonist (one injection per day for 10 days). Taken together, these data demonstrate for the first time to our knowledge an effect of estrogens formed by aromatization of androgens on nociception. Because aromatase-immunoreactive neurons and aromatase activity are present in the dorsal horns of the spinal cord, this control of pain thresholds is presumably mediated, at least in part, by estrogens produced at the spinal level that act locally via slow, presumably genomic, mechanisms mediated by the activation of spinal nuclear estrogen receptors.}, web_url = {http://onlinelibrary.wiley.com/doi/10.1196/annals.1286.025/pdf}, DOI = {10.1196/annals.1286.025}, author = {Evrard, HC and Balthazart, J} } @Article { EvrardWHB2003, title = {Specific innervation of aromatase neurons by substance P fibers in the dorsal horn of the spinal cord in quail}, journal = {Journal of Comparative Neurology}, year = {2003}, month = {10}, volume = {465}, number = {2}, pages = {309-318}, abstract = {The enzyme aromatase catalyzes the production of estrogens in the dorsal horn of the spinal cord where most of the nociceptive primary afferent fibers terminate. Numerous estrogen receptors are present in this area and the control of spinal aromatase activity is thought to play an important role in the estrogenic control of nociception. The coexistence of aromatase and nociceptive terminals suggests a role for aromatase cells in pain-related processes, but whether terminals releasing nociceptive neuropeptides (e.g., substance P) actually contact aromatase neurons is unknown and the factors that control spinal aromatase activity have not yet been identified. In the present study we analyzed by double-label immunocytochemistry the distribution in the Japanese quail spinal cord, of aromatase and of substance P or its receptor (neurokinin 1 receptor). All antigens were mainly localized in laminae I and II as observed in mammals. Most aromatase neurons were colocalized with neurokinin 1 receptors and were in close apposition with substance P-immunoreactive fibers. These results suggest that aromatase neurons are responsive to noxious stimulation and may participate in the control of nociception. Furthermore, spinal aromatase activity could be controlled by substance P through a regulation of the aromatase gene transcription as reported for the mouse diencephalon and/or through neurokinin 1 receptor-dependent phosphorylation of the aromatase protein.}, web_url = {http://onlinelibrary.wiley.com/doi/10.1002/cne.10854/pdf}, DOI = {10.1002/cne.10854}, author = {Evrard, HC and Willems, E and Harada, N and Balthazart, J} } @Article { EvrardB2002, title = {Localization of Oestrogen Receptors in the Sensory and Motor Areas of the Spinal Cord in Japanese Quail (Coturnix japonica)}, journal = {Journal of Neuroendocrinology}, year = {2002}, month = {11}, volume = {14}, number = {11}, pages = {894–903}, abstract = {In Japanese quail, the presence of aromatase (oestrogen synthase) in the dorsal horn of the spinal cord suggests that spinal sensory processes might be controlled by local actions of oestrogens. This is supported by the presence of oestrogen receptors and aromatase in the dorsal horn of the spinal cord in rats, and by the alteration of sensitivity by oestrogens in various mammalian species and also in canaries. We investigated whether oestrogens that are locally produced in the quail spinal cord can bind to specific receptors in the vicinity of their site of synthesis. We demonstrate the presence of numerous oestrogen receptor \(\alpha\)-immunoreactive (ER\(\alpha\)-ir) cell nuclei, predominantly in laminae II and, to a lesser extent, I and III of the dorsal horn of the spinal cord (i.e. in the area where aromatase was previously identified). ER\(\alpha\)-ir cells were also seen in various parts of the intermediate zone (laminae V–VII). This presence of ER\(\alpha\)-ir cells in the dorsal horn and intermediate zone fits in well with the distribution of ER\(\alpha\)-ir cells in homologous areas in mammals, including rats. Only a few labelled cells were found in the ventral horn in the cervical, brachial, thoracic and first lumbar segments, but a conspicuous dense group of large ER\(\alpha\)-ir cells was identified in lamina IX of the ventral horn in synsacral segments 8–10, which contain the motoneurones innervating the muscles of the cloacal gland. The presence of ER\(\alpha\)-ir cells in lamina IX of these synsacral segments in quail contrasts with the finding that motoneurones innervating penile muscles in rats contain androgen, but not oestrogen receptors, and are influenced by androgens rather than by oestrogens. Together, these data suggest that spinal actions of oestrogens may modulate the sensory and motor systems that participate in reproduction, as well as other nonreproductive functions in quail.}, web_url = {http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2826.2002.00857.x/pdf}, DOI = {10.1046/j.1365-2826.2002.00857.x}, author = {Evrard, HC and Balthazart, J} } @Article { EvrardB2002_2, title = {The assessment of nociceptive and non-nociceptive skin sensitivity in the Japanese quail (Coturnix japonica)}, journal = {Journal of Neuroscience Methods}, year = {2002}, month = {5}, volume = {116}, number = {2}, pages = {135-146}, abstract = {We evaluated the efficacy of two nociceptive tests, the hot water (HWT) and the foot pressure tests (FPT), and one non-nociceptive test (Semmes–Weinstein test, SWT) in assessing skin sensitivity in conscious Japanese quail. All stimuli elicited a reflex-like, strongly reproducible response. Responses in the HWT and FPT were identified as typical nocifensive flight-fight behavior. In untreated birds, these responses occurred at temperatures and forces described previously as noxious. In the SWT, two responses were observed: a slight ruffling of the cloacal gland feathers due to the stimulation of the cloacal gland, and a brief extension of the limbs due to the stimulation of the ilium or pectoral apterium. These reactions occurred at intensities recognized as innocuous. Morphine significantly altered the response latency and threshold in the HWT and FPT, but had no effect in the SWT. However, the SWT response threshold was significantly increased by local application of xylocaine. Taken together, the pattern of the responses, the intensities and the effects of morphine and xylocaine allowed to distinguish between nociceptive and non-nociceptive tests. They also demonstrate the efficacy of these tests to evaluate skin sensitivity in quail and to assess its modulation by chemical factors that affect somatosensory processes.}, web_url = {http://www.sciencedirect.com/science?_ob=MiamiImageURL\&_cid=271055\&_user=29041\&_pii=S0165027002000341\&_check=y\&_origin=\&_coverDate=15-May-2002\&view=c\&wchp=dGLzVlB-zSkWA\&md5=28a9e13e4bd5ca998c415c18586c0f2c/1-s2.0-S0165027002000341-main.pdf}, DOI = {10.1016/S0165-0270(02)00034-1}, author = {Evrard, HC and Balthazart, J} } @Article { EvrardBAFB2000, title = {Localization and controls of aromatase in the quail spinal cord}, journal = {Journal of Comparative Neurology}, year = {2000}, month = {8}, volume = {423}, number = {4}, pages = {552–564}, abstract = {In adult male and female Japanese quail, aromatase-immunoreactive cells were identified in the spinal dorsal horns from the upper cervical segments to the lower caudal area. These immunoreactive cells are located mostly in laminae I–III, with additional sparse cells being present in the medial part of lamina V and, at the cervical level exclusively, in lamina X around the central canal. Radioenzyme assays based on the measurement of tritiated water release confirmed the presence of substantial levels of aromatase activity throughout the rostrocaudal extent of the spinal cord. Contrary to what is observed in the brain, this enzyme activity and the number of aromatase-immunoreactive cells in five representative segments of the spinal cord are not different in sexually mature males or females and are not influenced in males by castration with or without testosterone treatment. The aromatase activity and the numbers of aromatase-immunoreactive cells per section are higher at the brachial and thoracic levels than in the cervical and lumbar segments. These experiments demonstrate for the first time the presence of local estrogen production in the spinal cord of a higher vertebrate. This production was localized in the sensory fields of the dorsal horn, where estrogen receptors have been identified previously in several avian and mammalian species, suggesting an implication of aromatase in the modulation of sensory (particularly nociceptive) processes.}, web_url = {http://onlinelibrary.wiley.com/doi/10.1002/1096-9861(20000807)423:4\%3C552::AID-CNE2\%3E3.0.CO;2-S/pdf}, DOI = {10.1002/1096-9861(20000807)423:4<552::AID-CNE2>3.0.CO;2-S}, author = {Evrard, HC and Baillien, M and Absil, A and Foidart, A and Balthazart, J} } @Inbook { BalthazartBCCEB2005, title = {Behavioral Effects of rapid Changes in Aromatase Activity in the Central Nervous System}, year = {2005}, pages = {173-199}, abstract = {In many vertebrate species, male sexual behavior is activated by the action in the preoptic area of estrogens produced by the local aromatization of testosterone. Estrogens bind to intracellular receptors, which then act as transcription factors to activate the behavior. In parallel, changes in aromatase activity (AA) result from steroid-induced modifications of enzyme transcription. The transcription of aromatase is regulated in a synergistic manner by estrogenic and androgenic metabolites of testosterone. Regulatory proteins such as the steroid receptor coactivator-1 modulate steroid action in the brain, and an increasing amount of data now indicate that this mode of control is also implicated in the activation by steroids of sexual behavior and of aromatase transcription. More recently, rapid non-genomic effects of estrogens have been described in a variety of animal models, and evidence has accumulated in Japanese quail indicating that AA in the preoptic area is modulated by rapid (minute to hour) non-genomic mechanisms in addition to the slower (hours to days) transcriptional changes. Conditions that enhance protein phosphorylation, such as the presence of high concentrations of calcium, magnesium and ATP, rapidly (within min) downregulate AA in hypothalamic homogenates. Similarly, the pharmacological mobilization of intracellular calcium with thapsigargin or stimulation of various glutamate receptors (AMPA, kainate, NMDA) that lead to increased intracellular calcium concentrations depresses within minutes the AA that is measured in quail preoptic explants. Protein kinase inhibitors interfere with the calcium-induced inhibition of AA, and multiple phosphorylation consensus sites are present on the deduced amino acid sequence of quail aromatase. Fast changes in the local availability of estrogens in the brain can thus be caused by aromatase phosphorylations that rapidly regulate neuronal physiology and behavior. Recent studies suggest that the pharmacological blockade of AA by specific inhibitors rapidly down regulates motivational and consummatory aspects of male sexual behavior in quail and decreases responsiveness to painful stimuli within minutes. The rapid and slower changes of AA in the central nervous system thus match well with the genomic and non-genomic actions of estrogens and potentially provide temporal variations in the bioavailability of estrogens that can support the entire range of established effects for this steroid.}, web_url = {http://www.springerlink.com/content/g7612471k331333q/fulltext.pdf}, editor = {Kordon, C. , R.-C. Gaillard, Y. Christen}, publisher = {Springer}, address = {Berlin, Germany}, series = {Research and Perspectives in Endocrine Interactions}, booktitle = {Hormones and the Brain}, ISBN = {978-3-540-21355-0}, DOI = {10.1007/3-540-26940-1_10}, author = {Balthazart, J and Baillien, M and Cornil, CA and Charlier, TC and Evrard, HC and Ball, DF} } @Poster { KleinEPBLS2012, title = {Optogenetics in the macaque thalamus}, year = {2012}, month = {10}, volume = {42}, number = {610.09}, abstract = {Optogenetics is a potentially powerful tool to manipulate and map specific neural circuits. The few studies that have so far implemented this method in primates focused on the neocortex. Here, we transduced cells in multiple thalamic nuclei of one rhesus macaque with a DNA construct encoding the microbial proton-pump ArchT and the green fluorescent protein (GFP). A constitutively active promoter (CAG) was used to ensure high-level protein expression. Adeno associated virus (AAV2 or AAV5) was used to deliver the gene. Electrophysiological recordings were carried out under anesthesia six to eight weeks after the AAV injections. Continuous illumination with green light (532 nm) through an optic fiber (110 µm diameter) placed in the injected thalamic regions markedly and reliably reduced the local ongoing spiking activity (60\% on average) with fast recovery to baseline firing after light offset. Post-mortem stereological microscope examination indicated that \verb=~=25\% of the neurons in the thalamic injection sites were GFP-labeled and exhibited the typical large soma size and radial dendritic arborization characteristic of thalamocortical projection (TC) neurons. We also found dense GFP-labeled axon terminals in layers 3-4 in the cortical targets of the injected thalamic regions. In the TC soma, the GFP labeling was mostly localized at membrane sites with no accumulation in the cytoplasm and cell nucleus. Based on morphological analysis there was no obvious GFP labeling in local interneurons or in the glia. However, besides the apparently healthy TC neurons, we also observed a small percentage (\verb=~=5\%) of round GFP-labeled formations that had roughly the same diameter as the TC dendrite arborization (\verb=~=85 µm) but no recognizable neuropil or perikaryal morphology. These formations could be the remains of cells that degenerated after overexpressing the construct. These results show that AAV vectors can be used in the monkey thalamus for intra-neuronal delivery of opsin-encoding DNA sequences and reliable manipulation of neuronal activity. While further characterization of the extent and specificity of gene expression is necessary, intrathalamic injections of AAV vectors could provide the much-needed tool to examine separately and in great physiological and anatomical detail the intricately mingled components of the primate thalamocortical circuitry.}, department = {Department Logothetis}, web_url = {http://www.sfn.org/am2012/}, event_place = {New Orleans, LA, USA}, event_name = {42nd Annual Meeting of the Society for Neuroscience (Neuroscience 2012)}, author = {Klein, C and Evrard, HC and Power, AT and Boyden, ES and Logothetis, NK and Schmid, M} } @Poster { KleinEPBLS2012_2, title = {Optogenetics in the macaque thalamus}, year = {2012}, month = {10}, department = {Department Logothetis}, web_url = {http://www.brainresearchconference.com/}, event_place = {New Orleans, LA, USA}, event_name = {7th Brain Research Conference “Optogenetics and Pharmacogenetics in Neuronal Function and Dysfunction”}, state = {accepted}, author = {Klein, C and Evrard, HC and Power, AT and Boyden, ES and Logothetis, NK and Schmid, MC} } @Poster { EvrardFL2012_3, title = {Areal Distribution Of The Von Economo In The Anterior Insular And Anterior Cingulate Cortices In The Macaque Monkey}, year = {2012}, month = {7}, volume = {8}, number = {p136.23}, abstract = {The anterior insular (AIC) and anterior cingulate (ACC) cortices and their unique spindle-shaped von Economo neurons (VENs) emerged within the last decade as having a potentially major role in interoceptive, emotional and social awareness and cognition in humans. A role of the VENs in these fundamental phenomena is supported by their selective depletion in highly detrimental neuropsychiatric diseases characterized by a loss of self-conscious emotion and empathy and by a lack of appropriate behavioral response in emotionally-salient situations. The much-needed invasive examination of the VENs in the laboratory has been limited so far by the assumption that this neuron occurs among primates exclusively in humans and great apes. In a recent contribution, we demonstrated the presence of VENs in the agranular anterior insula and ACC in two species of macaque monkeys (rhesus and cynomolgus) typically used in the laboratory. VENs were also found in the same regions in a broad range of monkeys and in lesser apes. In the present contribution, we demonstrate that VENs in the macaque occur in an architectonically distinct area of the agranular anterior insula, namely ´Ia5´, and in several distinct areas in ACC and in the medial wall of the prefrontal cortex. This specific areal distribution of the VENs suggests that their developmental fate is bound to the overall plan of development and parcellation of the cerebral cortex in primates. It also offers a unique opportunity to examine the primal function and connections of the VENs on the basis of what is already known about these areas in the macaque monkey. Such examination could provide significantly new and valuable information on the possible role of the VENs in human self-awareness, social cognition and related neuropsychiatric disorders.}, department = {Department Logothetis}, web_url = {http://fens.ekonnect.co/FENS_331/poster_35097/program.aspx}, event_place = {Barcelona, Spain}, event_name = {8th Forum of European Neuroscience (FENS 2012)}, author = {Evrard, HC and Forro, T and Logothetis, NK} } @Poster { ForroLE2011, title = {Distribution of a large spindle-shaped neuron in the anterior agranular insula in the macaque monkey}, year = {2011}, month = {11}, volume = {41}, number = {817.07}, abstract = {We report the presence of a large spindle-shaped neuron in layer 5b in the anterior agranular insula in the rhesus and cynomolgus macaque monkeys. This neuron shares numerous characteristics with the von Economo neuron (VEN), a large spindle-shaped neuron that is present in layer 5b in the anterior insula in humans and great apes and that appears to have a crucial role in self-awareness and social cognition in humans. Thus, like the VEN, the large spindle-shaped neuron in the macaque has an elongate perikaryon that is symmetrical about its height and width; has a unique basal dendrite that is proximally as thick as its apical dendrite; is larger or as large as the local pyramidal neurons and much larger than the fusiform neuron in layer 6; and expresses the neurofilament protein SMI-32 and the serotonin receptor 2b. Golgi material reveals that its dendrites have all the characteristics of a projecting neuron; and it is retrogradely labeled with neuronal tracer injected at a distant site. It is consistently mingled with fork neurons. Finally, the portion of the insula that contains this spindle-shaped neuron in the macaque is located, like in humans and great apes, in a portion of the agranular insula that is anterior to the limen and medial to the superior sulcus of the insula. We conclude that the large spindle-shaped neuron in the macaque insula is anatomically homologous with the hominoid VEN, and that the anterior agranular insula in the macaque is at least in part anatomically homologous with the human anterior insula (or frontoinsula). Further evidence from this laboratory indicates that the VEN is also present in a similar portion of the anterior agranular insula in other species of monkeys and in lesser apes (Evrard et al., this meeting). The VEN is smaller and much less frequent in the macaque than in human; it is therefore unlikely that its role in the macaque is as evolved as it appears to be in human. Nevertheless, the present demonstration offers a unique opportunity to examine in the laboratory the hodology and primal function of a brain region that appears to be central to human self-awareness and in which malformation, lesion or degeneration have a dramatic impact on human bodily and emotional feelings as well as social interaction.}, department = {Department Logothetis}, web_url = {http://www.sfn.org/am2011/}, event_place = {Washington, DC, USA}, event_name = {41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011)}, author = {Forro, T and Logothetis, NK and Evrard, HC} } @Poster { EvrardZSL2011, title = {Large spindle-shaped neurons in the anterior insula in lesser apes and monkeys}, year = {2011}, month = {11}, volume = {41}, number = {817.15}, abstract = {We report the presence of a large spindle-shaped neuron in layer 5b in the agranular insula in several different species of Old World monkeys and in two species of lesser apes. The Old World monkeys included five rhesus and five cynomolgus macaques, two baboons, two mangabeys, two langurs, one colobus, one blue monkey and one patas monkey. The lesser apes included two gibbons and one siamang. The large spindle-shaped neuron found in all these species shared numerous characteristics with the von Economo neuron (VEN), a large spindle-shaped neuron that is present in layer 5b in the anterior insula in humans and great apes and that appears to have a crucial role in self-awareness and social cognition in humans. Thus, the large spindle-shaped neuron in the monkeys, gibbon and siamang had an elongate perikaryon that was symmetrical about its height and width; had a unique basal dendrite that was proximally as thick as its apical dendrite; was as large or larger than local pyramidal neurons and much larger than the small fusiform neurons in layer 6; was consistently mingled with fork neurons; and was located, as in humans, in a restricted portion of the agranular insula, anterior to the limen and medial to the superior limiting sulcus of the insula. Taken together with evidence from a more detailed analysis in the macaque monkey (Forro et al., this meeting), we conclude that the large-spindle shaped neuron found in the Old World monkeys and lesser apes is anatomically homologous with the hominoid VEN. A preliminary examination of the anterior agranular insula in several species of New World monkeys did not reveal the presence of the large spindle-shaped neuron, except for a few isolated neurons found in one spider monkey. The present findings suggest that the VEN emerged much earlier than previously proposed and was present already at least in a common ancestor of the cercopithecoids and hominoids. Although being much less numerous and smaller than in humans, the VEN in monkeys and lesser apes likely shares some primal functions and connections with the VEN in humans. Future comparative and quantitative analyses of the distribution of the VEN across primate species living in different ecological niches and having different behaviors and social organizations might provide valuable information regarding the evolutive mechanisms that lead to the marked development and crucial role of VEN in humans.}, department = {Department Logothetis}, web_url = {http://www.sfn.org/am2011/}, event_place = {Washington, DC, USA}, event_name = {41st Annual Meeting of the Society for Neuroscience (Neuroscience 2011)}, author = {Evrard, HC and Zilles, K and Sherwood, CC and Logothetis, NK} } @Poster { NevesEEBL2010, title = {Mapping noradrenergic projections from locus coeruleus using classical fluorescent tracer and MRI-visible contrast agent}, year = {2010}, month = {7}, volume = {7}, number = {087.13}, abstract = {We examined anterograde labeling of noradrenergic terminals originating from the neurons of brain stem neuromodulatory nucleus Locus Coeruleus (LC), a major course of noradrenaline in the rat forebrain, by means of simultaneous iontophoretic injection of paramagnetic (Mn2+) and classical (fluorescent dextran) tracers in the LC. In order to detect Mn2+ transport, MRI scanning was performed in each rat before and 24h after injection and, subsequently, MR images were compared using voxel-based t-test (voxel size: 0.25x0.25x0.25mm). Fluorescent dextran monosynaptic anterograde transport was analysed 5 days after injection. Iontophoretic injection of Mn2+ did not produce neurotoxic effects as there were no signs of neuronal death or glial inflammatory reaction at the injection site 5 days after injection. Both methods revealed reliable labeling in major subcortical terminal fields of LC neurons (Swanson and Hartman, 1975; Ungerstedt, 1971) including central nucleus of amygdala, internal capsule, anterior part of bed nucleus of the stria terminalis, and mesencephalic region. Consistent with previous studies, labeling was predominantly ipsilateral to the injection site. Classical tracer readily detected terminals like fibers of passage typical for noradrenergic innervation of cortical regions. In contrast, manganese-enhanced MRI (MEMRI) method failed to visualize such dispersed noradrenergic innervation in the cortex. On the other hand, MEMRI might be more sensitive for detecting patterns of functional connectivity. Consistent and strong Mn-labeling in hippocampus was observed, which was not proportional to anatomical connectivity labeled by dextran. Thus, the tract-tracing using MEMRI preferentially maps the target sites of rather strong and highly concentrated projections, but not dispersed terminal fields. Despite the relatively low resolution of MEMRI technique compared to florescent microscopy, this novel tract-tracing method can be successfully applied for visualization of major neural pathways and their reorganization in the same animal in longitudinal studies including those concentrating on development, aging, plasticity, or disease-related neurodegeneration.}, department = {Department Logothetis}, web_url = {http://fens2010.neurosciences.asso.fr/}, event_place = {Amsterdam, Netherlands}, event_name = {7th Forum of European Neuroscience (FENS 2010)}, author = {Neves, RM and Eschenko, O and Evrard, H and Beyerlein, M and Logothetis, NK} } @Poster { NevesEEBL2009, title = {Anterograde analysis of noradrenergic projections in the rat forebrain using classical and manganese-enhanced MRI (MEMRI) tract-tracing}, year = {2009}, month = {11}, volume = {10}, number = {10}, pages = {29}, abstract = {We examined anterograde labeling of noradrenergic terminals originating from the neurons of brain stem neuromodulatory nucleus Locus Coeruleus (LC), a major course of noradrenaline in the rat forebrain, by means of simultaneous iontophoretic injection of paramagnetic (Mn2 +) and classical (fluorescent dextran) tracers in the LC. Both MEMRI and fluorescent microscopy revealed anterograde labeling in major terminal fields of LC neurons (Swanson and Hartman, 1975; Ungerstedt, 1971) 24 h and 5 d after injection, respectively. Predominantly ipsilateral labeling of thalamic nuclei, primary sensory cortices, medial prefrontal cortex, and olfactory bulbs reflected previously demonstrated monosynaptic projections of the LC neurons in multiple target brain regions. The labeling patterns of both paramagnetic and classical tracers were strikingly similar. Importantly, iontophoretic injection of Mn2+ did not produce neurotoxic effects as there were no signs of neuronal death or glial inflammatory reaction at the injection site 5 days after injection. The reported results further validate MEMRI tract-tracing technique allowing visualization a highly distributed and distal efferent projections arising from the brain stem nucleus. Thus, MEMRI may be used for mapping convergent target brain regions of different neuromodulatory systems in the same animal and their functional reorganization in longitudinal studies.}, department = {Department Logothetis}, web_url = {http://www.neuroschool-tuebingen-nena.de/}, event_place = {Ellwangen, Germany}, event_name = {10th Conference of Junior Neuroscientists of T{\"u}bingen (NeNa 2009)}, author = {Neves, RM and Eschenko, O and Evrard, H and Beyerlein, M and Logothetis, NK} } @Poster { 6113, title = {Graded cooling of the skin activates the insular cortex in the anesthetized macaque monkey}, year = {2009}, month = {10}, volume = {39}, number = {854.8}, abstract = {Neuroanatomical and functional evidence indicates that pain and temperature are represented with numerous other interoceptive sensory inputs in a phylogenetically novel spinothalamocortical pathway in primates (for review, see Craig, TINS 2003 26:303-307). Prior tract-tracing studies in the monkey demonstrated that nociceptive and thermoreceptive spinothalamic tract neurons in spinal lamina I primarily project to the posterior part of the ventromedial nucleus of the thalamus (VMpo; a nucleus specific to primates) and that nociceptive and thermoreceptive thalamocortical tract neurons in VMpo project to the dorsal posterior insular cortex. Electrophysiological recordings in spinal lamina I and VMpo in the anesthetized monkey revealed precise encoding of the grading of thermal and pain stimuli. Functional imaging in humans and EEG in monkeys indicated that the dorsal posterior insula is strongly activated by graded cooling of the skin. In the present study, we examined the activation of the insular cortex using high-resolution functional magnetic resonance imaging (4.7T) with thermal stimulation of the skin in two anesthetized cynomolgus monkeys. A graded cooling of the palmar surface of the foot from a baseline temperature of 35\(^{\circ}\)C to a target temperature of 15\(^{\circ}\)C (0.5\(^{\circ}\)C/sec) followed by a re-warming to baseline (0.5\(^{\circ}\)C/sec) produced highly significant (p < 0.001) BOLD signal exclusively in the dorsal mid-posterior portion of the contralateral insular cortex. No or poorly significant (p < 0.05) BOLD signal occurred in primary and secondary somatosensory cortices. These results support prior evidence that the insula in primates encodes ongoing interoceptive activity necessary to maintain homeostatic balance (e.g. thermoregulation). Neuroanatomical tract-tracers were injected in the insular regions displaying significant BOLD signal; mapping of anterograde and retrograde labeling from these injections will be presented.}, department = {Department Logothetis}, web_url = {http://www.abstractsonline.com/Plan/ViewAbstract.aspx?sKey=900967bd-51c4-4851-bf1c-9ac4ab8672ed\&cKey=50872dae-3636-42e4-a7d3-d49edcf1e79e}, institute = {Biologische Kybernetik}, organization = {Max-Planck-Gesellschaft}, event_place = {Chicago, IL, USA}, event_name = {39th Annual Meeting of the Society for Neuroscience (Neuroscience 2009)}, language = {en}, author = {Evrard, HC and Augath, M and Baumg{\"a}rtner, U and Craig, AD and Treede, RD and Logothetis, NK} } @Poster { EvrardC2008_2, title = {Retrograde analysis of cerebellar inputs to ventrolateral, intralaminar and midline thalamic nuclei in macaque monkeys}, year = {2008}, month = {2}, event_place = {T{\"u}bingen, Germany}, event_name = {1st Annual Meeting of Primate Neurobiology}, author = {Evrard, HC and Craig, AD} } @Poster { EvrardC2007, title = {Retrograde analysis of cerebellar inputs to ventrolateral, intralaminar and midline thalamic nuclei in macaque monkeys}, year = {2007}, month = {11}, volume = {37}, number = {512.18}, abstract = {We injected retrograde tracers (cholera toxin b and fluorescent dextrans) in distinct thalamic nuclei to examine the origin of their cerebellar inputs. In a previous study (Evrard \& Craig, SfN 2006), we showed that the posterior ventral part of the ventral lateral nucleus (VLpv) receives topographically organized cerebellar inputs from the anterior two thirds of the dentate nucleus (DN), the entire anterior interposed nucleus (NIA) and the dorsal portion of the posterior interposed nucleus (NIP). In the present study, injections were made in the posterior dorsal part of the ventral lateral nucleus (VLpd), area X (X), the central lateral nucleus (CL), the centre median/parafascicular complex (CM/Pf) and the medial dorsal nucleus (MD). Injections in VLpd, X and CL produced abundant labeling in DN, NIA and NIP. The cerebellar labeling from these thalamic nuclei clearly overlapped with the labeling obtained after injection in VLpv but also included the caudal third of DN and the ventral portion of NIP. Injections in Pf labeled relatively few cells that were widely scattered in DN, especially its caudal half. By contrast, injections in CM produced abundant labeling in all parts of DN, NIA and NIP. Injections in MD labeled neurons specifically confined to the ventral posterior portion of DN and to the ventral portion of NIP. These two regions always remained unlabeled after large injections in VLpv and are thus clearly distinct portions of the deep cerebellar nuclei. The ventral posterior portion of DN might correspond to the “non-motor” portion of DN labeled after injections of transneuronal retrograde tracer in prefrontal cortex (Middleton \& Strick, J Neurosci 2001 15: 700-12). Overall, these results show that cerebellar inputs to different thalamic nuclei originate from overlapping regions of the deep cerebellar nuclei. Whether these overlapping regions contain neurons that send collateral projections to several thalamic nuclei or intermingled neurons that project to only one thalamic nucleus remains to be tested.}, web_url = {http://www.sfn.org/am2007/}, event_place = {San Diego, CA, USA}, event_name = {37th Annual Meeting of the Society for Neuroscience (Neuroscience 2007)}, author = {Evrard, HC and Craig, AD} } @Poster { EvrardC2006, title = {Retrograde analysis of topography in monkey cerebellothalamic projections}, year = {2006}, month = {10}, volume = {36}, number = {740.11}, abstract = {Cerebellothalamic neurons were investigated using retrograde labeling from single or multiple injections of cholera toxin b and fluorescent dextrans (green, purple, red) in the posteroventral part of the ventral lateral thalamic nucleus (VLpv; Olszweski’s VPLo), the main source of thalamic input to primary motor cortex. Iontophoretic or pressure injections were guided by microelectrode recordings in anesthetized cynomolgus monkeys. Large injections filling VLpv (and adjacent nuclei) produced abundant retrograde labeling in all of the contralateral deep cerebellar nuclei. Small injections at VLpv sites responsive to “tap” of contralateral hindlimb, forelimb, or face labeled groups of neurons in the anterior two-thirds of the dentate nucleus and in the anterior and posterior interposed nuclei with a general anteroposterior topography (with subcomponents) in each nucleus: hindlimb anterior and ventral, face posterior and dorsal, and forelimb in between hindlimb and face. Simultaneous injections of multiple tracers in VLpv (one tracer per body region with no overlap between injections) confirmed the general anteroposterior somatotopography but also revealed considerable intermingling between cells labeled with different tracers. Interestingly, only 3\% of cells were double labeled. This organization contrasts with the concept of a segregated pathway linking separate portions of the deep cerebellar nuclei with separate portions of thalamus and cortex. Rather, these observations resemble the pattern of complex topography that has been observed physiologically in the primary motor cortex. These data are consistent with the idea that muscle synergies are represented already in the anatomical organization of cerebellothalamic projections by a general topographic framework in which regions of intermingling provide the basis for movement coordination of different parts of the body.}, web_url = {http://www.sfn.org/index.aspx?pagename=abstracts_ampublications}, event_place = {Atlanta, GA, USA}, event_name = {36th Annual Meeting of the Society for Neuroscience (Neuroscience 2006)}, author = {Evrard, HC and Craig, AD} } @Poster { EvrardE2005, title = {Rapid effects of spinal estrogen synthesis on nociception behavior in adult male rats}, year = {2005}, month = {11}, volume = {35}, web_url = {http://www.sfn.org/index.aspx?pagename=abstracts_ampublications}, event_place = {Washington, DC, USA}, event_name = {35th Annual Meeting of the Society for Neuroscience (Neuroscience 2005)}, author = {Evrard, HC and Erskine, MS} } @Poster { EvrardHBE2004, title = {Distribution and function of aromatase along the spinal cord and hindbrain pain pathway}, year = {2004}, month = {10}, volume = {34}, number = {291.11}, abstract = {The estrogenic regulation of nociception can occur in multiple central areas including the dorsal horn of the spinal cord and various nuclei of the hindbrain that express estrogen receptors and where specific reactions to nociceptive stimuli have been observed. In Japanese quail, the estrogen-synthesizing enzyme, aromatase, is expressed in numerous neurons throughout the rostrocaudal extent of the spinal dorsal horn and in sensory and integrating nuclei in the hindbrain. We thus initiated a research program to assess the presence and function of aromatase in spinal and hindbrain areas involved in nociception in mammals. Numerous aromatase-immunoreactive fibers bearing varicosities were previously observed in the rat spinal cord. We demonstrate here the presence in the rat brainstem of aromatase immunoreactivity in sensory (trigeminal, solitary tract) and integrating (parabrachial, raphe) nuclei that are homologous to those expressing aromatase in quail. Despite this overall similarity, a striking difference was found at the cellular level: both perikarya and fibers were labeled in quail while only fibers were immunoreactive in rats. Recent behavioral studies in quail indicate that spinal aromatase produces estrogens that decrease the foot withdrawal latency to a painful thermal stimulus within 1 minute. Similarly, an intrathecal injection of 17\(\beta\)-estradiol (100 nM) in gonadally-intact male rats reduces the foot withdrawal latency to a painful thermal stimulus within 5 minutes. Together, these data strongly suggest the existence of a well-conserved rapid regulation of nociception that depends on the local synthesis of estrogens. Whether the rapid effect of endogenous estrogens on nociception in rat relies, like in quail, on spinal aromatization is currently under investigation.}, web_url = {http://www.sfn.org/absarchive/}, event_place = {San Diego, CA, USA}, event_name = {34th Annual Meeting of the Society for Neuroscience (Neuroscience 2004)}, author = {Evrard, HC and Harada, N and Balthazart, J and Erskine, MS} } @Poster { EvrardHB2004_2, title = {Effects of aromatization of androgens into estrogens in the spinal cord}, year = {2004}, month = {5}, volume = {2}, event_place = {Vancouver, Canada}, event_name = {2nd Joint Scientific Meeting of the American Pain Society and the Canadian Pain Society}, author = {Evrard, HC and Harada, N and Balthazart, J} } @Poster { EvrardHB2003, title = {Localization of aromatase-immunoreactive neurons in sensory and integrating nuclei of the hindbrain in Japanese quail (Coturnix japonica)}, year = {2003}, month = {11}, volume = {33}, number = {596.10}, abstract = {The distribution of the estrogen synthesizing enzyme (aromatase) in the hindbrain (rhombencephalon and mesencephalon) of male adult quail was investigated by immunocytochemistry. Aromatase-immunoreactive neuronal structures (perikarya and fibers bearing punctate structures) were observed in sensory (trigeminal, solitary tract, part of the vestibular, optic tectum) and integrating (parabrachial, periaqueductal, cerulean, raphe) nuclei. Besides the expression of aromatase in these well delineated nuclei, dense to scattered networks of immunoreactive fibers were found quasi-ubiquitously in the hindbrain and, in particular, in its rostral and dorsal parts. To a lesser extent, they were also present throughout the premotor nuclei of the reticular formation and in various fiber tracts. In contrast, no immunoreactive signal was found in motor regions and in most of the statoaccoustic (cerebellum, vestibular, cochlear, olive, pontine) nuclei. The expression of aromatase in perikarya and fibers in areas of the adult hindbrain where estrogen receptors have been previously identified suggests a role for locally produced estrogens in the control of sensory and coordinating functions contrary to the widespread assumption that these functions are controlled by steroids produced by the gonads. We had previously demonstrated the presence of aromatase in neurons of the dorsal (sensory) horn of the spinal cord in quail. The present work shows that aromatase-immunoreactive structures are in fact broadly distributed in sensory nuclei in the caudal part of the quail brain and allows to extend the concept of spinal sensory aromatase to the broader concept of sensory aromatase according to which estrogens produced in sensory nuclei of the hindbrain could control a diversity of sensory processes.}, web_url = {http://www.sfn.org/index.aspx?pagename=annualmeeting_futureandpast}, event_place = {New Orleans, LA, USA}, event_name = {33rd Annual Meeting of the Society for Neuroscience (Neuroscience 2003)}, author = {Evrard, HC and Harada, N and Balthazart, J} } @Poster { EvrardB2003_2, title = {Spinal estrogen synthesis rapidly increases responsiveness to noxious stimuli}, year = {2003}, month = {9}, volume = {4}, event_place = {Praha, Czech Republic}, event_name = {4th Congress of the European Federation of IASP Chapters: Pain in Europe IV (EFIC 2003)}, author = {Evrard, HC and Balthazart, J} } @Poster { EvrardB2002_3, title = {Effects of estrogens on spinal motor and sensory processes in Japanese quail}, year = {2002}, month = {11}, volume = {32}, event_place = {Orlando, FL, USA}, event_name = {32nd Annual Meeting of the Society for Neuroscience (Neuroscience 2002)}, author = {Evrard, HC and Balthazart, J} } @Poster { EvrardHB2001, title = {Localization of estrogen-synthase (aromatase) in the rat spinal cord}, year = {2001}, month = {11}, volume = {31}, event_place = {San Diego, CA, USA}, event_name = {31st Annual Meeting of the Society for Neuroscience (Neuroscience 2001)}, author = {Evrard, HC and Harada, N and Balthazart, J} } @Poster { EvrardWB2000, title = {Neurochemical environment of the quail spinal estrogen-synthase (aromatase) neurons}, year = {2000}, month = {11}, volume = {30}, event_place = {New Orleans, LA, USA}, event_name = {30th Annual Meeting of the Society for Neuroscience (Neuroscience 2000)}, author = {Evrard, HC and Willems, E and Balthazart, J} } @Poster { EvrardB2000, title = {Localization of estrogen receptor, aromatase, and nociception-related compounds in the quail spinal dorsal horns}, year = {2000}, month = {9}, volume = {5}, event_place = {Leuven, Belgium}, event_name = {5th EURON Ph.D. Students Day}, author = {Evrard, HC and Balthazart, J} } @Poster { EvrardB2000_2, title = {Localization of estrogen-synthase and estrogen receptor immunoreactive cells in the brainstem of the Japanese quail}, year = {2000}, month = {9}, volume = {4}, event_place = {Maastricht, The Netherlands}, event_name = {4th EURON Ph.D. Students Day}, author = {Evrard, HC and Balthazart, J} } @Poster { EvrardB2000_3, title = {Localization of estrogen-synthase and estrogen receptor immunoreactive cells in the descending nucleus of the trigeminal nerve of the Japanese quail}, year = {2000}, month = {6}, event_place = {Brighton, UK}, event_name = {Federation of European Neuroscience Societies Millennium Meeting (FENS 2000)}, author = {Evrard, HC and Balthazart, J} } @Poster { EvrardBFAHB1999, title = {Localization and control of aromatase in the dorsal horns of the quail spinal cord}, year = {1999}, month = {10}, volume = {29}, event_place = {Miami Beach, FL, USA}, event_name = {29th Annual Meeting of the Society for Neuroscience (Neuroscience 1999)}, author = {Evrard, HC and Baillien, M and Foidart, A and Absil, P and Harada, N and Balthazart, J} } @Poster { EvrardB1999, title = {On a way to investigate the possible involvement of spinal aromatase in sensory perception}, year = {1999}, month = {6}, volume = {19}, event_place = {Nijmegen, The Netherlands}, event_name = {19th Low Countries Meeting}, author = {Evrard, HC and Balthazart, J} }