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Dr. Nikolaos Aggelopoulos

Address: Spemannstr. 38
72076 Tübingen
Room number: 252

 

Picture of Aggelopoulos, Nikolaos, Dr.

Nikolaos Aggelopoulos

Position: Postdoctoral Fellow  Unit: Alumni Logothetis

Cholinergic effects on cognition in the primate brain

Introduction and Scientific Aims

Acetylcholine is a neuronal transmitter and neuromodulator that has documented effects on attentional tasks [1, 2] via muscarinic receptors [3]. Muscarinic receptors are also believed to have a role in cortical plasticity [4]. The aim of this project is to demonstrate the effects of the muscarinic antagonist scopolamine in a categorization task involving attention and learning.

Methods

Two monkeys have been fully trained using operant conditioning in a categorization task to use levers to indicate which category a stimulus belongs to. Muscarinic mechanisms were antagonised by systemic administration of scopolamine. Neurons of the basal cholinergic forebrain nuclei were identified prior to their stimulation in order to test the role of cholinergic mechanisms in cortical plasticity during this task.

Results and preliminary conclusions

The categorization of novel stimuli, that is the ability to assign a new stimulus to a category, was impaired by a muscarinic receptor block (Aggelopoulos et al, 2011). Neuronal recordings from the basal cholinergic forebrain have revealed neurons with a capacity to respond to a great range of visual stimuli, including also non-coherent images, that were paired with a reward.

Supervised students and collaborators

Alexander Rauch, collaborator; Ceren Batal, Master student on a lab rotation


Fig.1. Novel stimuli were presented varying in coherence (examples on the left panel). The categorization of novel stimuli was impaired by a muscarinic receptor block by scopolamine (cyan curve, right).

References

1. Sarter, M., Bruno, J.P. Neuroscience 95, 933-952 (2000) .

2. Furey, M.L. et al Neuropsychopharmacology 33, 913-923 (2008).

3. Herrero, J.L., et al Nature 454, 1110-1114 (2008)

4. Miasnikov AA, McLin D 3rd, Weinberger NM. Neuroreport. 12, 1537-42 (2001).

5. Aggelopoulos NC, Liebe S, Logothetis NK & Rainer G: Frontiers in Behavioral Neuroscience 5(73):1-10 (2011)

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Articles (19):

Aggelopoulos NC, Liebe S, Logothetis NK and Rainer G (November-2011) Cholinergic control of visual categorization in macaques Frontiers in Behavioral Neuroscience 5(73) 1-10.
Aggelopoulos NC, Chakrabarty S and Edgley SA (May-2008) Presynaptic control of transmission through group II muscle afferents in the midlumbar and sacral segments of the spinal cord is independent of corticospinal control Experimental Brain Research 187(1) 61-70.
Franco L, Rolls ET, Aggelopoulos N and Jerez JM (June-2007) Neuronal selectivity, population sparseness, and ergodicity in the inferior temporal visual cortex Biological Cybernetics 96(6) 547.
Rolls ET, Franco L, Aggelopoulos NC and Jerez JM (November-2006) Information in the first spike, the order of spikes, and the number of spikes provided by neurons in the inferior temporal visual cortex Vision Research 46(25) 4193-4205.
Aggelopoulos NC and Edgley SA (June-2006) Short latency crossed inhibitory reflex actions evoked from cutaneous afferents Experimental Brain Research 171(4) 541-550.
Aggelopoulos NC and Rolls ET (December-2005) Scene perception: inferior temporal cortex neurons encode the positions of different objects in the scene European Journal of Neuroscience 22(11) 2903-2916.
Aggelopoulos NC, Franco L and Rolls ET (March-2005) Object perception in natural scenes: encoding by inferior temporal cortex simultaneously recorded neurons Journal of Neurophysiology 93(3) 1342-1357.
Franco L, Rolls ET, Aggelopoulos NC and Treves A (April-2004) The use of decoding to analyze the contribution to the information of the correlations between the firing of simultaneously recorded neurons Experimental Brain Research 155(3) 370-384.
Rolls ET, Aggelopoulos NC, Franco L and Treves A (January-2004) Information encoding in the inferior temporal visual cortex: contributions of the firing rates and the correlations between the firing of neurons Biological Cybernetics 90(1) 19-32.
Franco L, Aggelopoulos NC and Reece S (May-2003) An information theoretic approach to the contributions of the firing rates and the correlations between the firing of neurons Journal of Neurophysiology 89(5) 2810-2822.
Rolls ET, Aggelopoulos NC and Zheng F (January-2003) The receptive fields of inferior temporal cortex neurons in natural scenes Journal of Neuroscience 23(1) 339-348.
Aggelopoulos NC and Meissl H (February-2000) Responses of neurones of the rat suprachiasmatic nucleus to retinal illumination under photopic and scotopic conditions Journal of Physiology 523(1) 211-222.
Aggelopoulos NC, Brown SJ, Demaine C, Harris NG and Jones HC (October-1997) An abnormal distribution of melatonin receptors in the newborn rat with inherited prenatal hydrocephalus Neuroscience 80(3) 669-673.
Aggelopoulos NC, Chakrabarty S and Edgley SA (February-1997) Evoked excitability changes at the terminals of midlumbar premotor interneurons in the cat spinal cord Journal of Neuroscience 17(4) 1512-1518.
Aggelopoulos NC, Bawa P and Edgley SA (December-1996) Activation of midlumbar neurones by afferents from anterior hindlimb muscles in the cat Journal of Physiology 497(3) 795-802.
Aggelopoulos NC, Burton MJ, Clarke RW and Edgley SA (January-1996) Characterization of a descending system that enables crossed group II inhibitory reflex pathways in the cat spinal cord Journal of Neuroscience 16(2) 723-729.
Aggelopoulos NC, Duke C and Edgley SA (August-1995) Non-uniform conduction time in the olivocerebellar pathway in the anaesthetized cat Journal of Physiology 486(3) 763-768.
Aggelopoulos NC and Edgley SA (February-1995) Segmental localisation of the relays mediating crossed inhibition of hindlimb motoneurones from group II afferents in the anaesthetized cat spinal cord Neuroscience Letters 185(1) 60-64.
Aggelopoulos NC, Parnavelas JG and Edmunds S (August-1989) Synaptogenesis in the dorsal lateral geniculate nucleus of the rat Anatomy and Embryology 180(3) 243-257.

Posters (5):

Azevedo FAC, Aggelopoulos NC, Logothetis NK and Rainer G (July-2012): Responses Of Neurons In The Nucleus Basalis To Visual Stimuli Differing In Their Familiarity, Category And Coherence, 8th Forum of European Neuroscience (FENS 2012), Barcelona, Spain.
Aggelopoulos NC, Melano T, Logothetis NK and Rainer G (June-2010): Cholinergic Dependence of a Cognitive Task, AREADNE 2010: Research in Encoding And Decoding of Neural Ensembles, Santorini, Greece.
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Aggelopoulos NC, Liebe S, Logothetis NK and Rainer G (September-2009): The effects of scopolamine on visual categorization in macaques, 23rd Meeting of the Hellenic Society for Neuroscience (HSfN 2009), Rhodos, Greece.
pdf
Aggelopoulos NC, Franco L, Jerez JM and Rolls ET (June-2008): The sparseness of stimulus encoding by single neurons and by populations of neurons in the inferior temporal cortex, AREADNE 2008: Research in Encoding and Decoding of Neural Ensembles, Santorini, Greece.
pdf
Aggelopoulos NC and Rolls ET (July-2004): Rapid invariant view learning of novel objects in the inferior temporal cortex (IT) of macaques, 4th Forum of European Neuroscience (FENS 2004), Lisboa, Portugal.
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Talks (6):

Aggelopoulos N (June-27-2011) Invited Lecture: The representation of objects in the inferior temporal cortex of the macaque monkey, Life and Brain Center, University of Bonn Medical Center, Bonn, Germany.
Aggelopoulos N (December-9-2010) Invited Lecture: The representation of objects in the inferior temporal cortex of the macaque monkey, Max Planck Institute for Brain Research, Frankfurt a. M., Germany.
Aggelopoulos N (December-2-2010) Invited Lecture: Commercially available spike sorting software, Workshop "Tetrode recording and spike sorting", Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
Aggelopoulos NC, Liebe S, Logothetis NK and Rainer G (August-2009) Abstract Talk: Dependence of a visual categorisation task on acetylcholine, 32nd European Conference of Visual Perception, Regensburg, Germany, Perception, 38(ECVP Abstract Supplement) 108.
Aggelopoulos N (May-14-2009) Invited Lecture: From sensation to perception, Department of Physiology - University of Ioannina, Ioannina, Greece.
Aggelopoulos NC, Liebe S, Logothetis NK and Rainer G (May-2009) Abstract Talk: Dependence of a cognitive task on acetylcholine, Data Mining in Biomedicine Conference at the Athens Institute of Technology (DMINBIO-09), Athens, Greece.
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Last updated: Monday, 22.05.2017