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Genaue Beschreibung der Veranstaltung:
Referent/in:Prof. Dr. med. Andreas Draguhn, Institut für Physiologie und Pathophysiologie, Universität Heidelberg
Thema:Oscillating hippocampal networks - patterns, mechanisms and potential 'meaning' of cooperative neuronal activity
Beschreibung:Bernstein Seminar
Ausführliche Beschreibung:In almost all brain areas, neurons co-ordinate their activity in time, sometimes firing action potentials in strict synchrony, sometimes firing in sequences or in other temporal patterns. Of similar importance is the selection of active neurons: In any given situation, only a sub-set of local neurons is active while the remaining cells (usually the majority) stay silent. As a result, networks express defined spatiotemporal patterns of activity. Very often, the timing of neuronal activity is determined by underlying network oscillations which define a temporal framework for action potentials.
During past years, we have analyzed one important pattern of oscillations which contributes to memory formation in the rodent hippocampus: Sharp wave-ripple complexes. Here, activity of neurons is entrained by a synchronous network oscillation at ~200 Hz.
In the main section of the seminar, we will ask how single neurons are coupled to this fast rhythm and how others are silenced. Combining electrophysiological measurements, computer modelling and morphological analysis we found that the structure and function of axons plays a major role for the selective and temporally precise activation of pyramidal cells. Specifically, we found evidence for two mechanisms: i) electrical coupling between axons; ii) distal origin of axons which emanate from a basal dendrite, rather than from a soma. The first mechanism can, in principle, explain extremely fast signal transition between cells and percolation of high-frequency oscillations through neuronal networks. The second mechanism may explain how dendritic integration of synaptic inputs interacts with the fast, partially autonomous activity of axons. We then will briefly address important features of network oscillations at larger scales: Characteristics and plasticity of multi-neuronal spatiotemporal patterns in hippocampal networks, and large-scale oscillations which recruit major parts of the brain into coherent activity patterns.
Together, we aim at describing and understanding the generation of complex spatiotemporal activity patterns which, in turn, may be the network-level correlate of cognition and behavior.
Veranstaltende Institution:Bernstein Center Freiburg

Bernstein Center Freiburg

Hansastr. 9a
79104 Freiburg

Telefon: 0761 203 9556
Fax: 0761 203 9559
Weitere Infos:
Ansprechpartner/in:Prof. Dr. Ulrich Egert
Tel: 07612039556
Zeit:16.01.2018 17:15
Ort:Bernstein Center, 79104 Freiburg, Hansastr. 9a, Lecture Hall
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