Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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TUTORIAL BCCN/BFNT AG-Seminar

Tuesday, 01.04.2014 16 c.t.

Determinants of spontaneous bursts in cultured networks of central neurons

by Prof. Dr. Menahem Segal
from Weizmann Institute of Sience, Dept. Neurobiology, Rehovot, Israel

Contact person: Ahmed El Hady

Location

MPI für experimentelle Medizin

Abstract

Spontaneous synchronized activity of neuronal assemblies is an essential attribute of brain function. Yet, the cellular mechanisms that determine the triggering and maintenance of network bursts are not fully understood. The importance of spontaneous network activity for the maintenance of cultured neurons is exemplified by the fact that its chronic blockade leads to death of these neurons. To investigate neuronal network bursts, small scale networks consisting of 2-30 hippocampal neurons were created on permissive islands. Some networks displayed spontaneous bursts encompassing the entire neuronal population. The bursts did not depend on the presence of inhibitory neurons or on network size. A leader neuron was occasionally identified as the one neuron that started to fire before all other members of the network and that its activation leads to a network burst. Surprisingly, these network bursts were still present following the elimination of ‘leader' neurons, indicating that they are not indispensable even for small scale networks. The duration of network bursts was apparently dependent on the depletion of presynaptic resources and not on changes in postsynaptic properties. Finally, miniature synaptic currents were generated in synapses on dendritic shaft and not on dendritic spines, and were larger than those found in large dispersed cultures. Occasional presence of GABAergic neurons in the small network modified the connectivity of the network in a distinct manner. Thus, the microculture provides a convenient test system for studying the generation of network activity in the brain.

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