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Gatsby Computational Neuroscience Unit
Alexandra House, 17 Queen Square, LONDON, WC1N 3AR, UK
Tel: +44 (0) 20 7679 1176, Fax +44 (0) 20 7679 1173, admin@gatsby.ucl.ac.uk, www.gatsby.ucl.ac.uk

 

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WORKSHOP ON:
CENTRAL PROBLEMS IN SINGLE CELL COMPUTATION

16-18 September 2002
By invitation only

Venue
B10 Seminar Room, Alexandra House, 17 Queen Square, London, WC1N 3AR

Dendritic impact on synaptic efficacy and on homeosthasis plasticity
Idan Segev, Institute of Life Sciences, Department of Neurobiology and Interdisciplinary Center for Neural Computation
The dendritic location of the excitatory synapse have functional implications for both the somato-centric (input-output) and the dendro-centric (plastic) view points. At the soma, due to the filtering effect of the dendritic cable, the dendritic location of the synapse is manifested in changes in EPSP time course and amplitude. For passive dendrites, distal synapses are attenuated and have slower rise-time and broader time-course then do proximal synapses. Therefore, distal synapses have different effect on the axonal spike output than do identical proximal synapses. Locally, at the dendritic site, the properties of the dendrites (e.g., input impedance, membrane nonlinearities and the backpropagating action potential) dictate the shape and amplitude of the local EPSP and, thus, its influence on adjacent synapses. Theoretical consequences of synaptic location on the input-output as well on plastic homeosthasis (synaptic scaling), using compartmental modeling and information theory will be presented. The effect of ion channel stochasticity on the temporal accuracy and reliability of the action potential in the axon will also be discussed.