UNIVERSITY OF HERTFORDSHIRE
	     COMPUTER SCIENCE RESEARCH COLLOQUIUM

			    presents


     "Active Dendrites Enable Strong but Sparse Inputs to
	      Determine Orientation selectivity"


			  Dr. Arnd Roth

	(Royal Society Institute for Biomedical Research,
		   University College London)

		    21 February 2018 (Wednesday)

			   1 - 2 pm


		  Hatfield, College Lane Campus
			Seminar Room C408

		  Everyone is Welcome to Attend

		  Refreshments will be available


Abstract:


The dendrites of neocortical pyramidal neurons are excitable. However,
it is unknown how synaptic inputs engage nonlinear dendritic mechanisms
during sensory processing in vivo, and how they in turn influence
action potential output. Here we provide a quantitative account of
the relationship between synaptic inputs, nonlinear dendritic events
and action potential output. We developed a detailed pyramidal neuron
model constrained by in vivo dendritic recordings. We drive this model
with realistic input patterns constrained by sensory responses measured
in vivo and connectivity measured in vitro. Remarkably, we find that
under realistic conditions, dendritic Na+ and NMDA spikes are the major
determinants of neuronal output in vivo. We demonstrate that these
dendritic spikes can be triggered by a surprisingly small number of
strong synaptic inputs, in some cases even by single synapses. We predict
that dendritic excitability allows the 1% strongest synaptic inputs of a
neuron to control the tuning of its output. Active dendrites therefore
allow smaller subcircuits consisting of only a few strongly connected
neurons to achieve selectivity for specific sensory features.


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Hertfordshire Computer Science Research Colloquium
http://cs-colloq.cs.herts.ac.uk