1999 Scientific Retreat
Frances Chance

A Model of Direction Selective Visual Responses
Based on Synaptic Depression

Neurons in the primary visual cortex can demonstrate direction-selectivity, exhibiting strong responses to images moving in one direction and weak responses to images moving in the opposite direction. Recently, experimental work on brain slices led to a descriptive model of synaptic depression, a form of synaptic plasticity in which the strength of a synapse becomes progressively weaker with repeated stimulation. We examine the effect of synaptic depression on neuronal responses by introducing this descriptive model of synaptic depression into a model of a basic primary visual cortical circuit. Direction- selectivity can arise in the model if two distinct sets of inputs, with receptive fields that are spatially shifted from each other, arrive separately through depressing and non-depressing synapses. The model can account for data on direction-selective cells over a wide range of conditions.

 

Speaker Schedule for Current Year  |  Reports from Previous Years
Top of Page | Life Sciences | Brandeis University