Development of directionally selective microcircuits in striate cortex

Abstract

Our point of departure is the canonical microcircuit developed by Douglas and Martin (1991) [DM91]. To demonstrate the explanatory power of the microcircuit, DM91 took the example of the direction-selective neurons that receive monosynaptic input from non-directional thalamic neurons. In this paper we have also modeled directional selectivity but we have gone beyond DM91 by also modeling self-organization mechanisms specific to the development of local circuits giving rise to directional selectivity. Specifically we have introduced traveling waves as the input arriving to the cortex from the thalamus, a layer of cortical minicolumns composed of integrate and fire units and the plasticity mechanisms recently described by Sakmann and colleagues on the effect of spike timing on induction of LTP and LTD in neocortical pyramidal neurons (Markram et al., 1997).