EFFECTS OF LOCAL CONNECTIVITY ON STRIATAL FUNCTION - SIMULATION AND ANALYSIS OF A MODEL

Neuronal population activity was investigated by computer simulation o f a network model based on the neostriatum. Three network topologies w ere studied, based on different assumptions about the synaptic connect ivity among medium spiny neurons. In all networks neurons were interco nnected by inhibitory synapses. The connectivity was either symmetric, in which case all connections between cells were reciprocal and equal in strength; or asymmetric. Simulations showed that networks with sym metric connectivity receiving randomly distributed afferent excitation produced stationary spatial activity patterns. In contrast, asymmetri c connectivity in homogeneous networks produced slow travelling-wave a ctivity across the network. We suggest that the shape of the medium sp iny neurons is an important determinant of synaptic connectivity and t hat changes in the shape of these neurons caused by Huntington's disea se would result in asymmetric connectivity. Slow travelling-wave activ ity produced by asymmetric connectivity in the neostriatum could expla in some aspects of the choreic movement and some electromyographic fea tures seen in Huntington's patients. (C) 1995 Wiley-Liss, Inc.