Long-term changes, induced by microstimulation of the neocortex, in the efficiency of excitatory postsynaptic transmission in the thalamocortical networks.

Neuronal networks with synaptic plasticity, consisting of cells located in various loci of the AC and the MGB, were investigated. It was demonstrated that, as a result of MS applied in the region of cortical elements of the network, connections could alter between all elements of the cortex-thalamus-cortex neuronal network. Changes were manifested in the form of LTP and/or LTD of the efficiency of excitatory connections, as well as in the form of intensification or attenuation of the action of the "common source'; the changes were maintained for tens of minutes. The number of connections between stimulated and non-stimulated elements of the network increased. Neurons in which more favorable conditions for LTP developed were distinguished in the networks. The character of the modification of synapses formed by the axons of several cells on one of the elements of the network could vary. Synapses formed by axonal collaterals of one cell on several elements of the network could also be modified variously.