LONG-LASTING CHANGES OF NEURONAL-ACTIVITY IN THE MOTOR CORTEX OF CATS

THE effect Of tetanic intracortical microstimulation (ICMS) of superfi cial layers of the motor cortex on unit discharges responding to stimu lation of the peripheral receptive fields was examined in the motor co rtex (area 4y). Single or multiple unit discharges were isolated from 15 recording sites near the stimulating electrodes. Following tetanic ICMS, the response to the same peripheral stimulation showed a long la sting increase at six recording sites, a long lasting decrease at two sites and transient increase or decrease at four sites. In the rest of the sites, tetanic ICMS had no effect. The results demonstrate the ex istence of use-dependent modification of information processing in the motor cortex and support the hypothesis that the motor cortex partici pates in learning motor skills.