Long-lasting changes of neuronal activity in the motor cortex of cats.

The effect of tetanic intracortical microstimulation (ICMS) of superficial layers of the motor cortex on unit discharges responding to stimulation of the peripheral receptive fields was examined in the motor cortex (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 lasting 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 existence of use-dependent modification of information processing in the motor cortex and support the hypothesis that the motor cortex participates in learning motor skills.