THE INFLUENCE OF 2-AMINO-5-PHOSPHONOPENTA NOIC ACID (AP5), A GLUTAMATE-NMDA-RECEPTOR BLOCKER, ON THE ACTIVITY OF NEURONS OF CATS MOTOR CORTEX DURING THE REALIZATION OF THE FOREPAW PLACING CONDITIONED-RESPONSE

During cats' performance of the forepaw placing reaction, which was co nditioned by a short electrical stimulation (4 msec, 500 Hz) of the co ntralateral parietal cortex (area 5), two types of stimulus-related re sponses could be recorded in the contralateral motor cortex. The prima ry short-latency responses (peak latency about 10 msec, duration up to 30-50 msec) were little sensitive to the application of AP5, a glutam ate-NMDA-receptor blocker. The secondary long-latency responses (peak latency 65 msec, duration up to 150-200 msec) were suppressed in 44% o f cases of AP5 application, The excitatory movement-related resposes w ere suppressed by AP5 in 18% of cases, An increase in the latency of t he conditioned movement itself was observed in 19% of cases, AP5 cause d a decrease in the background firing in 46% of spontaneously active n eurons, The number of cases of enhancement of separate response compon ents and background neuronal activity and the number of cases of a dec rease in the movement latency under the action of AP5 did not exceed t hose expected at random data distribution.