Simple and complex spike activities of the cerebellar Purkinje cell in relation to selective alternate movement in intact monkey

Abstract

Two adult monkeys ( Macaca mulatta ) were trained to perform a selective alternate movement (SAM) by a hand in either side of the body. To obtain a reward, a monkey had to select one of 4 kinds of the movement. After 16 trials of this correct movement, one of the remaining 3 was chosen to be a next correct one which the monkey should find out. This procedure was repeated in a pseudorandom fashion from one movement to another. Discharges of single cerebellar Purkinje cells (P-cells) were recorded during hand still and during the performance by a hand ipsi-lateral (I. SAM) or contra-lateral (C. SAM) to the recording side. Fifty-seven P-cells were found in the lateral hemisphere of the lobulus simplex and the crus I as well as in the intermediate zone of the culmen, and were judged to be specifically related to the ipsi-lateral hand movement. Firing patterns of the simple spike (SS) and the complex spike (CS) were analyzed quantitatively in 21 of these P-cells by the modal interval, mean interval, standard deviation and the coefficient of variation. These parameters for the SS changed during I. SAM compared to those during the hand still and C. SAM. The values for the CS in most P-cells were identical in these 3 states, but in 4 P-cells only a tonic change of the CS activities was observed during I. SAM. None of P-cells showed phase-locked change of the CS activities in relation with the SAM, regardless of recorded location of a P-cell.