Activity of Neurons in Area 4 and in Area 5 of Monkey During Operant Conditioning of a Flexion Movement

Summary

Present data concern changes of neuronal activity in Area 4 and Area 5 of macaca Speciosa, during shaping of a self initiated flexion movement of the elbow without sensory cues. Two behavioral changes occur during this period and are quantified:increase in the frequency of movements and change in the shape (amplitude, muscular contraction of biceps and triceps). The authors propose a model to quantify neuronal patterns whose changes are compared with the changes in behavior. Two sets of neurons are described, one more active with the flexion movement, the other active with the taking of the reward by the ipsilateral arm; there is an important spatial overlap between them. Neurons active both with conditioned movement and taking of the reward can show an enhancement of their activity when the first series of movements appear. An increase in the regularity of the conditioned movement corresponds to a balance between the two sets described. Cells whose activity is maximal with the conditioned movement show changes parallel with performance. During the sessions in which there is an increase in the accuracy of the movement, some cells show an increase in activity at the onset of the flexion movement.