Neuronal activity in primate striatum and pallidum related to bimanual motor actions

To assess whether striatal and pallidal neurones may contribute to bimanual co-ordination, two macaque monkeys were trained to perform a delayed conditional sequence of co-ordinated pull and grasp movements, executed either bimanually or unimanually. Most of the 58 task-related neurones, recorded from the caudate nucleus, putamen, external and internal divisions of the globus pallidus, exhibited an activity related to the execution of the movements. Only a quarter of neurones displayed preparatory activity. The majority of units exhibited a significant modulation of activity in unimanual trials irrespective of the hand used to perform the task. In bimanual trials, one-third of units exhibited discharge patterns reflecting a bimanual synergy, suggesting a possible role for basal ganglia in inter-limb co-operation.