Arrest reaction in man: motor arrest response by electrical stimulation of the deep structure of the cerebrum

In spite of many reports of arrest reaction in animals, there are very few reports in man. During a therapeutic stereotactic operation we observed peculiar phenomena caused by electrical stimulation to the deep structure of the cerebrum. The electrical stimulation caused an interruption of counting and other motor actions, which could be resumed following release of stimuli. In almost all cases psychic confusion of memory disturbances were not observed. The head of the caudate nucleus and its adjacent white matter cause arrest reaction with the lowest threshold of 5 V; on the other hand, substantia medullaris lobi frontalis, radiatio corporis callosi and nucl. reticularis oralis of the thalamus caused arrest reaction with the highest threshold of 10--15 V. The arrest reaction that we observed is thought to be due to a direct effect on the head of the caudate nucleus, not due to secondary effects on the internal capsule and the motor fiber in the vicinity of the caudate nucleus. However, the possibility that the current spread to the motor fiber cannot be definitely ruled out.