Response time in monkeys with unilateral neglect
E. Valenstein, R. T. Watson, T. Van den Abell, R. Carter and K. M. Heilman
Four monkeys were trained to open a door with either the right or left hand
in response to a tactile stimulus to either leg. After unilateral frontal
arcuate ablation inducing unilateral neglect, the response time on this
task increased most when the monkey responded with the hand contralateral
to the lesion, but also increased when the monkey used the hand ipsilateral
to the lesion. The side of stimulation had no effect on response time.
Control (anterior superior temporal) lesions did not cause neglect and only
affected response time slightly in one monkey (using the limb contralateral
to the lesion). We conclude that response time is increased in animals with
unilateral neglect and that the increase results from a defect in intention
to act (motor neglect) rather than from sensory neglect.
