Performance of manual copying tasks after focal cortical lesions.

Patients with unilateral frontal or temporal excisions and normal control subjects were required (1) to copy single, difficult positions of the arm, fingers, or both, and (2) to copy the experimenter as three hand positions were presented one after the other at an increasing rate. All patient groups were impaired relative to the control group on both tasks, but on the second task patients with frontal lesions were also impaired relative to those with temporal lesions. Results suggested a role of the left-and right-frontal lobes in rapid execution of multiple manual responses.