Topographical representation of vascular smooth muscle of limbs in primate motor cortex

Abstract

Changes in limb blood flow in monkeys anesthetized with chloralose were studied during electrical stimulation of a cortical site in area 4 which produced movement of one limb. After location of the stimulation site, further movement was prevented either by section of splnal nerves below the major autonomic outflow or by administration of decamethonium bromide. Cortical stimuli at the locus previously producing movement then induced a 10-50% increase in mean blood flow in the same limb. Usually, blood flow in the opposite extremity and in the other extremity of the same side (e.g., right arm vs. right leg) either was unchanged or decreased slightly. Mean arterial blood pressure was either unchanged or reduced by 5-10 mm Hg, and the heart rate was generally unchanged. Occurrence of similar responses in the skinned limb suggests that the specific increase in flow is to the muscle.