While we have a fair understanding of how and where forelimb-hand manipulat
ive movements are controlled by the neocortex, due to functional imaging st
udies, we know little about the control of bipedal movements such as walkin
g because of technical difficulties. We succeeded in visualizing cortical a
ctivation patterns of human gait by measuring relative changes in local hem
oglobin oxygenation using a recently developed near-infrared spectroscopic
(NIRS) topography technique. Walking activities were bilaterally associated
with increased levels of oxygenated and total hemoglobin in the medial pri
mary sensorimotor cortices and the supplementary motor areas. Alternating f
oot movements activated similar but less broad regions. Gait imagery increa
sed activities caudally located in the supplementary motor areas. These fin
dings provide new insight into cortical control of human locomotion. NIRS t
opography might be also useful for evaluating cerebral activation patterns
during pathological gait and rehabilitative intervention. (C) 2001 Academic
Press.