The position and organization of motor fibers in the internal capsule found during stereotactic surgery.

Data gathered from exploratory stimulation of the diencephalon in 130 stereotactic operative procedures have been studied, with the aid of a computer graphic technique, to show the position and topography of motor responses in the internal capsule. The results obtained indicate that pyramidal fibers are organized into a rostral-caudal face-arm-leg sequence and occupy a short compact band in the caudal third of the posterior limb of the internal capsule. This is in contrast to previous concepts of the position of these fibers in the capsule.