An observation on hitherto unknown corticospinal fibers that descend between the tractus corticospinalis lateralis and ventralis in the cat

Abstract

Following injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) into the pericruciate (sensorimotor) cortex on one side in the cat, we found labeled fibers surrounding the ventral horn of the spinal cord bilaterally, in addition to the crossed and the uncrossed lateral, ventral and dorsal corticospinal tracts (CSTs). These hitherto unknown fibers, which could be traced to the caudal end of the L2 segment, were predominantly contralateral to the WGA-HRP injection side. This study indicates the presence of newly recognized CST fibers in the cat.