DECUSSATIONS OF SYMPATHETIC EFFERENT PATHWAYS FROM THE HYPOTHALAMUS

Abstract

The hypothalamus of 8 unilaterally sympathectomized cats was stimulated before and after hemisection of the contralateral cervical cord for estimating the crossed and uncrossed components of the cervical sympathetic, vasomotor and adrenal efferent pathways in the brain stem and cord. The impulses were found to descend to the spinal cord uncrossed or crossed in the brain stem or in the spinal cord. They also reached the ipsilateral half of the cord below a hemisection via connections in the brain stem and spinal cord. The connections in the spinal cord were probably effected by the spinal commissural system.