Converting a spinal CR into a reflex.

Abstract

Records are presented from 5 dogs in which a spinal conditioned response (CR) of the insertional end of the semitendinosus M. to tail shock came to involve the whole M. and assumed the reflex property of inextinguishability, while retaining other characteristics of learned responses, when all contralateral ventral roots posterior to the spinal transec-tion had been severed. This conversion of a spinal CR into a reflex is interpreted as supporting the theory that persistent contralateral inhibitory mechanisms operate in both learned and reflex responses in the spinal dog.