Neural mechanisms of the chloralose jerk with special reference to its relationship with the spino-bulbo-spinal reflex.

It is known that animals anesthetized with chloralose exhibit a generalized jerky muscular contraction in response to various stimuli6). Since this contraction is abolished by acute spinal cord transection, it seems that supraspinal structures may be necessary for its development1,6). With electromyographic observations, there is a late response as well as an early reflex which corresponds with segmental spinal reflex responses1). Recent workers8,9) have investigated the spino-bulbo-spinal (SBS) reflex system, which interconnects spinal and medullary segments. This SBS reflex appeared as a late response, which was abolished by an acute spinal cord transection. It seemed possible that the same neurones involved in the chloralose contraction may be active in the production of the SBS reflex. Therefore, an attempt has been made to analyze the neural mechanisms of the "chloralose jerk "with special reference to its interactions with the SBS reflex in cats.