Abstract
1. Experiments were performed on 26 adult cats under chloralose anesthesia, in order to investigate whether a relationship exists between the neural mechanisms of the chloralose jerky reaction and the spino-bulbo-spinal (SBS) reflex.
2. A single tactile stimulation to the skin over the body yielded early and late responses from the spinal motor nerves and muscles.
3. The early one, which was apparently due to the segmental spinal mechanisms, was not concerned in the chloralose jerky muscular reaction.
4. The late response may be related to the chloralose jerky muscular reaction. Characteristics of the late response may be summarized as follows: a) On weak stimulation, the late response was recorded mainly from flexor motor nerves. b) The late response was obtained from the spinal ventral roots at different levels along the spinal cord. Its latency became steadily shorter as one recorded from segments closer to the brainstem. c) The conduction velocity of the descending pathway in the late response was about 30m/sec. d) After spinal transection, the late response was completely abolished. e) Pentobarbital sodium anesthesia affected the late response at dosage levels of about 3mg/kg.
5. Above noted observations were almost the same as those of the SBS reflex This suggests that some part of the neural mechanisms of the chloralose jerky muscular reaction may be the same as those of the SBS reflex.
