Abstract
In order to clarify the functional significance of the afferent average evoked potentials caused by sciatic nerve stimulation, their fundamental experiments were made by using rabbits.
1. As the result of the sciatic nerve stimulation, responses were observed in the following manner,3 negative responses (N1, N2 and N3) 1 positive response (P) and 2 negative responses (N4, N5) in cerebral cortex.
2. The intravenous injections of barbiturate, chlorpromazine, myanesin, morphine and pentazocine, and the application of procaine on the peripheral nerve displayed an inhibitory action on such early components as N1, N2 and N3.
3. By the application of the sciatic nerve stimu lation,3 small negative responses (HN1, HN2 and HN3), followed by 2 large negative responses (HMI, HN5) w ere observed in the hippocampus.
4. The pain ting of procaine on the peripheral nerve produced a strong inhibitory action on all the components of the afferent average evoked potential in the hippocampus.
5. The painting of procaine hardly acted on H wave and M wave of the spinal reflex,. but strongly inhibited the evoked muscular discharge by nociceptive reflex.
6. The lesion of VPM and VPL showed an inhibitory effect on th e early components of the afferent average evoked potential recorded from the cerebral cortex.
7. The lesion of VA, DM, VM and CM showed an inhibitory effect on such late components as P, N4 and N5.
8. The lesion of CG in hibited not only the early components of the afferent average evoked potential, but also their late components.
9. All the components of the affere nt average evoked potential in the hippocampus were inhibited by the lesion of VA, DM, VM, CM, VPM, VPL and CG.
As the results of the above various experiments, considerations h ave been given to the fact that N1 and N2 components of the afferent average evoked potential in the cerebral cortex appear after going up the afferent pathway which transmits a perception In, f rom the peripheral to the central, while N4 and N5 components appear via the central nuclei belonging to the diffuse thalamocortical projection system, and that these nuclei are also concerned with the appearance of the afferent average evoked potential in the hippocampus.
