THE AVERAGED EVOKED POTENTIALS (AEPS)SN THE SPINAL CORD ELICITED BY ELECTRICAL STIMULATION OF THE HYPOTHALMUS AND ZONA INCERTA IN THE RAT
- VernacularTitle:电刺激大鼠下丘脑及不定带引起的脊髓平均诱发电位
- Author:
Yingxia WENG
- Publication Type:Journal Article
- From:
Academic Journal of Second Military Medical University
1983;0(S1):-
- CountryChina
- Language:Chinese
-
Abstract:
Sixty-four rats anaesthetized with urethane and immobilized with flaxedil were used in this experiment.54 responses of AEPs, which have fixed latency and uniform wave, -were recorded with a fine electrode of diameter 40?m in some areas of the ipsilateral cervical and thoracic spinal cord by stimulating the hypothalamus and zona interta. The stimulation points.eliciting responses were located at the midld elevel of the hypo-thaiamus, especially around the fornix and in the lateral hypothalamus .A few of them were on the lateral side of the paraventricular nucleus(FVH)and posterior hypotha-la-mus.The responses were recorded mostly in the ventral horn and antero-lateral funicu-lus in the spinal cord, and were some what evenly distributed in the other parts except in the dorsal columns and the dorso-lateral funiculus.Spinal AEPS produced by stimulating lateral hypothalamus or zona incerta were alike.A number of spike-like AEPs with duration less than 1.5 ms could follow paired electrical stimulation with a frequency higher than 200 Hz, was resistent to asphyxia and recovered faster when respiration was reinstituied.Those AEPs might be the sign indicating a direct fiber connection be-ween the hypothalamus or zona incerta and the spinal cord.The conduction -velocities along these pathways, calculated from the distances between the stimulating and recording sites and the response latencies were mostly 4-6 m/s, which fell within the range of the conduction velocity of A-fibers in peripheral nerves.Only in one case the veloc-fty was coincided with that of peripheral c fibers.Other AEPs, which have shown a iollowing frequency of less than 200 Hz to paired stimulation, would suggest someoli-gosynaptic or monosynaptic pathways from the stimnlating to the recording areas.Results obtained after sectioning the spinal cord indicated that some fibers directly conne ting the lateral hypothalamus or zona incerta and the spinal cord might run along che ventral part of the spinal cord.On the basis of the known anatomical data, the ditrect fiber connection between the hypothalamus and the spinal cord, confirmed by electro-physiological methods in our study, would suggest the direct projection from the hypothalamus to the spinal cord.
