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Effect of cooling or ablation of the culmen of cerebellar vermis on “stepping automatism”in guinea pigs

Liu Shiyi, Zhang Wenyuan, Wang Zeshen

Shanghai Institute of Physiology, Academy Sinica. Shanghai, China；Shanghai Institute of Materia Medica, Academy Sinica. Shanghai, China

Abstract

The present paper concerns investigation of the effect of partial cooling or ablation of the culmen of the cerebellar vermis on “stepping automatism” inntact guinea pigs. Regular "stepping automatism" was induced via our recently reported SIS (Substances capable of Inducing Stepping)[(4-R-2,2,5,5-tetrakis (trifluoromethyl)-imidazoline)].Results show that partial cooling or ablation of the culmen (V and IV lobules) and centralis(III a, b) of the cerebellar vermis significantly facilitated SIS-induced "stepping automatism" in guinea pigs. Cooling of the cerebellum could only modulate but not trigger stepping movements. This modulation was most prominent in those guinea pigs exhibiting weak "stepping automatism". It is worthy of note that the culmen of cerebellar vermis modulated both left and right forelimbs simultaneously, whereas the lateral part of culmen of cerebellar vermis and hemisphere predominantly modulated ipsilateral forelimb. Results show that when the interfacial temperature between the cooling probe and tentorium cerebelli was appropriate (5℃-0℃), the effects of partial ablation could be very largely mimicked.

Key words: SIS [(4-R-2,2,5,5-tetrakis (trifuoromethyl)-imidazoline)];Cerebellum;Cooling;Ablation;Stepping automatism;Guinea pig

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Citing This Article：

Liu Shiyi, Zhang Wenyuan, Wang Zeshen. Effect of cooling or ablation of the culmen of cerebellar vermis on “stepping automatism”in guinea pigs. Acta Physiol Sin 1987; 39 (5): (in Chinese with English abstract).