聴覚誘発眼輪筋反射に関する電気生理学的研究第2編-中枢神経系の破壊および切断実験-

Abstract

The pathway of the blink reflex elicited by auditory stimulation was investigated by means of destructions and transections in some parts of the central nervous system. The reflex was recorded as microvibrations of the eyelid (auditory-evoked eyelid microvibration, AMV).1) Bilateral electric lesions in the midbrain reticular formation resulted in a marked re duction or a disappearance of AMV.2) Lesions in the inferior colliculus reduced the amplitude of AMV, while lesions in the medial geniculate body had no effect.3) Temporal suppression of the cerebral cortex by KCI solution did not reduce the amplitude of AMV, but sometimes increased it. The same result was obtained after mechanical destruction including the hippocampus.4) The transecti ons of the brainstem at both the intercollicular and upper medullary level did not affect AMV. On the other hand, AMV disappeared after the transection at the postcollicular level.5) The se results suggest that the reflex pathway of AMV exists between lower midbrain and upper medulla, including the classical auditory pathway, peripheral to the inferior colliculus. AMV has a close relation to the function of the midbrain reticular formation, but does not have a direct relation to the cerebral cortex.6) AMV will be useful in evalua ting the function of the brainstem. Furthermore, MV (photo-evoked eyelid microvibration) is preferable to record in combination, to certify the localization of the lesion in the brainstem.