前庭神経核群のy-groupについて
1986 年 45 巻 3 号 p. 256-259
詳細
1986 年 45 巻 3 号 p. 256-259
Our previous studies concerning the cat's y-group were reviewed. Anatomical experiments using retro-grade axonal transport of horseradish peroxidase demonstrated projections from the cerebellar floccular caudal-zone to the y-group. Electric stimulation of the y-group produced the upward eye movement, while destruction eliminated the downward eye movement elicited by electric stimulation of the caudal-zone. The neuronal pathway mediating the downward eye movement was then investigated with the use of systematic microstimulation techniques. It was found that target neurons of caudal-zone inhibition project to the oculomotor neurons innervating the contralaterai rectus muscles and the ipsilateral inferior oblique muscles via 'crossing ventral tegmental tract'. Differences in the neuronal connections between the dorsal (DY) and ventral (VY) subdivisions of the y-group were then investigated. It was found that 1) target neurons were located in the DY, and about half of these neurons received vestibular nerve inputs polysynaptically; 2) in the VY, on the other hand, most neurons received monosynaptic vestibular nerve inputs, and some of these neurons projected to the flocculus.
