CEREBELLAR CORTICAL AFFERENTS FROM THE PERIAQUEDUCTAL GREY (PAG) IN THE RAT——A HRP STUDY / 解剖学报

ABSTRACT

A cerebellar afferent connection from the periaqueductal grey (PAG) has been demonstrated in the rat by means of retrograde transport of horseradish peroxidase (HRP) in the present study. The projection is bilateral, but the projection from the ipsilateral side is predominant (31). Its main origin is the ventromedial and ventrolateral regions of middle and caudal parts of PAG (98.8％), and the fibers reach different cerebellar cortical regions culmen, declive, folium vermis, tuber vermis, pyramis vermis, uvula vermis, lobulus quadrangularis, crus Ⅰ, crus Ⅱ, and paraflocculus. Most labelled neurons are medium sized, but some small neurons also appear to project to cerebellum. Only a few large neurons are retrogradely labelled at the most caudal end of the caudal part. Functionally, both cerebellum and PAG are related to visceral activities. Consulting the present experiment, we discussed the significant role of the PAG-cerebellar projection.