PROJECTIONS OF DIENCEPHALON ONTO THE MESENCEPHALIC PERIAQUEDUCTAL GRAY MATTER IN THE RAT / 解剖学报

ABSTRACT

The projections of diencephalon onto the rostral part of the mesencephalic periaqueductal gray matter (PAG) were investigated by using the method of retrograde transport of HRP in the rat. The results have led to following conclusions:1. The diencephalic afferents to the rostral part of PAG originate mainly from medial preoptic area, anterior hypothalamic area, dorsomedial and ventromedial hypothalamic nuclei, dorsal premamillary nucleus, lateral hypothalamic region, Forel's field and zona incerta ipsilaterally, and a few of them originate contralaterally.2. The anterior hypothalamic area, ventromedial hypothalamic nucleus, dorsal premamillary nucleus and zona incerta project more to the ipsilateral nucleus lateralis of PAG than to the nucleus medialis and contralateral nucleus lateralis of PAG.3. In the anterior hypothalamic area, a large number of neurons projecting to PAG was located in the lateral anterior nucleus.4. In the lateral hypothalamic region, the lateral preoptic area and anterior division project to both nuclei lateralis and medialis, while its tuberal and mamillary divisions probably project only to nucleus lateralis.