THE VESTIBULOTHALAMIC PROJECTIONS IN THE RAT STUDIED BY HRP TECHNIQUE / 解剖学报

ABSTRACT

Horseradish peroxidase(HRP)was injected in 41 rats to investigate thevestibulothalamic projections.Labelled neurons were observed in various subdivisionsof the vestibular nuclear complex following injections of the ventral anterior nucleus(VA),the ventral medial nucleus(VM),the central lateral nucleus(CL),the ventralposterior nucleus(VP),the nucleus posterior thalami(PO),the magnocellular partof the medial geniculate body(MGBmc),and the ventral nucleus of the lateralgeniculate body(LGV).From the present investigation it appears that generallyspeaking,there exist two distinct categories of vestibulothalamic projections withregard to origin as well as site of termination of the fibers.The first Category ofprojections appears to originate from all four vestibular nuclei(superior,lateral,medial,and descending)and terminate in the nonspecific thalamic nuclei includingVA,VM,and CL.It may be concerned with regulation of the general excitabilityof neurons in cortex and participation in motor performance.The second categoryof projections appears to originate only from the medial and descending vestibularnuclei and terminate in the ventral posterior nucleus and posterior group of thethalamus(including PO,MGBmc,and LGV).It may be associated with consciousvestibular perception and convergence of vestibular and somatic impulses.