Morphological evidence for a vestibulo-thalamo-striatal pathway via the parafascicular nucleus in the rat

We observed by anterograde and retrograde tracing techniques that projectio n fibers originating from the medial vestibular nucleus (MVe) of the rat te rminated in the dorsal two-thirds of the lateral part of the parafascicular thalamic nucleus (PF), where neurons sending their axons to the dorsolater al part of the striatum existed. It was further revealed that the vestibula r fibers made asymmetrical synaptic contacts mainly with dendrites and addi tionally with soma of the striatum-projecting PF neurons. These data sugges t that output signals from the MVe may be transmitted disynaptically to the striatal neurons via the PF neurons. (C) 2000 Elsevier Science B.V. All ri ghts reserved.