Projections of the vestibular nuclei to the thalamus in the rat: A Phaseolus vulgaris leucoagglutinin study

Abstract

Injections of the anterograde axonal tracer Phaseolus vulgaris leucoagglutinin were made into individual nuclei of the vestibular nuclear complex of the rat to identify specific projections to the thalamus. The results showed that the superior vestibular nucleus and the medial vestibular nucleus, especially its rostral-to-middle parts, project to the lateral part of the parafascicular thalamic nucleus (corresponding to the centromedian nucleus in primates), the transitional zone between the ventrolateral thalamic nucleus (VL) and the ventral posterolateral thalamic nucleus (VPL) (the region considered to be the nucleus ventralis intermedius of Vogt [Vogt C. 1909. La myeloarchitecture du thalamus du cercopitheque. J Psychol Neurol 12:285-324.]), the lateral part of the centrolateral thalamic nucleus and the dorsal part of the caudal VL; the spinal vestibular nucleus projects to the lateral part of the parafascicular thalamic nucleus, the transitional zone between the VL and the VPL, the caudal part of the ventrobasal complex, and the suprageniculate thalamic nucleus. These results suggest that vestibular information is transmitted not only to the cerebral cortex (mainly area 2V and area 3a) but also to the striatum. They also suggest that vestibular activity may affect gaze control by means of vestibulothalamocortical pathway in addition to vestibulo-ocular and vestibulopremotoneuronal routes.

Vestibular Signals in Primate Thalamus: Properties and Origins

“…Consequently, we hypothesized that either primate vestibular nuclei inputs are actually more broadly distributed, like those of rodents (Nagata, 1986;Shiroyama et al, 1999), or that the thalamus might receive vestibular information from areas other than the VN. Because vestibular signals in VPL presumably originate from its VN input , we aimed an injection at a region dorsal to VPL to retrogradely label its inputs.…”

“…Widespread, bilateral thalamic projections from the vestibular nuclei (VN) have been reported in the rat (Nagata, 1986;Shiroyama et al, 1995Shiroyama et al, , 1999 and cat (Kotchabhakdi et al, 1980;Maciewicz et al, 1982;Nakano et al, 1985). However, the projection in primates appears to be more discrete.…”

Latency of vestibular responses of pursuit neurons in the caudal frontal eye fields to whole body rotation

“…These thalamic areas project to the frontal cortex including FEF (Shiroyama et al 1999). Ebata et al (2004, using the laminar field potential analysis, suggested that vestibular-evoked potentials in the caudal FEF of monkeys were directly conveyed to the cortex through the thalamus, consistent with the anatomical studies (Shiroyama et al 1999).…”

Squirrel Monkeys and Space Motion Sickness

“…The efferent and afferent connections of the vestibular nuclei were important and were therefore intensively studied in rat [42], squirrel monkey [43,44], cat, and monkey [45,46]. Spinocerebellar afferents were studied in the rat, cat, and squirrel monkey [47], as well as the otolith pathways [48].…”

“…Coerulovestibular pathways were also studied in rats, rabbits, and monkeys [49]. Figure 1 demonstrates the essence of the innervation focused on the vestibular nuclei [42].…”