The vestibulothalamic projections in the cat studied by retrograde axonal transport of horseradish peroxidase

Abstract

Horseradish peroxidase (HRP) was injected or iontophoretically ejected in various thalamic nuclei in 63 adult cats. In 11 other animals HRP was deposited outside the thalamic territory. The number and distribution of labelled cells within the vestibular nuclear complex (VC) were mapped in each case. To a varying degree all subgroups of VC appear to contribute to the vestibulothalamic projections. Such fibres are distributed to several thalamic areas. From the present investigation it appears that generally speaking, there exist three distinct vestibulothalamic pathways with regard to origin as well as to site of termination of the fibres. One projection appears to originate mainly in caudal parts of the medial (M) and descending (D) vestibular nuclei and in cell group z. This pathway terminates chiefly in the contralateral medial part of the posterior nucleus of the thalamus (POm) including the magnocellular part of the medial geniculate body (Mgmc), the ventrobasal complex (VB) and the area of the ventral lateral nucleus (VL) bordering on VB. A second projection originates mainly in the superior vestibular nucleus (S) and in cell group y and terminates mainly in the contralateral nucleus centralis lateralis (CL) and the adjoining nucleus paracentralis (Pc). A third, more modest, pathway originates chiefly in the middle M and D, with a minor contribution from S and cell group y, and terminates in the contralateral ventral nucleus of the lateral geniculate body (GLV). There is some degree of overlap between the origin of these three vestibulothalamic pathways.

The thalamocortical vestibular system in animals and humans

“…The ventral posterior lateral nucleus (VPL) and the nucleus ventralis intermedius (Vim, a transitional zone between the VPL and the ventrolateral thalamic nuclei, see Shiroyama et al, 1999) receive vestibular inputs (Blum et al, 1979b;Blum and Gilman, 1979;Büttner and Henn, 1976;Deecke et al, 1977;Kotchabhakdi et al, 1980;Lang et al, 1979;Magnin and Fuchs, 1977;McCrea, 2008a, 2008b;Matsuo et al, 1994Matsuo et al, , 1995Matsuo et al, , 1999Meng et al, 2007;Nagata, 1986;Sans et al, 1970;Shiroyama et al, 1999) (Fig. 1A-B).…”

“…Anatomical studies revealed vestibular projections to the ventroanterior thalamic nucleus (VA) and mostly to the ventrolateral thalamic nucleus (VL) [VA-VL complex] in the cat (Condé and Condé, 1978;Kotchabhakdi et al, 1980;Maciewicz et al, 1982;Nakano et al, 1985;Raymond et al, 1974Raymond et al, , 1976Sans et al, 1970), rat (Nagata, 1986;Shiroyama et al, 1999) and macaque monkey (Lang et al, 1979). Studies conducted in the cat and in the rat showed that the VA-VL complex receives vestibular afferents from the MVN and SVN via the medial longitudinal fasciculus, the ascending tract of Deiters and the superior cerebellar peduncle (Kotchabhakdi et al, 1980;Maciewicz et al, 1982;Nagata, 1986;Nakano et al, 1985;Shiroyama et al, 1999).…”

“…Studies conducted in the cat and in the rat showed that the VA-VL complex receives vestibular afferents from the MVN and SVN via the medial longitudinal fasciculus, the ascending tract of Deiters and the superior cerebellar peduncle (Kotchabhakdi et al, 1980;Maciewicz et al, 1982;Nagata, 1986;Nakano et al, 1985;Shiroyama et al, 1999). Projections from the DVN and, to a lesser extent, from the lateral vestibular nucleus (LVN) have also been identified in the cat (Kotchabhakdi et al, 1980;Maciewicz et al, 1982). It has been demonstrated in the Rhesus monkey that the VL also receives vestibular afferents from the vestibular cerebellar nuclei (fastigial nucleus, dentate nucleus, anterior interposed nuclei; see Meng et al, 2007) (Fig.…”

“…Regarding vestibular processing, anatomical studies have stressed the importance of the centromedian nucleus (or parafascicular nucleus in the rat), the central lateral nucleus, and the paracentral nucleus (Blum et al, 1979b;Blum and Gilman, 1979;Kotchabhakdi et al, 1980;Lai et al, 2000;Magnin and Kennedy, 1979;Matsuo et al, 1994;Meng et al, 2001Meng et al, , 2007Nagata, 1986;Raymond et al, 1976;Shiroyama et al, 1995). The centromedian/ parafascicular nucleus receives vestibular information mainly from the MVN bilaterally, with an ipsilateral dominance, and from the SVN and the DVN ipsilaterally (Lai et al, 2000;Matesz et al, 2002;Shiroyama et al, 1995).…”

Vestibular Signals in Primate Thalamus: Properties and Origins

“…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.…”