Cerebellar nuclei afferents

The (central) cerebellar nuclei and the lateral vestibular nucleus of Deiters receive the axons of the Purkinje cells of the cerebellar cortex and serve as the main output stations of the cerebellum. The vermis and the flocculus also project to other vestibular nuclei, but here the Purkinje cell axons compete with vestibular root fibers, intrinsic and commissural vestibular connections and projections from the medial cerebellar nucleus and, therefore, are not the dominant afferent system. 

The collateral projections from the lateral reticular nucleus terminate in the same regions of the cerebellar nuclei as the direct spinocerebellar projections. According to Matsushita and Ikeda (1976) they are absent from the lateral cerebellar nucleus in the cat, but according to Dietrichs (1983b) certain parts of the lateral nucleus receive lateral reticular afferents. A weak projection of the lateral reticular nucleus to the lateral vestibular nucleus that was described by Dietrichs and Walberg (1979a) in the cat, recently was confirmed in the rat (Ruigrok et al., 1995). 

Dietrichs E (1983b) Cerebellar nuclear afferents from the lateral reticular nucleus in the cat. Brain Res., 288, 320-324. 

Qvist H (1989a) Tbe cerebellar nuclear afferent and efferent connections with the lateral reticular nucleus in the cat as studied with retrograde transport of WGA-HRP. Anat. Embryo ., 179, 471-483. 

Aspartate is closely related metabolically and chemically to glutamate. In many respects it is difficult to differentiate between aspartate and glutamate as neurotransmitter candidates (Fonnum, 1984). There are, however, some fibers and terminals in which aspartate is regarded as a stronger transmitter candidate than glutamate. These include the cerebellar climbing fibers (Wiklund et al., 1982), hippocampal commissural fibers (Nadler et al., 1978), olfactory tract (Collins and Probett, 1981), cochlear nucleus afferents (Wenthold, 1979), and spinal cord intemeurons (Davidoff et al., 1967)... 

Fig. 5. Drawing of the brainstem depicting neurons and pathways likely to use glutamate as a neurotransmitter. 1 = primary afferent inputs to the dorsal column nuclei (a), the solitary tract nucleus (b), and the cochlear nucleus (c) 2 = granule cell/parallel fibers in the dorsal cochlear nucleus 3 = calyces of Held in the medial nucleus of the trapezoid body 4 = cochlear nucleus inputs to the lateral superior olive 5 = input to the oculomotor nucleus from the ventral lateral vestibular nucleus 6 = input to the oculomotor nucleus from the abducens nucleus 7 = corticocollieular inputs 8 = spinal input to the periaqueductal gray 9 = inputs to the red nucleus and pontine nuclei from the cerebellar nuclei. For further details, see Section 3.3.

Fig. 142, Lateral extension of zone A in the posterior lobe with its projection to the dorsolateral protuberance (dip) of the fastigial nucleus in the rat. The cumulative results of 8 injections of WGA-HRP in the posterior lobe are illustrated. The injection sites are represented as grey areas in B and the corresponding afferent and efferent connections are represented in black in A (inferior olive) and C (cerebellar nuclei), respectively. Dots indicate single labelled neurones in A and few sparsely labelled terminals in C. The lateral extension of the A zone receives a projection from the medial subnucleus c of the caudal medial accessory olive (MAO A2-7). Buisseret-Delmas (1988a)...

Fig. 150. Diagram of the afferent olivocerebellar projection according to Katayama and Nisimaru (1988) and the efferent projection of the zones of the nodulus to the vestibular and cerebellar nuclei according to Wylie et al. (1994) in the rabbit. P = group 8 of the medial accessory olive DC = dorsal cap of Kooy F = fastigial nucleus IP = posterior interposed nucleus MV = medial vestibular nucleus P cell = Purkinje cell SV = superior vestibular nucleus VLO = ventrolateral outgrowth I-VI = zones of rabbit nodulus, numbered according to Katayama and Nisimaru (1988).

Eller T, Chan-Palay V (1976) Afferents to the cerebellar lateral nucleus. Evidence from retrograde transport of horseradish peroxidase after pressure injections through micropipettes. J. Comp. Neurol, 166, 285-302. 

Somana R, Walberg F (1978) Cerebellar afferents from the paramedian reticular nucleus studied with retrograde transport of horseradish peroxidase. Anat. Embryol, 154, 353-368. 

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