A Comparative Neuroanatomical Study of the Red Nucleus of the Cat, Macaque and Human

Abstract

BackgroundThe human red nucleus (Nr) is comparatively less well-studied than that of cats or monkeys. Given the functional importance of reticular and midbrain structures in control of movement and locomotion as well as from an evolutionary perspective, we investigated the nature and extent of any differences in Nr projections to the olivary complex in quadrupedal and bipedal species. Using neuroanatomical tract-tracing techniques we developed a “neural sheet” hypothesis allowing us to propose how rubro-olivary relations differ among the three species.Methods and FindingsWheat germ agglutinin-horseradish peroxidase staining supports findings that the cat's nucleus accessories medialis of Bechtrew (NB) projects mainly to the lateral bend of the principal olive. We clarified boundaries among nucleus of Darkschewitsch (ND), NB and parvicellular red nucleus (pNr) of the cat's neural sheet. The macaque's ND-medial accessory olivary projection is rostro-caudally organized and the dorsomedial and ventrolateral parts of the macaque's pNr may project to the principal olive's rostral and caudal dorsal lamella; in cat it projects as well to pNr. Myelin- and Nissl-stained sections show that a well-developed dorsomedial part of the human Nr consists of densely packed cells, deriving small myelinated fibers that continue into the medial central tegmental tract.ConclusionsBased on these findings we suggest there are distinct bipedal-quadrupedal differences for Nr projections to the olivary complex. We propose the Nr of cats and monkeys comprise the ND, NB and pNr in a zonal sheet-like structure, retaining clear nuclear boundaries and an isolated, well-developed mNr. The human NB may be distinguished from its more specialised ND (ND lies alongside a well-developed pNr) in the human central gray. Phylogenetically, the NB may have been translocated into a roll-shaped Nr in the reticular formation, the dorsomedial portion of which might correspond to the cat's and monkey's NB.

Carbocyanine Dye Usage in Demarcating Boundaries of the Aged Human Red Nucleus

“…We further demonstrated the possibility of the translocation of the position of the human NB from the ventral central gray to the dorsomedial part of the human pNr (Onodera and Hicks, 2009 [8]). The human ND is isolated in the ventral central gray and occupies the MTT as does the feline ND (in human: see especially Case 1 in Fig.…”

“…We offered the view that in humans, the nucleus accessorius medialis of Bechterew is not an integral part of the ventral central gray, like it is in the cat and monkey, but that it corresponds to the dorsomedial part of the Red nucleus (Onodera and Hicks, 2009 [8]). By this translocation of the human NB, fine myelinated fibers from the human NB occupy the medial part of the CTT (as demonstrated by the present DiI study) in contrast to the situation in felines, where the NB occupies an area within the MTT (Onodera, 1984 [7]).…”

Thalamic interactions of cerebellum and basal ganglia

“…Nigral and cerebellar projections have been shown to converge on neurons of the superior colliculus in the rat (Westby et al 1994). Similarly, these two structures seem to interact in the reticular formation (ShammahLagnado et al 1983(ShammahLagnado et al , 1987(ShammahLagnado et al , 1992Schneider et al 1985) and the nucleus of Darkschewitsch, which has been associated with the red nucleus based on its similar connectivity patterns (Onodera and Hicks 2009, 1998. The involved nuclei in the thalamus-that is, MDpl and CM/Pf-receive input from all structures mentioned here in the context of the assumed oculomotor network (Ono and Niimi 1986;Royce et al 1991;MacLeod and James 1984) and project to the frontal eye fields (Sadikot and Rymar 2009;Tanaka and Kunimatsu 2011).…”

Cerebellum and Cerebellar Connections

“…Rutherford and colleagues (1984) noted that the inferior olive of the rat does not receive afferents from either the magnocellular or parvicellular parts of the red nucleus, regions as defined in the atlas of Paxinos and Watson (2014). This suggested that nomenclature used in different species does not reflect homologous structures Onodera and Hicks, 2009). The IODM receives input from the spinal trigeminal nucleus (Huerta et al, 1983;De Zeeuw et al, 1996).…”