Comparative cytoarchitectonic study of gudden's tegmental nuclei in some mammals

Abstract

The structure and location of the dorsal and ventral tegmental nuclei of Gudden were studied in brains of 12 species of mammals. The ventral tegmental nucleus of Gudden is composed of oval or polygonal, medium-sized, well-stained cells, and includes the pars principalis situated ventral to the fasciculus longitudinalis medialis, and the pars suprafascicularis in the central gray matter dorsal to the fasciculus longitudinalis medialis (in the golden hamster, mouse, vole, and house shrew). The dorsal tegmental nucleus of Gudden is situated within the central gray matter. This nucleus includes the pars ventralis, composed of oval or triangular cells, medium-sized but smaller than those of the ventral tegmental nucleus of Gudden, and the pars dorsalis, composed of round, small, and lightly stained cells, and often encapsulated by fibers of the fasciculus longitudinalis dorsalis. The isthmus between the dorsal and ventral tegmental nuclei of Gudden is distinct. In the cat, dog, rat, gerbil, and rabbit, the isthmus stands at the dorsal edge of the fasciculus longitudinalis medialis; in the golden hamster, mouse, vole, and house shrew, within the central gray matter; and in the guinea pig, at the ventral edge of the fasciculus longitudinalis medialis. In the green monkey and man, we could not find a ventral tegmental nucleus of Gudden, and in the house shrew and man, the pars ventralis and pars dorsalis of the dorsal tegmental nucleus of Gudden could not be separated.

Connections of the nucleus incertus

“…As mentioned above, some authors have regarded the NIc as a caudal extension of the dorsal raphé nucleus (Taber, 1961;Hayakawa and Zyo, 1983). Our PHA-L evidence indicates that its projection pattern is very distinct from that arising in the NIc (compare Figs.…”

“…As noted above, some authors regard the NIc as a caudal extension of the dorsal raphé nucleus (Taber, 1961;Hayakawa and Zyo, 1983). Therefore, it is important here to provide a comparison between projections of the NIc and what we regard as the caudal dorsal raphé nucleus.…”

“…Meessen and Olszewski (1949) had previously referred to what appears to be the same cell group as nucleus O in the rabbit, and for reasons that will be discussed below, we now designate this cell group the pars compacta (compact part) of the NI (NIc). It is important to note, however, that some authors have extended the boundaries of the dorsal raphé nucleus to include our NIc (Taber, 1961;Hayakawa and Zyo, 1983), although closer analysis reveals that the NIc and caudal dorsal raphé nucleus may be differentiated clearly on both cytoand chemoarchitectonic grounds. Compared to the NIc, caudal regions of the dorsal raphé have smaller and more loosely arranged neurons, some of which are serotonergic, which is not the case in the NIc (Paxinos and Butcher, 1985).…”

The limbic brain: Continuing resolution

“…As is well known, cholinergic sleep systems, both ascending and descending, extend across this entire anterior limbic territory (limbic cholinergic system). Petrovický (Petrovický, 1971(Petrovický, , 1973(Petrovický, , 1985a and others (Hayakawa and Zyo, 1983;Irle et al, 1984) have precisely identified the cytoarchitecture and connections of Fig. 3.…”

Insectivora

“…Histology, Histochemistry, Fiber Connections Stephan (1961, 1966b, SEP, Crocidura) Bauchot (1963, DIE, Crocidura) Girod (1976, HYP, Suncus) Hayakawa and Zyo (1983, tegmentum, Suncus) Hayakawa and Zyo (1984, tegmen to-mammillar connections, Suncus) Isomura et a1. (1986 Mohanty and Kar (1982, biochemistry, Suncus) Naik and Dominic (1971, HYP, Suncus) Rehkamper (1981, NEO, Crocidura) Schwerdtfeger (1984, HIP, Crocidura) Sigmund et a1.…”