The Medial Nuclei

Abstract

For reasons that are rather arbitrary, though based on historical precedent, I consider the medial nuclear complex to consist of the mediodorsal nucleus, the parataenial nucleus, and the medioventral (reuniens) nucleus (Figs. 13.1 and 13.3). J. E. Rose (1942a,b) originally made this definition on the grounds that the three nuclei develop from a common pronuclear mass that is subsequently split by the growth of the intralaminar nuclei (his central commissural system) (see Fig. 6.10). Prior to Rose’s work, “medial group” was ill-defined and often included parts of the rostral and caudal intralaminar nuclei, anteromedial nucleus, submedial nucleus, and principal ventral medial nucleus (von Monakow, 1895; Vogt, 1909; Friedemann, 1911; Nissl, 1913; M. Rose, 1935; Walker, 1937, 1938a). Perhaps as J. E. Rose (1942b) intimated, the submedial nucleus should be regarded as an extension of the medioventral nucleus and thus included in the medial group because, like the mediodorsal nucleus, it receives olfactory inputs (Price and Slotnik, 1983). On the other hand, it also receives spinothalamic inputs (Craig and Burton, 1981; Burton and Craig, 1983; Mantyh, 1983) and because of this, I have chosen to include it in the ventral medial group of nuclei (Chapter 7).

The progressive relative enlargement of the frontal lobes in the phylogenetic scale is by no means so conspicuous as that of the parietal or the temporal lobes. This fact though it does not disprove the preoccupation of the frontal lobes with emotional and personality integration, casts doubt on the common assumption that these lobes are man’s greatest developmental achievement and therefore likely to be particularly concerned in his highest mental activities. Le Gros Clark (1948)