New Model of Human Red Nucleus Figure 14. Three-dimensional models of red nucleus. The mesodiencephalic nuclei of the cat (A), the macaque (B), and the human (C) as reconstructed using serial sections shown in Fig. 1 for cat; Figs. 7,8 and 11 for macaque; and a myelo- and cytoarchitectonic analysis in Figs. 10–12 for human. The rostral ends of these modeles toward left side. dmpNr–dorsomedial part of parvicellular red nucleus, EW–Edinger-Westphal nucleus, FR– fasciculus retroflexus, mNr–magnocellular red nucleus, NB–nucleus accessorius medialis of Bechterew, ND–nucleus of Darkschewitsch, vlpNr– ventorlateral part of parvicellular red nucleus, III–oculomotor nucleus. doi:10.1371/journal.pone.0006623.g014 shell. The chimpanzee mNr shows a similar feature as the human semilunar shell: i.e., populations of coarse and fine neurons occupying distinct and separate areas within a small junctional zone [44]. Recent studies concerning the human fetal mNr showed that this structure develops progressively during the latter half of gestation and that the mNr is more prominent in fetal stages than in adulthood (Ulfing and Chan, 2001; 2002 [12,13]; Yamaguchi and Goto, 2006 [14]). The fetal mNr drapes around the caudal third of the pNr in the form of a semi-lunar shell, and it and the pNr are clearly separated from each other. Pompeiano and Brodal (1957) pointed out the possibility of underestimates having been made of the extent of the human PLoS ONE | www.plosone.org 16 August 2009 | Volume 4 | Issue 8 | e6623