A. In the cat, the poorly-developed neural sheet curves. B. In the macaque, the moderately developed neural sheet curves. C. In the human, the extremely well-developed neural sheet is completely rolled. The human NB is defined as the dorsomedial part of the red nucleus and it projects to the vl of PO via the medial part of the CTT. A strong stream of these well-developed CTT fibers separates the NB from ND. The gray color indicates a “still uncertain” projection. CTT–central tegmental tract, dmpNr–dorsomedial part of parvicellular red nucleus, lb–lateral bend, MAO–medial accessory olive, MTT–medial tegmental tract, NB–nucleus accessorius medialis of Bechterew, ND–nucleus of Darkschewitsch, PO–principal olive, vl–ventral lamella, vlpNr–ventorlateral part of parvicellular red nucleus.