Fig. (2). Inferior olivary nucleus A) Normal structure in a control case (female, aged 2 months). Arrows point to accessory subnuclei (dorsal and medial, respectively).B) Hypoplasia in a case of SIDS (male, aged 4 months) with lack of both the medial and dorsal accessory nuclei. Klüver-Barrera stain. Magnification: 4x.