Nuclear Architecture in the Medulla Oblongata of the Adult African Giant Pouched Rat (Cricetomys gambianus, Waterhouse - 1840)

the architecture of cranial and non-cranial nerve nuclei in the medulla oblongata of the african giant pouched rat was studied by means of light microscopy. serial sections of the medulla oblongata, in coronal and saggital planes, were stained with the cresyl fast violet and silver stains, respectively. sections in the saggital plane were used as a guide, while coronal sections were used to identify the nuclei in the rostrocaudal extent of the medulla oblongata. with the obex serving as the landmark, nuclei rostral and caudal to the obex were delineated. cranial nerve nuclei whose architecture were defined were the motor nucleus of hypoglossal nerve, motor nucleus of vagus nerve, cochlear nucleus, vestibular nucleus and nucleus ambiguus, while non-cranial nerve nuclei identified were the olivary nucleus, solitary tract nucleus, gracile nucleus, cuneate nucleus, spinal nucleus of trigeminal nerve, motor nucleus of corpus trapezoideum, lateral nucleus of reticular formation and gigantocellular nucleus. the olivary nucleus was the most prominent nucleus, while the solitary tract nucleus was faint, and thus, less developed. the rostrocaudal extent of the solitary tract nucleus, olivary nucleus and motor nucleus of hypoglossal nerve were 3.81 mm, 2.36 mm and 3.50 mm in length, respectively. the prominent olivary nucleus, pyramidal tract and vestibular nucleus are indicative of a good motor coordination and balance, while the poorly developed solitary tract nucleus points to less efficient autonomic functions in this rodent. the present study will serve as a lead for future neuro-behavioural studies necessary for an effective domestication and adaptation of the african giant pouched rat.