Sexual dimorphism in the whole brain and brainstem morphometry in the African giant pouched rat (Cricetomys gambianus, Waterhouse 1840)

The study was conducted to evaluate the sexual dimorphism in the morphometric parameters of the whole brain and the brainstem in adult captive African giant pouched rats. Twenty-nine brain samples, comprising 15 females and 14 males, were utilized. Following brain extraction by standard procedures, the mean values of the weights, lengths, diameters, and volumes of the intact brains and the brainstem structures were compared in male and female rats using quantitative analytical statistical methods. The absolute brain weight obtained in the male was significantly higher (p < 0.01) than that of the female while the relative brain weight obtained in the female (0.636 +/- 0.049%) was higher than that of the male rats (0.564 +/- 0.032%), although the difference in the values was not statistically significant (p > 0.05). The lengths of the brain and myelencephalon, as well as the weights of the myelencephalon and mesencephalon, did not differ between the two sexes (p > 0.05). The weights and lengths of the pons did not differ between the two sexes (p > 0.05). There was a significant difference (p < 0.05) in the pyramidal length and a highly significant difference (p < 0.01) in the pyramidal width between the two sexes, with the male rats having higher values. This pioneering sexual dimorphic brain morphometry provides information for further research.