Cerebral Anatomy of the Spider Monkey Ateles Geoffroyi Studied Using Magnetic Resonance Imaging. First Report: a Comparative Study with the Human Brain Homo Sapiens

The objective of the present qualitative studywas to analyze the morphological aspects of theinner cerebral anatomy of two species of primates,using magnetic resonance images (MRI):spider monkey (A. geoffroyi) and human (H.sapiens), on the basis of a comparative study ofthe cerebral structures of the two species, focusingupon the brain of the spider monkey and,primarily, its limbic system. In spite of beingan endemic Western hemisphere species, a factwhich is by its own right interesting for researchdue to this animal’s social organization and motorfunctions, the spider monkey (A. geoffroyi)has hardly been studied in regard to its neuroanatomy.MRI was carried out, in one spidermonkey, employing a General Electric Signa1.5 T scanner. This investigation was carried inaccordance to international regulations for theprotection of animals in captivity, taking intoaccount all protective means utilized in experimentalhandling, and not leaving behind any residualeffects, either physiological or behavioral.From a qualitative point of view, the brains ofthe spider monkey and the human were found to have similar structures. In reference to shape,the most similar structures were found in thelimbic system; proportionally, however, cervical curvature, amygdala, hippocampus, anteriorcommissure and the colliculi, were larger in thespider monkey than in the human