Neuroscience: unveiling the brain of Saimiri collinsi (Squirrel Monkey)

Behavioral intelligence among non-human primates is a somewhat puzzling area to study, since it is closely linked to the morphology of the central nervous system. However, this morphology is still unknown to science in the case of Saimiri collinsi. As a means of assisting future studies on the social behavior of this species, we analyzed the brains of six adult females from the National Primate Center / Pará, which were sent to the Animal Morphological Research Laboratory at the Federal Rural University of Amazônia after death by natural causes. The animals were fixed in formaldehyde solution (10%) and dissected. The brains were covered externally by the dura mater, with long cerebral hemispheres, although there was a complete absence of gyri. The internal structures which form a part of the telencephalon, diencephalon, midbrain, hindbrain and myelencephalon were identified, with the exception of the mammillary bodies. This condition, when linked to the lissencephaly found in these individuals raises questions about the real learning abilities of this species.