Abstract # 6281 Poster # 199:

Scheduled for Friday, June 19, 2015 06:00 PM-08:00 PM: (Cascade AJBCD) Poster Presentation


INTERHEMISPHERIC CONNECTIVITY IN TWO SPECIES OF PRIMATES: SPIDER MONKEYS (ATELES GEOFFROYI) AND STUMPTAIL MACAQUES (MACACA ARCTOIDES).

D. Platas-Neri1, S. Hidalgo-Tobón2,3, F. Chico2 and J. Muñoz-Delgadoe4
1Universidad Autónoma del Estado de Morelos, Campus Sur, Av. 18 de Marzo No. 617 , Jojutla, Morelos 62900, USA, 2Hospital Infantil de México Federico Gómez, México, D. F., 3Universidad Autónoma Metropolitana, Iztapalapa, México D.F., 4, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, México, D.F
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     The objective of this research was to analyze the ratio of corpus callosum surface area (CCSA) to brain volume (BV) of the spider monkey (A. geoffroyi) and stumptail macaques (M. arctoides). In an evolutionary scope, studies have shown that increased brain size is associated with reduced interhemispheric connections; the CCSA should be relatively smaller in primates with the largest brains, at the same time, this should correlate with hemispheric dominance and lateralization phenomenon resulting in increasingly independent hemispheres. It has also been suggested that the CCSA is a measure of the degree of connectivity between the left and right hemispheres of the brain. To test this hypothesis, we used MRI scans (3T Achieva-Phillips scanner) from 14 subjects. All measurements were made with the Osirix analysis software program. CCSA was identified using a biplanar method. Measurements were obtained by manual trace and compared by different observers (n=6) using Cronbach's alpha reliability index with a significance of 0.99. Student’s t test was used to compare the mean ratio of corpus callosum (t=0.11, p<0.05). We confirm the tendency that Rilling and Insel (1999), report: the mean ratio of corpus callosum for Cebidae such as spider monkeys is 1.10 and for Cercopitecida such as stump tail macaques is 0.97. These ratios and phylogeny data suggest that interhemispheric connections via corpus callosum have a reduction tendency in large primate brains.