Abstract # 12:

Scheduled for Thursday, June 19, 2008 09:45 AM-09:55 AM: Session 2 (Meeting Room 1GHI) Oral Presentation

The Use of Voxel-Based Morphology to Assess Asymmetries in the Chimpanzee Brain: A Novel Approach to Comparative Studies in Cerebral Organization

W. Hopkins1,2, J. P. Taglialatela1 and A. Meguerditchian1,3
1Yerkes National Primate Res. Ctr., Division of Psychobiology, Emory Univ., 954 Gatewood Road, Atlanta, GA 30329, USA, 2Department of Psychology, Agnes Scott College, 141 E. College Avenue, Decatur, Georgia, 3Dept. of Psych., Research Center in Psychology of Cognition, Language & Emotion, University of Provence, 29, Av. Robert Schuman, 13621 Aix-en-Provence, France
     Whether or not nonhuman primates exhibit neuroanatomical asymmetries remains a topic of intense scientific debate. One serious challenge to comparative studies of brain asymmetries in primates is the variation in sulci used to define specific regions of interest between species. A potential alternative means to assess asymmetries and other aspects of cerebral organization is voxel-based morphometry (VBM). In this study, we report the first evidence of population-level asymmetries in chimpanzees using voxel-based morphometry. MRI scans were collected in a sample of 30 chimpanzees including 12 males and 18 females, and the resulting images were segmented into gray matter, white matter and CSF. Images were then co-registered to a template and the normally oriented brains were flipped on the left-right axis to create mirror volumes. In total, significant asymmetries were found in 23 regions [t-tests, a=0.001] including several that have been described previously in apes using traditional region-of-interest approaches. Sex and handedness had small to moderate effects on brain asymmetries [t-tests, a=0.05]. The results from this VBM analysis support previous reports of hemispheric lateralization in great apes and reinforce the view that asymmetries in the central nervous system are not uniquely human. Furthermore, the results suggest that VBM offers a very powerful alternative means of investigating aspects of cerebral organization in different primate species.