Abstract # 35:

Scheduled for Thursday, June 21, 2007 02:30 PM-02:45 PM: Session 6 (North Main Hall F/G) Oral Presentation

Normative Data of the Chimpanzee Brain as Revealed by Magnetic Resonance Imaging: Age and Sex Effects

W. Hopkins1,2, J. P. Taglialatela1,2 and C. Cantalupo3
1Yerkes National Primate Research Center, Division of Psychobiology, Atlanta 30305, USA, 2Department of Psychology, Agnes Scott College, 3Department of Psychology, Clemson University
     Although general normative data are available on brain size in chimpanzees (Pan troglodytes), most of the extant data come from post-mortem studies. These studies are limited by shrinkage of brain tissue due to the fixative as well as relatively small sample sizes, which limits analysis evaluating the influence of age and sex on neuroanatomy. Here we report normative data on a number of brains regions of interest (ROI) measured from magnetic resonance images in a sample of 83 captive chimpanzees. ROI’s included brain volume, cerebellum, hippocampus, amygdala, corpus callosum, and striatum (putamen, caudate). Additional data on variation in gyrification and cerebral white matter are also reported. Overall, after adjusting for multiple comparisons, no sex differences were found for any brain regions. Age differences were found in relative white matter concentrations [r(81)=-0.32, p<0.05], and relative volumes of the striatum [r(81)=-0.31, p<0.05] and cerebellum [r(81)=-0.37, p<0.05], with smaller values in older apes. Lastly, left-right differences were found in the shape of the brain with apes showing a significant right-frontal, left-occipital torque [t(82)=3.39, p<0.001]. Overall, the results revealed no sex differences in neuroanatomy in chimpanzees and selective age-related volumetric loss in brain regions associated with motor functions (cerebellum, striatum).