Abstract # 171:

Scheduled for Sunday, September 14, 2014 07:00 PM-09:00 PM: Session 22 (Decatur B) Poster Presentation


CHIMPANZEES’ MORE EFFICIENT HAND DURING A TOOL-USE TASK PREDICTS NEUROANATOMICAL ASYMMETRIES IN BROCA’S AND MOTOR HAND AREAS

S. M. Pope1, M. C. Mareno2, L. A. Reamer2, S. J. Schapiro2 and W. D. Hopkins1,3
1Georgia State University, Neuroscience Institute, 880 Petit Science Center, Atlanta, GA 30303, USA, 2M.D. Anderson Cancer Research Center, 3Yerkes National Primate Research Center
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     Here, we examined whether hand preferences or performance asymmetries in tool use are associated with neuroanatomical asymmetries in the motor hand area of the precentral gyrus (MHA) and Broca’s area homolog (IFG) in chimpanzees (Pan Troglodytes). Brain and behavioral data were examined in 176 chimpanzees including 69 males and 107 females (Mean age = 26.31 years, s.d. = 10.55). Hand preference and skill were measured on a tool-use task designed to simulate termite fishing. Data were collected on 50 responses per subject. Hand preference was calculated from the frequency of hand use and hand efficiency from the latency for tool insertions. Behavioral data was compared to left-right differences for asymmetry quotients (AQ) in the volume of the MHA and IFG, respectively. Volume measurements were attained from region of interest (ROI) analysis of MRI volumes. There were no significant associations between IFG and MHA asymmetries and the hand preference measure. However, hand efficiency was significantly associated with both IFG and MHA AQ scores [F (1,171)=8.34; p=0.004]. Chimpanzees that performed better with their right hand showed greater leftward lateralization (AQ = -.104) than individuals that performed better with their left hand (AQ = .078). These results are consistent with the view that Broca’s area plays a role in praxic functions and may have served as a preadaptation for the emergence of other motor functions, such as speech.