Abstract # 2516 Event # 211:

Scheduled for Monday, September 21, 2009 11:15 AM-11:25 AM: Session 22 (Mission Bay Ballroom AB) Oral Presentation


PREY CAPTURE EFFICIENCY IN CAPUCHIN MONKEYS (CEBUS APELLA) IS INFLUENCED BY SEX AND CORPUS CALLOSUM MORPHOLOGY

K. . Hellner-Burris, C. A. Sobieski, V. R. Gilbert and K. A. Phillips
Hiram College, Neuroscience Program, Hiram, Ohio 44234, USA
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The corpus callosum (CC) is the major white matter tract connecting the cerebral hemispheres and provides for interhemispheric integration of sensory, motor and cognitive information. The midsagittal area of the CC is frequently used as a marker of hemispheric lateralization, connectivity and function. Morphological sex differences in total CC:brain ratio are found in capuchins, with males having smaller ratios than females. Sex differences are also seen in CC subdivisions involved in motor processing (anterior midbody) and spatial ability (splenium), with males again having smaller regions. While the functional significance of this is unclear, we hypothesized that it is related to efficiency in complex visuospatial tasks such as prey capture. Here we explored prey capture efficiency using a fishing task, hypothesizing that males would be more efficient. Four adult female and three adult/young adult male capuchins were tested across 30 trials. For each trial, we recorded the number of attempts, the hand used in each attempt, and the time for prey capture. Males were significantly faster [t-test, p=0.03] and more successful [t-test, p=0.05] at capturing prey. Additionally, males had smaller total CC:brain ratios [t-test, p=0.01] and smaller splenia [t-test, p=0.07]. Males displayed a significant unimanual preference [t-test, p=0.01], while females displayed no significant hand preference. Males also displayed a left hand bias. These results suggest a relationship between the CC:brain ratio and prey capture efficiency.