U.S. researchers have determined the influence of sex and handedness on the brain is similar in capuchin monkeys and in humans.
Hiram College scientists said their research shows capuchin monkeys -- known for their manual dexterity, complex social behavior and cognitive abilities -- display, as do humans, a fundamental sex difference in the organization of the brain, specifically in the corpus callosum -- the region connecting the two cerebral lobes.
In the study led by Professor Kimberley Phillips and Alayna Lilak, 13 adult capuchins underwent magnetic resonance imaging to determine the size of their corpus callosum.
The monkeys were later given a task to determine hand preference. The results led the researchers to conclude that, as in humans, male capuchins have a smaller relative size of the corpus callosum than females, and right-handed individuals have a smaller relative size of the corpus callosum than left-handed individuals.
Phillips hypothesize the findings are related to hemispheric specialization for complex foraging tasks that require the integration of motor actions and visuospatial information.
The study, which included Chet Sherwood of George Washington University, appears in the online journal PLoS One and is available at http://www.plosone.org/doi/pone.0000792.