Chimpanzee (Pan troglodytes) Precentral Corticospinal System Asymmetry and Handedness: A Diffusion Magnetic Resonance Imaging Study

• Type of Material: Article
• Authors: Longchuan Li, Emory University; Todd M Preuss, Emory University; James K Rilling, Emory University; Bill Hopkins, Emory University; Matthew F. Glasser, Emory University; Bhargav Kumar, Emory University; Roger Nana, Emory University; Xiaodong Zhang, Emory University; Xiaoping P Hu, Emory University
• Language: English
• Date: 2010-09-21
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © Li et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0012886
• Title of Journal or Parent Work: PLoS ONE
• Volume: 5
• Issue: 9
• Grant/Funding Information: This work was kindly supported by the National Institutes of Health (http://www.nih.gov/; 5P01 AG026423-03, NS-42867 and HD-56232) and Yerkes National Primate Research Center (http://www.yerkes.emory.edu/; RR-00165).; The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
• Research Categories: Chemistry, Biochemistry; Biology, Animal Physiology

Abstract

Background Most humans are right handed, and most humans exhibit left-right asymmetries of the precentral corticospinal system. Recent studies indicate that chimpanzees also show a population-level right-handed bias, although it is less strong than in humans. Methodology/Principal Findings We used in vivo diffusion-weighted and T1-weighted magnetic resonance imaging (MRI) to study the relationship between the corticospinal tract (CST) and handedness in 36 adult female chimpanzees. Chimpanzees exhibited a hemispheric bias in fractional anisotropy (FA, left>right) and mean diffusivity (MD, right>left) of the CST, and the left CST was centered more posteriorly than the right. Handedness correlated with central sulcus depth, but not with FA or MD. Conclusions/Significance These anatomical results are qualitatively similar to those reported in humans, despite the differences in handedness. The existence of a left>right FA, right>left MD bias in the corticospinal tract that does not correlate with handedness, a result also reported in some human studies, suggests that at least some of the structural asymmetries of the corticospinal system are not exclusively related to laterality of hand preference.