title: Correlations between hand preference and cortical thickness in the secondary somatosensory (SII) cortex of the common marmoset, Callithrix jacchus.
abstract: Cortical asymmetries are well established in humans for language and motor regions and correlate with handedness. Here the authors investigate structural differences in the hemispheres of left- and right-handed common marmosets using surface photography and histology. The hand preferences of 11 marmosets were assessed over their adult life span using a simple reaching task. A significant correlation was found between the length of the right lateral sulcus/brain weight and the % right-hand preference (r = .86, p = .001). Cortical thickness on the superior bank of the right lateral sulcus posteriorly was also positively correlated with % right-hand preference (r = .69, p = .025). Comparison of this site with previously published functional maps of the marmoset cortex show this area corresponds to SII, a region involved in tactile processing and somatosensory discriminations. It is suggested that the correlation between SII thickness and right-hand preference would be consistent with the fact that right-handed marmosets are more proactive than left-handers in exploring novel objects by touch. Enlargement of a cortical area involved tactile discriminations could be a precursor to the evolution of right-handedness as a population bias.
authors.affiliation: Neural Injury Research Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, USA. c.gorrie@unsw.edu.au
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Gorrie
authors.forename: Phil M E
authors.initials: PM
authors.lastname: Waite
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Rogers
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001931:Brain Mapping; D002144:Callithrix / Q000033:anatomy & histology* / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D007839:Functional Laterality; D009434:Neural Pathways; D011597:Psychomotor Performance / Q000502:physiology*; D013003:Somatosensory Cortex / Q000033:anatomy & histology*; D034941:Upper Extremity