Effects of handedness and sex on the morphology of the corpus callosum: a study with brain magnetic resonance imaging.
In view of conflicting data in the existing literature, we examined 53 normal subjects using a handedness questionnaire and callosal area measurements obtained from midsagittal MRI images. The callosum was found to be significantly larger in nonconsistent right-handers (NCRH), especially in its anterior half and especially for males. A significant hand x sex interaction, favoring consistent right-handed (CRH) females, was also found for the posterior midbody, a region known to house interhemispheric fibers connecting the right and left posterior association cortices. These results (1) confirm Witelson's (1985) first findings on postmortem specimens; (2) validate a dichotomy between CRH and NCRH rather than simply considering the writing hand, as was the case in most other similar studies; and (3) suggest that at least two different sex-related--probably hormonal--factors may be acting during the callosal development, one explaining the larger anterior half in NCRH males and the other the larger posterior midbody in CRH females.
Habib
M
M
Neurological Clinic, C.H.U. Timone, Marseilles, France.
Gayraud
D
D
Oliva
A
A
Regis
J
J
Salamon
G
G
Khalil
R
R
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003337:Corpus Callosum / Q000033:anatomy & histology* / Q000502:physiology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D011795:Surveys and Questionnaires