Hemispheric asymmetry and corpus callosum morphometry: a magnetic resonance imaging study

Previous post-mortem studies (Aboitiz, F.. Scheibel, A.B., Fisher, R.S., Za idel, E., 1992. Brain Res. 598, 154-161 and Aboitiz, F., Scheibel, A.B., Za idel, E.: 1992. Brain 115, 1521-1541) have shown an inverse association bet ween asymmetry in perisylvian areas and the size of a specific segment, the isthmus, of the corpus callosum (CC) in males. The purpose of this work wa s to study in vivo the association between hemispheric asymmetry and the to tal size of the CC in 35 right-handed subjects (16 males, 19 females, mean age 24.9 +/- 3.9). An MRI scan was performed for each subject. The area of the right (RH) and left (LH) hemispheres were measured from images in the s agittal plane and the area of the CC from images in the mid-sagittal plane. The index of hemispheric asymmetry was \(LH - RH)/[(LH + RH)/2]\. There wa s a negative correlation between the absolute value of hemispheric asymmetr y and the size of the CC in males (r = - 0.55, P = 0.03) but not in females (r = - 0.20, P = 0.42). These findings, like those of Aboitiz et al. (Aboi tiz, F., Scheibel, A.B., Zaidel, E., 1992. Brain 115, 1521-1541), suggest a sex-dependent decrease in interhemispheric connectivity with increasing he mispheric asymmetry. (C) 2000 Published by Elsevier Science Ireland Ltd. Al l rights reserved.