Luders E, Narr K L, Zaidel E, Thompson P M, Jancke L, Toga A W
Laboratory of Neuro Imaging, Department of Neurology, Brain Mapping Division, UCLA School of Medicine, 710 Westwood Plaza, 4238 Reed, Los Angeles, CA 90095-1769, USA.
Cereb Cortex. 2006 Mar;16(3):346-54. doi: 10.1093/cercor/bhi112. Epub 2005 May 18.
Significant relationships have been reported between midsagittal areas of the corpus callosum and the degree of interhemispheric transfer, functional lateralization and structural brain asymmetries. No study, however, has examined whether parasagittal callosal asymmetries (i.e. those close to the midline of the brain), which may be of specific functional consequence, are present in the human brain. Thus, we applied magnetic resonance imaging and novel computational surface-based methods to encode hemispheric differences in callosal thickness at a very high resolution. Discrete callosal areas were also compared between the hemispheres. Furthermore, acknowledging the frequently reported sex differences in callosal morphology, parasagittal callosal asymmetries were examined within each gender. Results showed significant rightward asymmetries of callosal thickness predominantly in the anterior body and anterior third of the callosum, suggesting a more diffuse functional organization of callosal projections in the right hemisphere. Asymmetries were increased in men, supporting the assumption of a sexually dimorphic organization of male and female brains that involves hemispheric relations and is reflected in the organization and distribution of callosal fibers.
据报道，胼胝体矢状中部区域与半球间传递程度、功能侧化及大脑结构不对称之间存在显著关联。然而，尚无研究探讨矢旁胼胝体不对称性（即靠近脑中线的那些不对称性）在人类大脑中是否存在，而这种不对称性可能具有特定的功能影响。因此，我们应用磁共振成像和基于计算表面的新方法，以非常高的分辨率编码胼胝体厚度的半球差异。还比较了半球之间离散的胼胝体区域。此外，鉴于胼胝体形态学中经常报道的性别差异，我们在每个性别中检查了矢旁胼胝体不对称性。结果显示，胼胝体厚度主要在胼胝体的前体和前三分之一处存在显著的向右不对称，这表明右半球胼胝体投射的功能组织更为分散。男性的不对称性增加，支持了关于男性和女性大脑存在性二态组织的假设，这种组织涉及半球关系，并反映在胼胝体纤维的组织和分布中。
