Witelson S F
Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada.
Brain. 1989 Jun;112 ( Pt 3):799-835. doi: 10.1093/brain/112.3.799.
The midsagittal area of the corpus callosum was measured in its entirety and in seven subdivisions in a sample of 50 brains consecutively obtained from autopsies of individuals who had neuropsychological testing before death. A 12-item test of hand preference was used as an index of the pattern of interhemispheric functional asymmetry. Callosal size was analysed for two factors: hand preference, classified as consistent-right-hand preference (CRH) versus non consistent-right-hand preference, and sex. The group of nCRH (n = 18) was found to have a larger overall callosal area, with the greatest difference occurring in the posterior body segments, especially the isthmus. The isthmus probably includes interhemispheric fibres from posterior parietal and superior temporal cortex which involves cortical regions related to functional asymmetry. The results of variation in callosal morphology are discussed as part of a possible substrate of functional asymmetry and due to variation in axonal elimination in early brain development. Sex differences were found in several aspects of callosal anatomy. (1) The difference between hand groups in the posterior body occurred in interaction with sex:handedness was a factor in callosal size in males (n = 15), but not in females (n = 35). This result is consistent with the general hypothesis of females having less clear lateralization than males. (2) Females did not have a larger overall callosum or a larger splenium, either in absolute size or size proportional to brain weight. The latter measure was considered since callosal area correlated with cerebrum weight (r = 0.48). In contrast, female of both hand groups were found to have a larger proportional isthmus compared to CRH males. (3) Of all callosal regions, only the genu and a part of the anterior body were found to be larger in absolute size in males than females. (4) Callosal size decreased with chronological age in males, but not in females.
在50个连续取自生前接受过神经心理学测试个体尸检的大脑样本中，对胼胝体的整个矢状面区域及其七个亚区进行了测量。使用一项12项的利手测试作为半球间功能不对称模式的指标。分析胼胝体大小的两个因素：利手，分为持续右利手（CRH）与非持续右利手，以及性别。发现非CRH组（n = 18）的胼胝体总面积更大，最大差异出现在胼胝体后段，尤其是峡部。峡部可能包含来自顶叶后部和颞上叶皮质的半球间纤维，这些区域涉及与功能不对称相关的皮质区域。胼胝体形态变化的结果作为功能不对称的可能基础的一部分进行了讨论，这是由于早期大脑发育中轴突消除的变化所致。在胼胝体解剖学的几个方面发现了性别差异。（1）胼胝体后段的利手组差异与性别相互作用：利手是男性（n = 15）胼胝体大小的一个因素，但不是女性（n = 35）的因素。这一结果与女性比男性的偏侧化不太明显的一般假设一致。（2）女性无论是绝对大小还是与脑重成比例的大小，都没有更大的整体胼胝体或更大的压部。考虑了后一种测量方法，因为胼胝体面积与脑重相关（r = 0.48）。相比之下，发现两个利手组的女性与CRH男性相比，峡部比例更大。（3）在所有胼胝体区域中，仅发现男性的膝部和前体的一部分在绝对大小上比女性大。（4）男性的胼胝体大小随实际年龄下降，但女性没有。
