Laboratory of Neuro Imaging, Department of Neurology, University of California, Los Angeles, School of Medicine, Los Angeles, California 90095-7334, USA.
J Neurosci. 2010 Aug 18;30(33):10985-90. doi: 10.1523/JNEUROSCI.5122-09.2010.
The corpus callosum changes structurally throughout life, but most dramatically during childhood and adolescence. Even so, existing studies of callosal development tend to use parcellation schemes that may not capture the complex spatial profile of anatomical changes. Thus, more detailed mapping of callosal growth processes is desirable to create a normative reference. This will help to relate and interpret other structural, functional, and behavioral measurements, both from healthy subjects and pediatric patients. We applied computational surface-based mesh-modeling methods to analyze callosal morphology at extremely high spatial resolution. We mapped callosal development and explored sex differences in a large and well matched sample of healthy children and adolescents (n = 190) aged 5-18 years. Except for the rostrum in females, callosal thickness increased across the whole surface, with sex- and region-specific rates of growth, and at times shrinkage. The temporally distinct changes in callosal thickness are likely to be a consequence of varying degrees of axonal myelination, redirection, and pruning. Alternating phases of callosal growth and shrinkage may reflect a permanent adjustment and fine-tuning of fibers connecting homologous cortical areas during childhood and adolescence. Our findings emphasize the importance of taking into account sex differences in future studies, as existing developmental effects might remain disguised (or biased toward the effect of the dominant sex in unbalanced statistical designs) when pooling male and female samples.
胼胝体在整个生命过程中结构都会发生变化，但在儿童和青少年时期最为显著。即便如此，现有的胼胝体发育研究往往采用可能无法捕捉到解剖结构复杂空间分布的分割方案。因此，更详细地绘制胼胝体生长过程是很有必要的，以便建立一个规范的参考。这将有助于将其他结构、功能和行为测量结果与健康受试者和儿科患者的测量结果联系起来并进行解释。我们应用基于计算表面的网格模型方法，以极高的空间分辨率分析胼胝体形态。我们对胼胝体的发育进行了研究，并在一个由 190 名年龄在 5 至 18 岁的健康儿童和青少年组成的大样本中，探索了性别差异。除了女性的嘴部，整个胼胝体表面的厚度都在增加，存在性别和区域特异性的生长速度，有时也会收缩。胼胝体厚度的时间上的差异可能是轴突髓鞘形成、重定向和修剪程度不同的结果。胼胝体生长和收缩的交替阶段可能反映了在儿童和青少年时期，连接同源皮质区域的纤维不断进行永久性的调整和微调。我们的发现强调了在未来研究中考虑性别的重要性，因为当合并男性和女性样本时，现有的发育影响可能仍然被掩盖（或偏向于不平衡统计设计中占主导地位的性别）。
