Department of Behavioral Neuroscience, Northeastern University, Boston, MA 02115, USA.
Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
Cereb Cortex. 2017 Dec 1;27(12):5683-5695. doi: 10.1093/cercor/bhw339.
The thalamus plays an important role in signal relays in the brain, with thalamocortical (TC) neuronal pathways linked to various sensory/cognitive functions. In this study, we aimed to see fetal and postnatal development of the thalamus including neuronal migration to the thalamus and the emergence/maturation of the TC pathways. Pathways from/to the thalami of human postmortem fetuses and in vivo subjects ranging from newborns to adults with no neurological histories were studied using high angular resolution diffusion MR imaging (HARDI) tractography. Pathways likely linked to neuronal migration from the ventricular zone and ganglionic eminence (GE) to the thalami were both successfully detected. Between the ventricular zone and thalami, more tractography pathways were found in anterior compared with posterior regions, which was well in agreement with postnatal observations that the anterior TC segment had more tract count and volume than the posterior segment. Three different pathways likely linked to neuronal migration from the GE to the thalami were detected. No hemispheric asymmetry of the TC pathways was quantitatively observed during development. These results suggest that HARDI tractography is useful to identify multiple differential neuronal migration pathways in human brains, and regional differences in brain development in fetal ages persisted in postnatal development.
丘脑在大脑信号转导中发挥着重要作用，丘脑皮质（TC）神经元通路与各种感觉/认知功能有关。在这项研究中，我们旨在观察包括神经元迁移到丘脑和 TC 通路的出现/成熟在内的胎儿和产后丘脑发育。使用高角度分辨率扩散磁共振成像（HARDI）示踪技术研究了来自尸检胎儿和体内受试者（从新生儿到无神经病史的成年人）的丘脑的通路。成功检测到可能与脑室区和神经节隆起（GE）向丘脑迁移的神经元相关的两条通路。在脑室区和丘脑之间，前区比后区发现了更多的示踪路径，这与产后观察结果一致，即前 TC 段的示踪计数和体积大于后段。检测到三条可能与 GE 向丘脑迁移的神经元相关的不同通路。在发育过程中，没有观察到 TC 通路的半球性不对称。这些结果表明，HARDI 示踪技术可用于识别人类大脑中的多种不同的神经元迁移途径，并且在胎儿期，大脑发育的区域差异在后脑发育中持续存在。
