Ohte Naoto, Kimura Takayuki, Sekine Rintaro, Yoshizawa Shoko, Furusho Yuta, Sato Daisuke, Nishiyama Chihiro, Hanashima Carina
Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, 162-8480, Tokyo, Japan.
Department of Integrative Bioscience and Biomedical Engineering, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, 162-8480, Tokyo, Japan.
Cereb Cortex. 2025 Feb 5;35(2). doi: 10.1093/cercor/bhae491.
The cerebral cortex consists of hierarchically organized areas interconnected by reciprocal axonal projections. However, the coordination of neurogenesis to optimize neuronal production and wiring between distinct cortical areas remains largely unexplored. The somatosensory cortex plays a crucial role in processing tactile information, with inputs from peripheral sensory receptors relayed through the thalamus to the primary and secondary somatosensory areas. To investigate the dynamics of neurogenesis in cortical circuit formation, we employed temporal genetic fate mapping of glutamatergic neuron cohorts across the somatosensory cortices. Our analysis revealed that neuronal production in the secondary somatosensory cortex (S2) precedes that of the primary somatosensory cortex (S1) from the deep-layer neuron production period and terminates earlier. We further revealed a progressive decline in upper-layer neuron output in S2, attributed to the attenuation of the apical ventricular surface, resulting in a reduced number of upper-layer neurons within S2. These findings support the existence of a protomap mechanism governing the area-specific assembly of primary and secondary areas in the developing neocortex.
大脑皮层由通过相互的轴突投射相互连接的分层组织区域组成。然而，神经发生的协调以优化不同皮层区域之间的神经元产生和连接在很大程度上仍未得到探索。体感皮层在处理触觉信息方面起着至关重要的作用，来自外周感觉受体的输入通过丘脑传递到初级和次级体感区域。为了研究神经发生在皮层回路形成中的动态变化，我们对整个体感皮层的谷氨酸能神经元群体进行了时间性遗传命运图谱分析。我们的分析表明，从深层神经元产生期开始，次级体感皮层（S2）的神经元产生先于初级体感皮层（S1），并且更早终止。我们进一步发现S2上层神经元输出逐渐下降，这归因于顶端脑室表面的衰减，导致S2内上层神经元数量减少。这些发现支持了一种原图谱机制的存在，该机制控制着发育中的新皮层中初级和次级区域的区域特异性组装。
