Optical analysis of functional formation of the brainstem neural circuit and its r egulation by the depolarization wave

在发育中的中枢神经系统（CNS）中，未成熟的神经网络产生广泛的自发相关活动。利用电压敏感染料的光学成像技术，我们在大鼠和鸡胚中发现了一个广泛传播的波，我们称之为去极化波。去极化波的一个新奇在于它在包括脑干、脊髓、小脑和部分大脑在内的广泛的中枢神经系统区域上传播。另一个突出的特点是，它是非特异性触发的各种类型的感觉输入以及内源性自发活动。这些配置文件表明，波可能不是作为一个简单的调节器的特定神经元回路的形成，但可能发挥更全面的作用，在中枢神经系统的发展。去极化波由多种神经递质和缝隙连接介导，且随着发育，优势递质由乙酰胆碱转变为谷氨酸。对去极化波起源的监测表明，该波最初起源于靠近奥贝的上颈髓/下延髓，并在后期由多个区域产生。该网络可能作为一个自我分配系统，维持发育中CNS的相关活性。

In the developing central nervous system (CNS), immature neural networks generate spontaneous correlated activity in a wide range. Using the optical imaging technique with voltage-sensitive dyes, we found a widely-spreading wave in the rat and chick embryos, which was termed the depolarization wave. One novelty of the depolarization wave was that it traveled over a wide region of the CNS including the brainstem, spinal cord, cerebellum, and part of the cerebrum. Another outstanding feature was that it was non-specifically triggered by various types of sensory inputs as well as endogenous spontaneous activity. These profiles suggest that the wave may not serve as a simple regulator of specific neuronal circuit formation, but might play a more global role in CNS development. The depolarization wave was mediated by multiple neurotransmitters and gap junctions, and the dominant transmitter switched from acetylcholine to glutamate with development. Surveillance of the origin of the depolarization wave showed that the wave initially originated in the upper cervical cord/lower medulla near the obex and was generated by multiple regions at the later stages. This network possibly works as a self-distribution system that maintains the correlated activity in the developing CNS.