O'Malley D M, Kao Y H, Fetcho J R
Department of Neurobiology and Behavior, State University of New York at Stony Brook 11794-5230, USA.
Neuron. 1996 Dec;17(6):1145-55. doi: 10.1016/s0896-6273(00)80246-9.
Although vertebrate hindbrains are segmented structures, the functional significance of the segmentation is unknown. In zebrafish, the hindbrain segments contain serially repeated classes of individually identifiable neurons. We took advantage of the transparency of larval zebrafish and used confocal calcium imaging in the intact fish to study the activity of one set of individually identified, serially homologous reticulospinal cells (the Mauthner cell, MID2cm, and MID3cm) during behavior. Behavioral studies predicted that differential activity in this set of serially homologous neurons might serve to control the directionality of the escape behavior that fish use to avoid predators. We found that the serially homologous cells are indeed activated during escapes and that the combination of cells activated depends upon the location of the sensory stimulus used to elicit the escape. The patterns of activation we observed were exactly those predicted by behavioral studies. The data suggest that duplication of ancestral hindbrain segments, and subsequent functional diversification, resulted in sets of related neurons whose activity patterns create behavioral variability.
尽管脊椎动物的后脑是分段结构，但其分段的功能意义尚不清楚。在斑马鱼中，后脑节段包含一系列可单独识别的神经元类别。我们利用斑马鱼幼体的透明性，在完整的鱼中使用共聚焦钙成像技术，研究了一组单独识别的、系列同源的网状脊髓细胞（Mauthner细胞、MID2cm和MID3cm）在行为过程中的活动。行为学研究预测，这组系列同源神经元的差异活动可能有助于控制鱼类用于躲避捕食者的逃避行为的方向性。我们发现，系列同源细胞在逃避过程中确实被激活，并且被激活的细胞组合取决于用于引发逃避的感觉刺激的位置。我们观察到的激活模式与行为学研究所预测的完全一致。数据表明，祖先后脑节段的复制以及随后的功能多样化，导致了一组相关神经元的产生，其活动模式产生了行为变异性。
