Strausfeld N J, Gronenberg W
Arizona Research Laboratories, University of Arizona, Tucson 85721.
J Comp Neurol. 1990 Dec 22;302(4):954-72. doi: 10.1002/cne.903020419.
In dipterous insects, a volume of behavioral and electrophysiological studies promote the contention that three wide-field motion-sensitive tangential neurons provide a necessary and sufficient input to specific channels that drive the torque motor during flight. The present studies describe the results of neuroanatomical investigations of the relationships between motion-sensitive neuropil in the fly optic lobes and descending neurons that arise from a restricted area of the brain and supply segmental neck and flight motor neuropil. The present observations resolve at least 50 pairs of descending neurons supplying flight motor centers in the thoracic ganglia. The majority of descending neurons receive a distributed output from horizontal motion-sensitive neurons. However, the same descending neurons are also visited by numerous small-field retinotopic neurons from the lobula plate as well as hitherto undescribed small tangential neurons. Neuroanatomical studies, using cobalt, Golgi, and Texas red histology, demonstrate that these smaller inputs onto descending neurons have dendrites that are organized at specific strata in retinotopic neuropil and that these correspond to horizontal and vertical motion sensitivity layers. Conclusions that only a restricted number of wide-field neurons are necessary and sufficient for visually stabilized flight may be premature. Rather, neuroanatomical evidence suggests that descending neurons to the flight motor may each be selectively tuned to specific combinations of wide- and small-field visual cues, so providing a cooperative descending network controlling the rich repertoire of visually evoked flight behavior.
在双翅目昆虫中，大量行为学和电生理学研究支持这样一种观点：三个宽视野运动敏感切向神经元为驱动飞行中扭矩马达的特定通道提供了必要且充分的输入。本研究描述了对果蝇视叶中运动敏感神经纤维网与源自大脑特定区域并为节段性颈部和飞行运动神经纤维网提供神经支配的下行神经元之间关系进行神经解剖学研究的结果。目前的观察结果确定了至少50对为胸神经节中的飞行运动中枢提供神经支配的下行神经元。大多数下行神经元接收来自水平运动敏感神经元的分布式输出。然而，同样这些下行神经元也会受到来自小叶板的众多小视野视网膜拓扑神经元以及迄今未描述的小切向神经元的访问。使用钴、高尔基和德克萨斯红组织学的神经解剖学研究表明，这些对下行神经元的较小输入具有在视网膜拓扑神经纤维网的特定层中组织的树突，并且这些树突对应于水平和垂直运动敏感层。认为仅有限数量的宽视野神经元对于视觉稳定飞行是必要且充分的结论可能为时过早。相反，神经解剖学证据表明，向飞行运动的下行神经元可能各自被选择性地调整到宽视野和小视野视觉线索的特定组合，从而提供一个协作的下行网络来控制丰富的视觉诱发飞行行为。
