Gronenberg W, Strausfeld N J
Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson 85721.
J Comp Neurol. 1992 Feb 1;316(1):87-103. doi: 10.1002/cne.903160108.
The responses of dorsal descending neurons suggest great versatility of the visual system in detecting features of the visual world. Although wide-field motion-sensitive neurons respond to symmetric visual flow fields presented to both eyes, other neurons are known to respond selectively to asymmetric movement of the visual surround. The present account distinguishes yet a third class of descending neurons (DNs) that is selectively activated by local presentation of moving gratings or small contrasting objects. Excitation of these DNs in response to local motion contrasts with their inhibitory responses to wide-field motion. The described DNs invade dorsal neuropil of the pro- and mesothoracic ganglia where they converge with other morphologically and physiologically characterized descending elements. Axon collaterals of DNs visit thoracic neuropil containing the dendrites of motor neurons supplying indirect neck and flight muscles. The present results are discussed with respect to the organization of small-field retinotopic outputs from the lobula, and with respect to the parallel projection of many information channels from the brain to the neck and flight motors.
背侧下行神经元的反应表明视觉系统在检测视觉世界特征方面具有很强的通用性。尽管宽视野运动敏感神经元对呈现给双眼的对称视觉流场有反应，但已知其他神经元对视觉环境的不对称运动有选择性反应。本文描述了另一类下行神经元（DNs），它们被移动光栅或小对比度物体的局部呈现选择性激活。这些DNs对局部运动的兴奋与它们对宽视野运动的抑制反应形成对比。所描述的DNs侵入前胸和中胸神经节的背侧神经纤维网，在那里它们与其他形态和生理特征的下行元件汇聚。DNs的轴突侧支到达胸神经纤维网，该神经纤维网包含为间接颈部和飞行肌肉提供运动神经元的树突。本文根据小叶小视野视网膜定位输出的组织，以及从大脑到颈部和飞行运动的许多信息通道的平行投射来讨论目前的结果。
