Gilbert C, Strausfeld N J
Arizona Research Laboratories Division of Neurobiology, University of Arizona, Tucson 85721.
J Comp Neurol. 1992 Feb 1;316(1):72-86. doi: 10.1002/cne.903160107.
In fleshflies, Sarcophaga bullata, intracellular recording and Lucifer yellow dye-filling have revealed small-field elements of sexually isomorphic retinotopic arrays in the lobula and lobula plate, the axons of which project to premotor channels in the deutocerebrum that supply head-turning and flight-steering motor neurons. The dendrites of the small-field elements visit very restricted oval areas of the retinotopic mosaic, comprising fields that are typically 6-8 input columns wide and 12-20 high. Their physiologically determined receptive fields are also small, typically 20 degrees or less in diameter. The neurons are hyperpolarized in stationary illumination and are transiently depolarized by light OFF and to a lesser degree by light ON. Motion of a striped grating elicits a periodic excitation at the fundamental or second harmonic of the stimulus temporal contrast frequency. The arrangement of these elements in retinotopic arrays with their small receptive fields and flicker-sensitive dynamic properties make these neurons well suited for the position-dependent, direction-insensitive detection of small objects in the fly's visual field, which is known to drive fixation and tracking.
在麻蝇（肉蝇属）中，细胞内记录和荧光黄染料填充揭示了小叶和小叶板中具有性别同构视网膜拓扑阵列的小视野元件，其轴突投射到中脑的运动前通道，该通道为头部转动和飞行转向运动神经元提供信号。小视野元件的树突分布在视网膜拓扑镶嵌的非常有限的椭圆形区域内，这些区域通常由6 - 8个输入列宽和12 - 20个高的区域组成。它们通过生理学方法确定的感受野也很小，直径通常为20度或更小。这些神经元在稳定光照下会发生超极化，并在光熄灭时短暂去极化，在光开启时去极化程度较小。条纹光栅的运动在刺激时间对比度频率的基波或二次谐波处引发周期性兴奋。这些元件在视网膜拓扑阵列中的排列，以及它们小的感受野和对闪烁敏感的动态特性，使得这些神经元非常适合对苍蝇视野中的小物体进行位置依赖、方向不敏感的检测，而这种检测已知会驱动注视和跟踪行为。
