Department of Neuroscience, University of Arizona, Tucson, Arizona 85721, USA.
J Neurosci. 2012 May 2;32(18):6061-71. doi: 10.1523/JNEUROSCI.0221-12.2012.
Studying the insect visual system provides important data on the basic neural mechanisms underlying visual processing. As in vertebrates, the first step in visual processing in insects is through a series of retinotopic neurons. Recent studies on flies have found that these converge onto assemblies of columnar neurons in the lobula, the axons of which segregate to project to discrete optic glomeruli in the lateral protocerebrum. This arrangement is much like the fly's olfactory system, in which afferents target uniquely identifiable olfactory glomeruli. Here, whole-cell patch recordings show that even though visual primitives are unreliably encoded by single lobula output neurons because of high synaptic noise, they are reliably encoded by the ensemble of outputs. At a glomerulus, local interneurons reliably code visual primitives, as do projection neurons conveying information centrally from the glomerulus. These observations demonstrate that in Drosophila, as in other dipterans, optic glomeruli are involved in further reconstructing the fly's visual world. Optic glomeruli and antennal lobe glomeruli share the same ancestral anatomical and functional ground pattern, enabling reliable responses to be extracted from converging sensory inputs.
研究昆虫的视觉系统为视觉处理的基本神经机制提供了重要数据。与脊椎动物一样，昆虫视觉处理的第一步是通过一系列的视网膜神经元。最近对苍蝇的研究发现，这些神经元汇聚到小叶中的柱状神经元集合上，其轴突分离投射到外侧原脑的离散光感受器小球中。这种排列方式非常类似于苍蝇的嗅觉系统，其中传入神经靶向独特可识别的嗅觉小球。在这里，全细胞贴片记录显示，尽管由于突触噪声高，单个小叶输出神经元对视觉原始信号的编码不可靠，但通过输出的整体编码可以可靠地编码。在一个小球体中，局部中间神经元可靠地对视觉原始信号进行编码，从中枢传递信息的投射神经元也是如此。这些观察结果表明，在果蝇中，与其他双翅目昆虫一样，光感受器小球参与进一步重建果蝇的视觉世界。光感受器小球和触角叶小球具有相同的祖先解剖和功能基础模式，能够从汇聚的感觉输入中提取可靠的反应。
