Biosciences Institute, Henry Wellcome Building for Neuroecology, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2020 Mar;206(2):165-181. doi: 10.1007/s00359-020-01405-x. Epub 2020 Feb 22.
Praying mantids are the only insects proven to have stereoscopic vision (stereopsis): the ability to perceive depth from the slightly shifted images seen by the two eyes. Recently, the first neurons likely to be involved in mantis stereopsis were described and a speculative neuronal circuit suggested. Here we further investigate classes of neurons in the lobula complex of the praying mantis brain and their tuning to stereoscopically-defined depth. We used sharp electrode recordings with tracer injections to identify visual projection neurons with input in the optic lobe and output in the central brain. In order to measure binocular response fields of the cells the animals watched a vertical bar stimulus in a 3D insect cinema during recordings. We describe the binocular tuning of 19 neurons projecting from the lobula complex and the medulla to central brain areas. The majority of neurons (12/19) were binocular and had receptive fields for both eyes that overlapped in the frontal region. Thus, these neurons could be involved in mantis stereopsis. We also find that neurons preferring different contrast polarity (bright vs dark) tend to be segregated in the mantis lobula complex, reminiscent of the segregation for small targets and widefield motion in mantids and other insects.
螳螂是唯一被证实具有立体视觉（立体视）的昆虫：能够从两只眼睛看到的略微移位的图像中感知深度。最近，描述了第一个可能参与螳螂立体视的神经元，并提出了一个推测的神经元回路。在这里，我们进一步研究了螳螂大脑中的小叶复合体内的神经元类别及其对立体定义深度的调谐。我们使用带有示踪剂注射的锋利电极记录来识别在视叶中有输入并在中枢脑中有输出的视觉投射神经元。为了测量细胞的双眼反应场，动物在记录过程中观看了 3D 昆虫电影院中的垂直条刺激。我们描述了 19 个从小叶复合体和中脑投射到中枢脑区的神经元的双眼调谐。大多数神经元（19/19）是双眼的，并且双眼的感受野在前区重叠。因此，这些神经元可能参与了螳螂的立体视。我们还发现，偏好不同对比度极性（亮与暗）的神经元倾向于在螳螂小叶复合体内分离，这让人联想到在螳螂和其他昆虫中，小目标和宽视野运动的分离。
