Streets Amy, England Hayley, Marshall Justin
Queensland Brain Institute, University of Queensland, Brisbane, Australia.
J Comp Neurol. 2025 Jun;533(6):e70063. doi: 10.1002/cne.70063.
The lamina is the first optic neuropil and visual information integration station in crustaceans and insects, containing synaptic connections between photoreceptors and first-order interneurons. The lamina circuitry in mantis shrimp (stomatopods) is both interesting and complex, as there are 16 different types of photoreceptors contained within the mid-band region of the eye. Using serial block-face scanning electron microscopy, we have reconstructed photoreceptor terminals and lamina interneurons in two major superfamilies with different visual ecologies. Neurons follow the same general pattern as other crustaceans but with notable differences in gross anatomy from insects. The photoreceptors form bulbous terminals in the lamina, following the same overall connectivity pattern in all lamina cartridges across species examined and eye regions. The photoreceptor terminals themselves appear to be complex, with many large mitochondria, a notable difference between insects and stomatopods. Connectivity between photoreceptors and interneurons, as well as cross-cartridge connections, is estimated based on neuronal overlap. Lamina monopolar cells follow previous research in stomatopods and crustaceans, with a set of common neuron types that may provide the beginning of an opponency circuit. Additionally, neurons that extend beyond their parent cartridge in the midband show a preference for branching between rows within the same visual column of cells, as well as some connections within the same row. This added complexity suggests that the stomatopod lamina performs a unique processing of visual signals versus other crustaceans and insects and provides further evidence for the emerging hypotheses around the processing of information by the scanning visual system of stomatopods.
在甲壳类动物和昆虫中，神经纤维层是首个视觉神经纤维网和视觉信息整合站，包含光感受器与一级中间神经元之间的突触连接。螳螂虾（口足类动物）的神经纤维层回路既有趣又复杂，因为其眼睛的中带区域包含16种不同类型的光感受器。利用连续块面扫描电子显微镜，我们重建了具有不同视觉生态的两个主要超科中的光感受器终端和神经纤维层中间神经元。神经元遵循与其他甲壳类动物相同的一般模式，但在大体解剖结构上与昆虫有显著差异。光感受器在神经纤维层中形成球状终端，在所检查的所有物种和眼区的神经纤维层小眼束中遵循相同的整体连接模式。光感受器终端本身似乎很复杂，有许多大的线粒体，这是昆虫和口足类动物之间的一个显著差异。基于神经元重叠来估计光感受器与中间神经元之间的连接以及跨小眼束连接。神经纤维层单极细胞遵循之前对口足类动物和甲壳类动物的研究结果，有一组常见的神经元类型，可能构成了拮抗回路的开端。此外，在中带区域延伸到其母小眼束之外的神经元倾向于在同一视觉细胞列内的行之间分支，以及在同一行内形成一些连接。这种增加的复杂性表明，与其他甲壳类动物和昆虫相比，口足类动物的神经纤维层对视觉信号进行独特的处理，并为围绕口足类动物扫描视觉系统信息处理的新假说提供了进一步的证据。
