Department of Biological Structure, University of Washington, Seattle, WA, 98195, USA.
Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA.
Nat Commun. 2022 May 23;13(1):2862. doi: 10.1038/s41467-022-30405-5.
From mouse to primate, there is a striking discontinuity in our current understanding of the neural coding of motion direction. In non-primate mammals, directionally selective cell types and circuits are a signature feature of the retina, situated at the earliest stage of the visual process. In primates, by contrast, direction selectivity is a hallmark of motion processing areas in visual cortex, but has not been found in the retina, despite significant effort. Here we combined functional recordings of light-evoked responses and connectomic reconstruction to identify diverse direction-selective cell types in the macaque monkey retina with distinctive physiological properties and synaptic motifs. This circuitry includes an ON-OFF ganglion cell type, a spiking, ON-OFF polyaxonal amacrine cell and the starburst amacrine cell, all of which show direction selectivity. Moreover, we discovered that macaque starburst cells possess a strong, non-GABAergic, antagonistic surround mediated by input from excitatory bipolar cells that is critical for the generation of radial motion sensitivity in these cells. Our findings open a door to investigation of a precortical circuitry that computes motion direction in the primate visual system.
从老鼠到灵长类动物，我们对运动方向的神经编码的理解存在明显的不连续性。在非灵长类哺乳动物中，定向选择细胞类型和回路是视网膜的特征，位于视觉过程的最早阶段。相比之下，在灵长类动物中，运动处理区域在视觉皮层中具有方向选择性，但尽管进行了大量研究，仍未在视网膜中发现。在这里，我们结合了光诱发反应的功能记录和连接体重建，以鉴定具有独特生理特性和突触模式的猕猴视网膜中的多种方向选择性细胞类型。该回路包括一个 ON-OFF 神经节细胞类型、一个放电的 ON-OFF 多轴突无长突细胞和星爆状无长突细胞，所有这些细胞都表现出方向选择性。此外，我们发现猕猴星爆状无长突细胞具有强烈的非 GABA 能拮抗环绕，由兴奋性双极细胞输入介导，这对于这些细胞中径向运动敏感性的产生至关重要。我们的发现为研究灵长类动物视觉系统中计算运动方向的皮质前回路开辟了一扇门。
