Dai Weifeng, Wang Tian, Li Yang, Yang Yi, Zhang Yange, Wu Yujie, Zhou Tingting, Yu Hongbo, Li Liang, Wang Yizheng, Wang Gang, Xing Dajun
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China.
College of Life Sciences, Beijing Normal University, Beijing, China.
PLoS Biol. 2025 Jan 8;23(1):e3002947. doi: 10.1371/journal.pbio.3002947. eCollection 2025 Jan.
Sensitivity to motion direction is a feature of visual neurons that is essential for motion perception. Recent studies have suggested that direction selectivity is re-established at multiple stages throughout the visual hierarchy, which contradicts the traditional assumption that direction selectivity in later stages largely derives from that in earlier stages. By recording laminar responses in areas 17 and 18 of anesthetized cats of both sexes, we aimed to understand how direction selectivity is processed and relayed across 2 successive stages: the input layers and the output layers within the early visual cortices. We found a strong relationship between the strength of direction selectivity in the output layers and the input layers, as well as the preservation of preferred directions across the input and output layers. Moreover, direction selectivity was enhanced in the output layers compared to the input layers, with the response strength maintained in the preferred direction but reduced in other directions and under blank stimuli. We identified a direction-tuned gain mechanism for interlaminar signal transmission, which likely originated from both feedforward connections across the input and output layers and recurrent connections within the output layers. This direction-tuned gain, coupled with nonlinearity, contributed to the enhanced direction selectivity in the output layers. Our findings suggest that direction selectivity in later cortical stages partially inherits characteristics from earlier cortical stages and is further refined by intracortical connections.
对运动方向的敏感性是视觉神经元的一个特征，对运动感知至关重要。最近的研究表明，方向选择性在整个视觉层级的多个阶段重新建立，这与传统假设相矛盾，传统假设认为后期阶段的方向选择性在很大程度上源自早期阶段。通过记录雌雄麻醉猫的17区和18区的层状反应，我们旨在了解方向选择性是如何在两个连续阶段进行处理和传递的：早期视觉皮层内的输入层和输出层。我们发现输出层和输入层之间方向选择性强度存在很强的关系，以及跨输入层和输出层的偏好方向得以保留。此外，与输入层相比，输出层的方向选择性增强，在偏好方向上反应强度保持，但在其他方向和空白刺激下降低。我们确定了一种用于层间信号传递的方向调谐增益机制，其可能源自跨输入层和输出层的前馈连接以及输出层内的循环连接。这种方向调谐增益，再加上非线性，导致了输出层方向选择性的增强。我们的研究结果表明，后期皮层阶段的方向选择性部分继承自早期皮层阶段的特征，并通过皮层内连接进一步细化。
