The primate superior colliculus (SC) has recently been shown to possess both a large foveal representation as well as a varied visual processing repertoire. This structure is also known to contribute to eye movement generation. Here we describe our current understanding of how SC visual and movement-related signals interact within the realm of small eye movements associated with the foveal scale of visuomotor behavior. Within the SC's foveal representation, there is a full spectrum of visual, visual-motor, and motor-related discharge for fixational eye movements. Moreover, a substantial number of neurons only emit movement-related discharge when microsaccades are visually-guided, but not when similar movements are generated towards a blank. This represents a particularly striking example of integrating vision and action at the foveal scale. Beyond that, SC visual responses themselves are strongly modulated, and in multiple ways, by the occurrence of small eye movements. Intriguingly, this impact can extend to eccentricities well beyond the fovea, causing both sensitivity enhancement and suppression in the periphery. Because of large foveal magnification of neural tissue, such long-range eccentricity effects are neurally warped into smaller differences in anatomical space, providing a structural means for linking peripheral and foveal visual modulations around fixational eye movements. Finally, even the retinal-image visual flows associated with tiny fixational eye movements are signaled fairly faithfully by peripheral SC neurons with relatively large receptive fields. These results demonstrate how studying active vision at the foveal scale represents an opportunity for understanding primate vision during natural behaviors involving ever-present foveating eye movements.

中文翻译：

---

灵长类动物上丘中央凹尺度的主动视觉

灵长类动物上丘 (SC) 最近已被证明具有大的中央凹表示以及各种视觉处理功能。这种结构也有助于眼球运动的产生。在这里，我们描述了我们目前对 SC 视觉和运动相关信号如何在与视觉运动行为的中央凹尺度相关的小眼球运动领域内相互作用的理解。在 SC 的中心凹表现中，有全方位的视觉、视觉运动和运动相关放电，用于注视眼球运动。此外，相当数量的神经元仅在视觉引导微扫视时才发出与运动相关的放电，而在朝向空白产生类似运动时则不会。这是在中央凹尺度上整合视觉和行动的一个特别突出的例子。除此之外，SC 视觉反应本身也受到微小眼球运动的强烈调节，并以多种方式进行调节。有趣的是，这种影响可以扩展到远远超出中央凹的离心率，导致周边的灵敏度增强和抑制。由于神经组织的中央凹放大倍数较大，这种远距离偏心效应在神经上被扭曲成解剖空间中较小的差异，从而提供了一种结构手段，用于将围绕注视眼球运动的周边和中央凹视觉调制联系起来。最后，即使是与微小注视眼球运动相关的视网膜图像视觉流，也能由具有相对较大感受野的外周 SC 神经元相当忠实地发出信号。