Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut 06520, USA.
J Neurosci. 2010 Aug 4;30(31):10493-506. doi: 10.1523/JNEUROSCI.1546-10.2010.
With each eye movement, the image of the world received by the visual system changes dramatically. To maintain stable spatiotopic (world-centered) visual representations, the retinotopic (eye-centered) coordinates of visual stimuli are continually remapped, even before the eye movement is completed. Recent psychophysical work has suggested that updating of attended locations occurs as well, although on a slower timescale, such that sustained attention lingers in retinotopic coordinates for several hundred milliseconds after each saccade. To explore where and when this "retinotopic attentional trace" resides in the cortical visual processing hierarchy, we conducted complementary functional magnetic resonance imaging and event-related potential (ERP) experiments using a novel gaze-contingent task. Human subjects executed visually guided saccades while covertly monitoring a fixed spatiotopic target location. Although subjects responded only to stimuli appearing at the attended spatiotopic location, blood oxygen level-dependent responses to stimuli appearing after the eye movement at the previously, but no longer, attended retinotopic location were enhanced in visual cortical area V4 and throughout visual cortex. This retinotopic attentional trace was also detectable with higher temporal resolution in the anterior N1 component of the ERP data, a well established signature of attentional modulation. Together, these results demonstrate that, when top-down spatiotopic signals act to redirect visuospatial attention to new retinotopic locations after eye movements, facilitation transiently persists in the cortical regions representing the previously relevant retinotopic location.
每次眼球运动，视觉系统接收到的世界图像都会发生巨大变化。为了保持稳定的空间（以世界为中心）视觉表示，即使在眼球运动完成之前，视觉刺激的视网膜（以眼睛为中心）坐标也会不断重新映射。最近的心理物理学研究表明，即使在较慢的时间尺度上，注意位置也会更新，因此，在每次眼跳后，持续的注意力会在视网膜坐标中持续几百毫秒。为了探索这个“视网膜注意痕迹”在皮质视觉处理层次结构中的位置和时间，我们使用一种新的注视相关任务进行了互补的功能磁共振成像和事件相关电位（ERP）实验。人类受试者在执行视觉引导的眼球运动的同时，秘密监测一个固定的空间位置。尽管受试者仅对出现在注视的空间位置的刺激做出反应，但在眼球运动后出现在先前但不再被注视的视网膜位置的刺激的血氧水平依赖反应在 V4 区和整个视觉皮层中得到增强。这种视网膜注意痕迹也可以在 ERP 数据的前 N1 成分中以更高的时间分辨率检测到，这是注意力调节的一个公认特征。这些结果共同表明，当自上而下的空间信号在眼球运动后将视空间注意力重新引导到新的视网膜位置时，在代表先前相关视网膜位置的皮质区域中，促进作用会短暂持续存在。
