Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
J Vis. 2024 Oct 3;24(11):3. doi: 10.1167/jov.24.11.3.
Microsaccades are known to be associated with a deficit in perceptual detection performance for brief probe flashes presented in their temporal vicinity. However, it is still not clear how such a deficit might depend on the visual environment across which microsaccades are generated. Here, and motivated by studies demonstrating an interaction between visual background image appearance and perceptual suppression strength associated with large saccades, we probed peripheral perceptual detection performance of human subjects while they generated microsaccades over three different visual backgrounds. Subjects fixated near the center of a low spatial frequency grating, a high spatial frequency grating, or a small white fixation spot over an otherwise gray background. When a computer process detected a microsaccade, it presented a brief peripheral probe flash at one of four locations (over a uniform gray background) and at different times. After collecting full psychometric curves, we found that both perceptual detection thresholds and slopes of psychometric curves were impaired for peripheral flashes in the immediate temporal vicinity of microsaccades, and they recovered with later flash times. Importantly, the threshold elevations, but not the psychometric slope reductions, were stronger for the white fixation spot than for either of the two gratings. Thus, like with larger saccades, microsaccadic suppression strength can show a certain degree of image dependence. However, unlike with larger saccades, stronger microsaccadic suppression did not occur with low spatial frequency textures. This observation might reflect the different spatiotemporal retinal transients associated with the small microsaccades in our study versus larger saccades.
微扫视已知与在其时间附近呈现的短暂探测闪光的感知检测性能缺陷有关。然而，目前尚不清楚这种缺陷如何取决于生成微扫视的视觉环境。在这里，并且受到研究的启发，这些研究表明视觉背景图像外观与与大扫视相关的感知抑制强度之间存在相互作用，我们在三种不同的视觉背景下探测人类受试者的外围感知检测性能。受试者在低空间频率光栅、高空间频率光栅或小的白色固定点附近的中心注视，背景为灰色。当计算机程序检测到微扫视时，它会在四个位置之一（在均匀的灰色背景上）和不同的时间呈现短暂的外围探测闪光。收集完整的心理物理曲线后，我们发现，微扫视的瞬时时间内，外围闪光的感知检测阈值和心理物理曲线的斜率都受到损害，随着闪光时间的推移而恢复。重要的是，与两种光栅相比，白色固定点的阈值升高，但不是心理物理斜率降低，比微扫视更强。因此，与较大的扫视一样，微扫视抑制强度可以表现出一定程度的图像依赖性。然而，与较大的扫视不同，在低空间频率纹理中不会发生更强的微扫视抑制。这种观察可能反映了我们研究中的小微扫视与较大扫视相比，与不同的时空视网膜瞬变相关。
