Section Brain Stimulation and Cognition, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229 EV, Maastricht, The Netherlands.
Maastricht Brain Imaging Centre (MBIC), Maastricht University, Maastricht, The Netherlands.
Sci Rep. 2023 Aug 5;13(1):12707. doi: 10.1038/s41598-023-38968-z.
Recently it has been discovered that visuospatial attention operates rhythmically, rather than being stably employed over time. A low-frequency 7-8 Hz rhythmic mechanism coordinates periodic windows to sample relevant locations and to shift towards other, less relevant locations in a visual scene. Rhythmic sampling theories would predict that when two locations are relevant 8 Hz sampling mechanisms split into two, effectively resulting in a 4 Hz sampling frequency at each location. Therefore, it is expected that rhythmic sampling is influenced by the relative importance of locations for the task at hand. To test this, we employed an orienting task with an arrow cue, where participants were asked to respond to a target presented in one visual field. The cue-to-target interval was systematically varied, allowing us to assess whether performance follows a rhythmic pattern across cue-to-target delays. We manipulated a location's task relevance by altering the validity of the cue, thereby predicting the correct location in 60%, 80% or 100% of trials. Results revealed significant 4 Hz performance fluctuations at cued right visual field targets with low cue validity (60%), suggesting regular sampling of both locations. With high cue validity (80%), we observed a peak at 8 Hz towards non-cued targets, although not significant. These results were in line with our hypothesis suggesting a goal-directed balancing of attentional sampling (cued location) and shifting (non-cued location) depending on the relevance of locations in a visual scene. However, considering the hemifield specificity of the effect together with the absence of expected effects for cued trials in the high valid conditions we further discuss the interpretation of the data.
最近发现，视空间注意力是有节奏地运作的，而不是稳定地随时间持续运作。一种低频 7-8Hz 的节奏机制协调周期性窗口，以采样相关位置，并在视觉场景中转移到其他不太相关的位置。节奏采样理论预测，当两个位置都相关时，8Hz 的采样机制会分裂成两个，有效地导致每个位置的采样频率为 4Hz。因此，预计节奏采样会受到当前任务中位置相对重要性的影响。为了验证这一点，我们使用了带有箭头提示的定向任务，要求参与者对呈现于一个视觉场中的目标做出反应。提示-目标间隔被系统地改变，从而使我们能够评估在提示-目标延迟之间的表现是否遵循节奏模式。我们通过改变提示的有效性来操纵位置的任务相关性，从而在 60%、80%或 100%的试验中预测正确的位置。结果显示，在提示右视觉场目标时，低提示有效性（60%）时，4Hz 的表现波动显著，这表明对两个位置进行了有规律的采样。在高提示有效性（80%）时，尽管不显著，我们观察到非提示目标的 8Hz 峰值。这些结果与我们的假设一致，即根据视觉场景中位置的相关性，有目的地平衡注意力采样（提示位置）和转移（非提示位置）。然而，考虑到该效应的半视野特异性以及在高有效条件下对提示试验的预期效应缺失，我们进一步讨论了数据的解释。
