Institute of Brain and Psychological Sciences, Sichuan Normal University, 610066 Chengdu, China.
Department of Psychology and Center for Mind/Brain Sciences, University of Trento, 38068 Rovereto, Italy.
Cereb Cortex. 2022 Nov 21;32(23):5455-5466. doi: 10.1093/cercor/bhac026.
Although sensory input is continuous, information must be combined over time to guide action and cognition, leading to the proposal of temporal sampling windows. A number of studies have suggested that a 10-Hz sampling window might be involved in the "frame rate" of visual processing. To investigate this, we tested the ability of participants to localize and enumerate 1 or 2 visual flashes presented either at near-threshold or full-contrast intensities, while recording magnetoencephalography. The inter-stimulus interval (ISI) between the 2 flashes was varied across trials. Performance in distinguishing between 1 and 2 flashes was linked to the alpha frequency, both at the individual level and trial-by-trial. Participants with a higher resting-state alpha peak frequency showed the greatest improvement in performance as a function of ISI within a 100-ms time window, while those with slower alpha improved more when ISI exceeded 100 ms. On each trial, correct enumeration (1 vs. 2) performance was paired with faster pre-stimulus instantaneous alpha frequency. Our results suggest that visual sampling/processing speed, linked to peak alpha frequency, is both an individual trait and can vary in a state-dependent manner.
尽管感觉输入是连续的，但信息必须随时间结合起来以指导行动和认知，从而提出了时间采样窗口。许多研究表明，10Hz 的采样窗口可能涉及视觉处理的“帧率”。为了研究这一点，我们测试了参与者在记录脑磁图的同时，定位和计数在近阈值或全对比度强度下呈现的 1 或 2 个视觉闪光的能力。两个闪光之间的刺激间隔（ISI）在试验之间变化。在区分 1 个和 2 个闪光的性能与个体水平和试验水平的阿尔法频率有关。静息状态阿尔法峰频率较高的参与者在 100ms 时间窗口内随 ISI 的变化表现出最大的性能提高，而阿尔法频率较慢的参与者在 ISI 超过 100ms 时表现出更大的提高。在每次试验中，正确计数（1 对 2）的性能与刺激前瞬间阿尔法频率较快相关。我们的结果表明，与峰值阿尔法频率相关的视觉采样/处理速度既是个体特征，也可以以状态依赖的方式变化。
