Karvat Golan, Ofir Nir, Landau Ayelet N
Hebrew University of Jerusalem.
J Cogn Neurosci. 2024 Apr 1;36(4):614-631. doi: 10.1162/jocn_a_02088.
Perception is suggested to occur in discrete temporal windows, clocked by cycles of neural oscillations. An important testable prediction of this theory is that individuals' peak frequencies of oscillations should correlate with their ability to segregate the appearance of two successive stimuli. An influential study tested this prediction and showed that individual peak frequency of spontaneously occurring alpha (8-12 Hz) correlated with the temporal segregation threshold between two successive flashes of light [Samaha, J., & Postle, B. R. The speed of alpha-band oscillations predicts the temporal resolution of visual perception. Current Biology, 25, 2985-2990, 2015]. However, these findings were recently challenged [Buergers, S., & Noppeney, U. The role of alpha oscillations in temporal binding within and across the senses. Nature Human Behaviour, 6, 732-742, 2022]. To advance our understanding of the link between oscillations and temporal segregation, we devised a novel experimental approach. Rather than relying entirely on spontaneous brain dynamics, we presented a visual grating before the flash stimuli that is known to induce continuous oscillations in the gamma band (45-65 Hz). By manipulating the contrast of the grating, we found that high contrast induces a stronger gamma response and a shorter temporal segregation threshold, compared to low-contrast trials. In addition, we used a novel tool to characterize sustained oscillations and found that, for half of the participants, both the low- and high-contrast gratings were accompanied by a sustained and phase-locked alpha oscillation. These participants tended to have longer temporal segregation thresholds. Our results suggest that visual stimulus drive, reflected by oscillations in specific bands, is related to the temporal resolution of visual perception.
知觉被认为发生在离散的时间窗口中，由神经振荡周期计时。该理论一个重要的可检验预测是，个体的振荡峰值频率应与其区分两个连续刺激外观的能力相关。一项有影响力的研究检验了这一预测，结果表明，自发产生的阿尔法波（8 - 12赫兹）的个体峰值频率与两次连续闪光之间的时间分离阈值相关[萨马哈，J.，& 波斯特尔，B. R.阿尔法波段振荡的速度预测视觉感知的时间分辨率。《当代生物学》，25，2985 - 2990，2015年]。然而，这些发现最近受到了挑战[比尔格斯，S.，& 诺彭尼，U.阿尔法振荡在不同感官内和跨感官的时间绑定中的作用。《自然·人类行为》，6，732 - 742，2022年]。为了增进我们对振荡与时间分离之间联系的理解，我们设计了一种新颖的实验方法。我们并非完全依赖自发的脑动力学，而是在闪光刺激之前呈现一个视觉光栅，已知该光栅会在伽马波段（45 - 65赫兹）诱发持续振荡。通过操纵光栅的对比度，我们发现与低对比度试验相比，高对比度会诱发更强的伽马反应和更短的时间分离阈值。此外，我们使用一种新颖的工具来表征持续振荡，结果发现，对于一半的参与者来说，低对比度和高对比度光栅都伴随着持续且锁相的阿尔法振荡。这些参与者往往有更长的时间分离阈值。我们的结果表明，由特定波段的振荡反映的视觉刺激驱动与视觉感知的时间分辨率有关。
