Alpha Frequency Shapes Perceptual Sensitivity by Modulating Optimal Phase Likelihood

Whether alpha frequency oscillations orchestrate the pace of sensory sampling is current matter of debate. We tested this hypothesis by investigating whether pre-stimulus instantaneous alpha frequency (IAF) accounted for perceptual sensitivity. Our results strongly support the pivotal role of IAF in shaping the accuracy of sensory acquisition. Spontaneous IAF inter-trial fluctuations emerged as a robust predictor of perceptual decision-making sensitivity and accuracy, with higher pace accounting for higher sensory precision, a finding robustly validated through large-scale analyses, Bayesian statistics, and advanced computational models. Crucially, we provide unprecedented insights into the neural mechanisms through which IAF influences perceptual decisions. Specifically, IAF determines the extent of phase angles covered within the stimulus timeframe. Higher probability for covering optimal alpha phases during same stimulus presentation, crucial for accurate perception, is intrinsic to higher rather than lower IAF.