Individualized alpha entrainment enables sustained perceptual improvement

Abstract

Training is known to improve our ability to make perceptual judgments (e.g. detect patterns in cluttered environments) and trigger plasticity in the visual system. The parietal cortex has been linked to critical early stages of this perceptual learning; yet, the interactions between parietal and visual areas that support learning remain unclear. Here, we employ transcranial magnetic stimulation (TMS) with concurrently recorded electroencephalography (EEG) to entrain alpha oscillations in the parietal cortex and test the role of alpha oscillations in gating inter-areal interactions for perceptual learning. We used stimulation frequencies that were matched or non-matched to each individual participant’s alpha frequency. We found that both matched and non-matched stimulation (compared to sham) improved perceptual performance during active stimulation. Sustained perceptual improvement was observed for individuals in the matched group and the non-matched group stimulated at lower frequencies compared to their individual peak alpha. EEG results suggest that pre-stimulus alpha power at occipital sites was closely associated with the transient “online” stimulation. Sustained behavioural improvement following individualized intervention was associated with boosted alpha power and modulation of an early component of the visual evoked potential. Taken together, these results provide evidence that parietal-alpha mechanisms contribute to both short- and longer-term behavioural enhancement, potentially by optimising visual cortex processing to support target detection in cluttered environments.