A multichannel MEG time-frequency analysis framework for detecting stage -specific effects of spatial distraction in...

Spatial distraction can disrupt visual-spatial working memory (VSWM), but its stage-dependent effects on multichannel neural dynamics remain insufficiently characterized. This study presents a multichannel magnetoencephalography (MEG) time-frequency analysis framework to detect stage-specific oscillatory responses to spatial distraction during a VSWM task.

MEG signals were recorded from healthy participants under Distractor and No-distractor conditions and analyzed across encoding, maintenance, and retrieval/decision epochs. Time-frequency power was estimated in the delta, theta, alpha, beta, and gamma bands, and condition differences were evaluated using sensor-level spatiotemporal cluster-based permutation testing and Bonferroni correction within each predefined epoch.

The proposed analysis revealed a clear stage-specific pattern, with the most prominent modulation occurring during maintenance. Specifically, distraction induced robust and sustained increases in theta-, alpha-, and beta-band power during the retention interval (all cluster-level p < 0.01). Theta activity increased rapidly after maintenance onset and remained elevated throughout the full maintenance period over bilateral temporal, and widespread parieto-occipital sensors, while alpha and beta enhancements also showed temporally continuous and spatially stable patterns across widespread sensor networks.

These findings highlight sustained large-scale oscillatory modulation as a key neural signature of distraction during mnemonic maintenance. The study provides an interpretable multichannel signal-analysis perspective on distraction effects in working memory and offers a practical framework for stage-resolved analysis of brain dynamics in cognitive tasks.