Understanding the neurocognitive mechanisms of alpha-band brain oscillations using concurrent EEG-fMRI recordings

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PROJECT SUMMARY Alpha oscillations, 8-12Hz fluctuations in neural signals, are robust across species, covary with states of attention, and are impacted in multiple disorder states, and in recent years have become a candidate biomarker of attention system efficacy, particularly in disorders of attention such as attention deficit hyperactivity disorder (ADHD). Yet, despite this broad acceptance of alpha oscillations as an attention read-out signal, significant questions remain regarding the mechanisms and thus interpretation of alpha oscillations. The goal of our research is to answer the central question of whether the neurocognitive mechanisms of alpha oscillations are strictly attentional or whether they more closely reflect other mechanisms such as local processing dynamics or system-wide tonic alertness. To address this question, we will record EEG and fMRI concurrently in human participants, and employ causal models, to identify functional connectivity (3T scanning) and laminar activation (7T scanning) of visual cortex during alpha modulations across different task contexts. We aim to test (1) if alpha increases reflect cortical suppression or tonic alertness, (2) if alpha decreases reflect cortical enhancement or local information flow, and, (3) if alpha modulations reflect top-down signals or if they are a passive by-product of either cortico-cortical or thalamo-cortical drivers. The results will directly impact interpretation of alpha oscillations as a biomarker of attention-system efficacy in ADHD and related conditions, outlining a model that can be targeted in treatment or monitoring of attention deficits in ADHD. By accounting for variability in existing findings, this work will also differentiate between two theoretical frameworks of alpha oscillations and speak to recent debates on whether alpha oscillations are a correlate or a product of top-down signals.