Abstract
Massed synchronised neuronal firing is detrimental to information processing. When networks of task-irrelevant neurons fire in unison, they mask the signal generated by task-critical neurons. On a macroscopic level, such synchronisation can contribute to alpha/beta (8-30 Hz) oscillations. Reducing the amplitude of these oscillations, therefore, may enhance information processing. Here, we test this hypothesis. Twenty-one participants completed an associative memory task while undergoing simultaneous EEG-fMRI recordings. Using representational similarity analysis, we quantified the amount of stimulus-specific information represented within the BOLD signal on every trial. When correlating this metric with concurrently-recorded alpha/beta power, we found a significant negative correlation which indicated that as post-stimulus alpha/beta power decreased, stimulus-specific information increased. Critically, we found this effect in three unique tasks: visual perception, auditory perception, and visual memory retrieval, indicating that this phenomenon transcends both stimulus modality and cognitive task. These results indicate that alpha/beta power decreases parametrically track the fidelity of both externally-presented and internally-generated stimulus-specific information represented within the cortex.
Highlights
While numerous domain-general processes have already been ascribed to alpha/beta oscillations, we provide empirical evidence in support of a new perspective: alpha/beta power decreases are a proxy for information processing
We provide empirical evidence to suggest that task-induced alpha/beta power decreases track the fidelity of stimulus-specific information represented within the cortex
Our results suggest that these alpha/beta power decreases are a proxy for information processing
Summary
Alpha/beta activity displays an intimate link to behaviour; engaging in a cognitive task produces a large reduction in the alpha/beta power (amplitude squared) These task-induced power decreases are ubiquitous, and can be observed across species (including humans [Pfurtscheller et al, 1994], macaques [Haegens et al, 2011], rodents [Wiest and Nicolelis, 2003] and cats [Chatila et al, 1992]), sensory modalities (including visual [Pfurtscheller et al, 1994], auditory [Krause et al, 1994], and somatosensory [Crone et al, 1998] domains), and cognitive tasks (including perception [Pfurtscheller et al, 1994; Krause et al, 1994; Crone et al, 1998], memory formation/retrieval [Griffiths et al, 2016; Hanslmayr et al, 2009; Waldhauser et al, 2016], and language processing [Obleser and Weisz, 2012]). While numerous domain-general processes have already been ascribed to alpha/beta oscillations (e.g. idling [Pfurtscheller et al, 1996]; inhibition [Jensen and Mazaheri, 2010; Klimesch et al, 2007]), we provide empirical evidence in support of a new perspective: alpha/beta power decreases are a proxy for information processing
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