Prestimulus alpha power is related to the strength of stimulus representation

Abstract

Spatial attention can modulate behavioural performance and is associated with several electrophysiological markers. In this study, we used multivariate pattern analysis in electrophysiology data to investigate the effects of covert spatial attention on the quality of stimulus processing and underlying mechanisms. Our results show that covert spatial attention led to (i) an anticipatory alpha power desynchronization; (ii) enhanced stimuli identity information. Moreover, we found that alpha power fluctuations in anticipation of the relevant stimuli boosted and prolonged the coding of stimulus identity.

Spontaneous neural oscillations influence behavior and sensory representations by suppressing neuronal excitability

“…When distractors were absent (as in our paradigm), decoder accuracy was no longer related to prestimulus alpha power, suggesting that the effect on decoder accuracy might emerge when the task requires the suppression of taskirrelevant information, which is believed to be supported by alpha oscillations (Haegens et al, 2010). Moreover, in another study (Barne et al, 2020), lower decoder accuracy (i.e., AUC) was related to strong prestimulus alpha power in parieto-occipital EEG electrodes when attention was cued to the spatial location of the to-be-decoded sensory stimuli. Therefore, it is possible that decoder accuracy may be affected by attention-induced/local (as opposed to spontaneous/global) fluctuations of alpha oscillations.…”

“…We analyzed, first, a wide range of brain areas spanning from primary sensory cortices to frontal regions, and second, time windows of endogenous (prestimulus) and exogenous (poststimulus) processing. In this way, we overcome some limitations in previous studies estimating neural signals in a limited set of brain regions (e.g., Barne et al, 2020;Haegens et al, 2011), and/or following experimental events (e.g., saccades: Barczak et al, 2019), which cause phase-reset and thereby impact ongoing oscillatory estimates. Our findings show a negative relationship between alpha power and BHA occurring across the whole brain and both during the prestimulus and poststimulus window, consistent with the idea that functional inhibition reflects a general property of alpha oscillations.…”

“…Previous studies have analyzed how decoding performance is related to alpha oscillations, though the results were inconsistent, showing positive (Kayser et al, 2016;McNair et al, 2019), negative (Barne et al, 2020;van Ede et al, 2018), and null relationships (Griffiths et al, 2019). In the studies reporting a positive relationship, stimulus features were decoded using low-frequency EEG activity (1-70 Hz), which includes alpha oscillations.…”

Dynamic modulation of neural feedback processing and attention during spatial probabilistic learning

“…Specifically, preparatory activity in the sensory cortices is thought to facilitate attentional processing towards task relevant information, as it is correlated with subsequent N2pc amplitudes relative to the attended location ( Zhao et al., 2019 ) but also with decreased RTs ( van den Berg et al., 2016 ). Multivariate pattern analyses also recently showed that preparatory contralateral alpha power boosts subsequent stimulus processing ( Barne et al., 2020 ). Here, we extend those findings by reporting that preparatory alpha power also occurs in stimulus-reward learning tasks, as a direct function of the presentation of feedback related to the choice that was made.…”

Alpha and broadband high‐frequency activity track task dynamics and predict performance in controlled decision‐making

“…The combination of these signals allows the assessment of widespread dynamics, with alpha reflecting a mechanism of resource allocation and providing us a window on engaged versus disengaged areas and more fine-grained (in terms of spatio-temporal dynamics) broadband activations within those networks directly tied to perceptual and cognitive processing and subsequent behavior. Critically, this approach provides an avenue to tie together work showing that alpha impacts stimulus representation (e.g., Barne et al, 2020;Griffiths et al, 2019) and that alpha organizes neural activity both through power (our current focus) and phasic modulation (Chapeton et al, 2019;; we propose that the effect of alpha dynamics on information processing and subsequent behavior is mediated by a modulation of neuronal excitability. One outstanding question is whether this constitutes an active top-down mechanism or a reflection of underlying dynamics.…”