Dynamics of alpha suppression and enhancement may be related to resource competition in cross-modal cortical regions

Clements, Grace M.; Gyurkovics, Máté; Low, Kathy A.; Beck, Diane M.; Fabiani, Monica; Gratton, Gabriele

doi:10.1016/j.neuroimage.2022.119048

Cited by 7 publications

(14 citation statements)

References 65 publications

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“…The post-stimulus suppression of alpha activity, which was observed to be clearly oscillatory both pre- and post-event in our study, is also thought to index the destabilization of current representations to allow for the instantiation of new ones (Gratton, 2018; Clements et al, 2022). However, the selective attention mechanisms likely reflected by alpha activity are more local and specific to goal-relevant areas than the large-scale and seemingly indiscriminate global inhibition suggested by the scalp distribution of the 1/ f shift.…”

Section: Discussionmentioning

confidence: 55%

“…Data collected for a different project (described in Clements et al, 2022) were re-analyzed for the current study. Participants completed two auditory tasks, a passive listening task and an oddball task in separate sessions.…”

Section: Methodsmentioning

confidence: 99%

“…In the oddball task, trials were sorted into three conditions based on the trial sequence (Clements et al, 2022) to control for well-established sequential effects in oddball paradigms (Brumback et al, 2005). The conditions were: frequent pips preceded by another frequent pip (frequent- frequent , approximately 64% of trials), frequent pips preceded by a rare pip (rare- frequent , approximately 16% of trials), and rare pips preceded by a frequent pip (frequent- rare , approximately 16% of trials).…”

Section: Methodsmentioning

confidence: 99%

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Stimulus-induced changes in 1/f-like background activity in EEG

Gyurkovics

Clements

Low

et al. 2021

Preprint

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Neural activity contains oscillatory components (i.e., narrowband oscillations) and non-oscillatory components (e.g., event-related potentials [ERPs] and 1/f-like background activity). Here, surface-level EEG data was analyzed to investigate how the spectral content of neural activity below 25 Hz changes from before to after an event. We focused on changes in non-oscillatory background activity, a spectral component often assumed to be static across time in time-frequency analyses. During a simple auditory perception task (n = 46) and an auditory oddball task (n = 23), we found an apparent increase in the offset and a decrease in the slope of 1/f activity from before to after a tone. Importantly, however, these changes in non-oscillatory background activity were almost completely accounted for by the emergence of ERPs in response to the stimulus in frequencies below the alpha range (8-12 Hz). Our findings suggest that post-event spectral changes below 25 Hz can be modelled as the sum of pre-event non-oscillatory activity, the spectrum of the ERP, and an independent alpha component that is modulated in amplitude, but not elicited, by the event. Theta activity (4-8 Hz), however, was not present before the event and appeared to be phase-locked to it. The theoretical and methodological implications of our findings regarding the nature and origin of 1/f activity, and the interpretation of low-frequency activity in the time-frequency domain are discussed.

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Section: Discussionmentioning

confidence: 55%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Stimulus-induced changes in 1/f-like background activity in EEG

Gyurkovics

Clements

Low

et al. 2021

Preprint

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“…Somatosensory preparatory processes are easiest to test, which would bolster our claims about the role of alpha suppression as a general index of cognitive control processes across modalities. Given that this study was conducted exclusively with open eyes, we did not observe post-stimulus alpha enhancement, which has been previously reported with eyes closed (Clements et al, 2022). Some elegant experiments could be designed to assess unimodal auditory attention with closed eyes -in which alpha enhancement would be expected -or bimodal auditory and somatosensory attention with the eyes open or closed.…”

Section: Discussionmentioning

confidence: 51%

“…A condition-specific baseline was used because the content of the previous trial had meaning (switch vs. repeat) which could result in lingering unique activity in the baseline period. We have previously shown that, compared to divisive baselining, subtractive baselining minimizes the potential of Type I errors that might occur because of the aperiodic, 1/f component of power spectra in certain situations (Clements et al, 2021(Clements et al, , 2022Gyurkovics et al, 2021). The power in the baseline period (-750 to -250 ms) was thus subtracted from power values across the whole epoch, frequency by frequency.…”

Section: Eeg Recording and Preprocessingmentioning

confidence: 99%

Dynamics of alpha suppression index both modality specific and general attention processes

Clements

Gyurkovics

Low

et al. 2022

Preprint

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EEG alpha power varies under many circumstances requiring visual attention. However, mounting evidence indicates that alpha may not only serve visual processing, but also the processing of stimuli presented in other sensory modalities, including hearing. We previously showed that alpha dynamics during an auditory task vary as a function of competition from the visual modality (Clements et al., 2022) suggesting that alpha may be engaged in multimodal processing. Here we assessed the impact of allocating attention to the visual or auditory modality on alpha dynamics, during the preparatory period of a bimodal-cued conflict task. In this task, precues indicated the modality (vision, hearing) relevant to a subsequent reaction stimulus. This task afforded us the opportunity to assess alpha during modality-specific preparation and while switching between modalities. Alpha suppression following the precue occurred in all conditions indicating that it may reflect general preparatory mechanisms. However, we observed a switch effect when preparing to attend to the auditory modality, in which greater alpha suppression was elicited when switching to the auditory modality compared to repeating. No switch effect was evident when preparing to attend to visual information (although robust suppression did occur in both conditions). In addition, waning alpha suppression preceded error trials, irrespective of sensory modality. These findings indicate that alpha can be used to monitor the level of preparatory attention to process both visual and auditory information. These results support the emerging view that alpha band activity may index a general attention control mechanism used across modalities, at least vision and hearing.

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