Alpha and SSVEP power outperform gamma power in capturing attentional modulation in human EEG

Das, A and Nandi, N and Ray, S (2024) Alpha and SSVEP power outperform gamma power in capturing attentional modulation in human EEG. In: Cerebral Cortex, 34 (1).

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Abstract

Attention typically reduces power in the alpha (8-12 Hz) band and increases power in gamma (>30 Hz) band in brain signals, as reported in macaque local field potential (LFP) and human electro/magneto-encephalogram (EEG/MEG) studies. In addition, EEG studies often use flickering stimuli that produce a specific measure called steady-state-visually-evoked-potential (SSVEP), whose power also increases with attention. However, effectiveness of these neural measures in capturing attentional modulation is unknown since stimuli and task paradigms vary widely across studies. In a recent macaque study, attentional modulation was more salient in the gamma band of the LFP, compared to alpha or SSVEP. To compare this with human EEG, we designed an orientation change detection task where we presented both static and counterphasing stimuli of matched difficulty levels to 26 subjects and compared attentional modulation of various measures under similar conditions. We report two main results. First, attentional modulation was comparable for SSVEP and alpha. Second, non-foveal stimuli produced weak gamma despite various stimulus optimizations and showed negligible attentional modulation although full-screen gratings showed robust gamma activity. Our results are useful for brain-machine-interfacing studies where suitable features are used for decoding attention, and also provide clues about spatial scales of neural mechanisms underlying attention. © 2023 The Author(s). Published by Oxford University Press. All rights reserved.

Item Type:	Journal Article
Publication:	Cerebral Cortex
Publisher:	Oxford University Press
Additional Information:	The copyright for this article belongs to Author.
Department/Centre:	Division of Biological Sciences > Centre for Neuroscience
Date Deposited:	01 Mar 2024 07:25
Last Modified:	01 Mar 2024 07:25
URI:	https://eprints.iisc.ac.in/id/eprint/83954

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