Across-subjects classification of stimulus modality from human MEG high frequency activity.

Single-trial analyses have the potential to uncover meaningful brain dynamics that are obscured when averaging across trials. However, low signal-to-noise ratio (SNR) can impede the use of single-trial analyses and decoding methods. In this study, we investigate the applicability of a single-trial a...

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Main Authors: Britta U Westner, Sarang S Dalal, Simon Hanslmayr, Tobias Staudigl
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2018-03-01
Series:PLoS Computational Biology
Online Access:http://europepmc.org/articles/PMC5864083?pdf=render
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author Britta U Westner
Sarang S Dalal
Simon Hanslmayr
Tobias Staudigl
author_facet Britta U Westner
Sarang S Dalal
Simon Hanslmayr
Tobias Staudigl
author_sort Britta U Westner
collection DOAJ
description Single-trial analyses have the potential to uncover meaningful brain dynamics that are obscured when averaging across trials. However, low signal-to-noise ratio (SNR) can impede the use of single-trial analyses and decoding methods. In this study, we investigate the applicability of a single-trial approach to decode stimulus modality from magnetoencephalographic (MEG) high frequency activity. In order to classify the auditory versus visual presentation of words, we combine beamformer source reconstruction with the random forest classification method. To enable group level inference, the classification is embedded in an across-subjects framework. We show that single-trial gamma SNR allows for good classification performance (accuracy across subjects: 66.44%). This implies that the characteristics of high frequency activity have a high consistency across trials and subjects. The random forest classifier assigned informational value to activity in both auditory and visual cortex with high spatial specificity. Across time, gamma power was most informative during stimulus presentation. Among all frequency bands, the 75 Hz to 95 Hz band was the most informative frequency band in visual as well as in auditory areas. Especially in visual areas, a broad range of gamma frequencies (55 Hz to 125 Hz) contributed to the successful classification. Thus, we demonstrate the feasibility of single-trial approaches for decoding the stimulus modality across subjects from high frequency activity and describe the discriminative gamma activity in time, frequency, and space.
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spelling doaj.art-8371868a1fb549a5ae1bb00d27f96cf72022-12-21T19:08:44ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582018-03-01143e100593810.1371/journal.pcbi.1005938Across-subjects classification of stimulus modality from human MEG high frequency activity.Britta U WestnerSarang S DalalSimon HanslmayrTobias StaudiglSingle-trial analyses have the potential to uncover meaningful brain dynamics that are obscured when averaging across trials. However, low signal-to-noise ratio (SNR) can impede the use of single-trial analyses and decoding methods. In this study, we investigate the applicability of a single-trial approach to decode stimulus modality from magnetoencephalographic (MEG) high frequency activity. In order to classify the auditory versus visual presentation of words, we combine beamformer source reconstruction with the random forest classification method. To enable group level inference, the classification is embedded in an across-subjects framework. We show that single-trial gamma SNR allows for good classification performance (accuracy across subjects: 66.44%). This implies that the characteristics of high frequency activity have a high consistency across trials and subjects. The random forest classifier assigned informational value to activity in both auditory and visual cortex with high spatial specificity. Across time, gamma power was most informative during stimulus presentation. Among all frequency bands, the 75 Hz to 95 Hz band was the most informative frequency band in visual as well as in auditory areas. Especially in visual areas, a broad range of gamma frequencies (55 Hz to 125 Hz) contributed to the successful classification. Thus, we demonstrate the feasibility of single-trial approaches for decoding the stimulus modality across subjects from high frequency activity and describe the discriminative gamma activity in time, frequency, and space.http://europepmc.org/articles/PMC5864083?pdf=render
spellingShingle Britta U Westner
Sarang S Dalal
Simon Hanslmayr
Tobias Staudigl
Across-subjects classification of stimulus modality from human MEG high frequency activity.
PLoS Computational Biology
title Across-subjects classification of stimulus modality from human MEG high frequency activity.
title_full Across-subjects classification of stimulus modality from human MEG high frequency activity.
title_fullStr Across-subjects classification of stimulus modality from human MEG high frequency activity.
title_full_unstemmed Across-subjects classification of stimulus modality from human MEG high frequency activity.
title_short Across-subjects classification of stimulus modality from human MEG high frequency activity.
title_sort across subjects classification of stimulus modality from human meg high frequency activity
url http://europepmc.org/articles/PMC5864083?pdf=render
work_keys_str_mv AT brittauwestner acrosssubjectsclassificationofstimulusmodalityfromhumanmeghighfrequencyactivity
AT sarangsdalal acrosssubjectsclassificationofstimulusmodalityfromhumanmeghighfrequencyactivity
AT simonhanslmayr acrosssubjectsclassificationofstimulusmodalityfromhumanmeghighfrequencyactivity
AT tobiasstaudigl acrosssubjectsclassificationofstimulusmodalityfromhumanmeghighfrequencyactivity