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Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands
BACKGROUND: EEG studies of working memory (WM) have demonstrated load dependent frequency band modulations. FMRI studies have localized load modulated activity to the dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and posterior parietal cortex (PPC). Recently, an EEG-fMRI s...
Autores principales: | , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858659/ https://www.ncbi.nlm.nih.gov/pubmed/20421978 http://dx.doi.org/10.1371/journal.pone.0010298 |
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author | Michels, Lars Bucher, Kerstin Lüchinger, Rafael Klaver, Peter Martin, Ernst Jeanmonod, Daniel Brandeis, Daniel |
author_facet | Michels, Lars Bucher, Kerstin Lüchinger, Rafael Klaver, Peter Martin, Ernst Jeanmonod, Daniel Brandeis, Daniel |
author_sort | Michels, Lars |
collection | PubMed |
description | BACKGROUND: EEG studies of working memory (WM) have demonstrated load dependent frequency band modulations. FMRI studies have localized load modulated activity to the dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and posterior parietal cortex (PPC). Recently, an EEG-fMRI study found that low frequency band (theta and alpha) activity negatively correlated with the BOLD signal during the retention phase of a WM task. However, the coupling of higher (beta and gamma) frequencies with the BOLD signal during WM is unknown. METHODOLOGY: In 16 healthy adult subjects, we first investigated EEG-BOLD signal correlations for theta (5–7 Hz), alpha1 (8–10), alpha2 (10–12 Hz), beta1 (13–20), beta2 (20–30 Hz), and gamma (30–40 Hz) during the retention period of a WM task with set size 2 and 5. Secondly, we investigated whether load sensitive brain regions are characterised by effects that relate frequency bands to BOLD signals effects. PRINCIPAL FINDINGS: We found negative theta-BOLD signal correlations in the MPFC, PPC, and cingulate cortex (ACC and PCC). For alpha1 positive correlations with the BOLD signal were found in ACC, MPFC, and PCC; negative correlations were observed in DLPFC, PPC, and inferior frontal gyrus (IFG). Negative alpha2-BOLD signal correlations were observed in parieto-occipital regions. Beta1-BOLD signal correlations were positive in ACC and negative in precentral and superior temporal gyrus. Beta2 and gamma showed only positive correlations with BOLD, e.g., in DLPFC, MPFC (gamma) and IFG (beta2/gamma). The load analysis revealed that theta and—with one exception—beta and gamma demonstrated exclusively positive load effects, while alpha1 showed only negative effects. CONCLUSIONS: We conclude that the directions of EEG-BOLD signal correlations vary across brain regions and EEG frequency bands. In addition, some brain regions show both load sensitive BOLD and frequency band effects. Our data indicate that lower as well as higher frequency brain oscillations are linked to neurovascular processes during WM. |
format | Text |
id | pubmed-2858659 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-28586592010-04-26 Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands Michels, Lars Bucher, Kerstin Lüchinger, Rafael Klaver, Peter Martin, Ernst Jeanmonod, Daniel Brandeis, Daniel PLoS One Research Article BACKGROUND: EEG studies of working memory (WM) have demonstrated load dependent frequency band modulations. FMRI studies have localized load modulated activity to the dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and posterior parietal cortex (PPC). Recently, an EEG-fMRI study found that low frequency band (theta and alpha) activity negatively correlated with the BOLD signal during the retention phase of a WM task. However, the coupling of higher (beta and gamma) frequencies with the BOLD signal during WM is unknown. METHODOLOGY: In 16 healthy adult subjects, we first investigated EEG-BOLD signal correlations for theta (5–7 Hz), alpha1 (8–10), alpha2 (10–12 Hz), beta1 (13–20), beta2 (20–30 Hz), and gamma (30–40 Hz) during the retention period of a WM task with set size 2 and 5. Secondly, we investigated whether load sensitive brain regions are characterised by effects that relate frequency bands to BOLD signals effects. PRINCIPAL FINDINGS: We found negative theta-BOLD signal correlations in the MPFC, PPC, and cingulate cortex (ACC and PCC). For alpha1 positive correlations with the BOLD signal were found in ACC, MPFC, and PCC; negative correlations were observed in DLPFC, PPC, and inferior frontal gyrus (IFG). Negative alpha2-BOLD signal correlations were observed in parieto-occipital regions. Beta1-BOLD signal correlations were positive in ACC and negative in precentral and superior temporal gyrus. Beta2 and gamma showed only positive correlations with BOLD, e.g., in DLPFC, MPFC (gamma) and IFG (beta2/gamma). The load analysis revealed that theta and—with one exception—beta and gamma demonstrated exclusively positive load effects, while alpha1 showed only negative effects. CONCLUSIONS: We conclude that the directions of EEG-BOLD signal correlations vary across brain regions and EEG frequency bands. In addition, some brain regions show both load sensitive BOLD and frequency band effects. Our data indicate that lower as well as higher frequency brain oscillations are linked to neurovascular processes during WM. Public Library of Science 2010-04-22 /pmc/articles/PMC2858659/ /pubmed/20421978 http://dx.doi.org/10.1371/journal.pone.0010298 Text en Michels et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Michels, Lars Bucher, Kerstin Lüchinger, Rafael Klaver, Peter Martin, Ernst Jeanmonod, Daniel Brandeis, Daniel Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands |
title | Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands |
title_full | Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands |
title_fullStr | Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands |
title_full_unstemmed | Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands |
title_short | Simultaneous EEG-fMRI during a Working Memory Task: Modulations in Low and High Frequency Bands |
title_sort | simultaneous eeg-fmri during a working memory task: modulations in low and high frequency bands |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858659/ https://www.ncbi.nlm.nih.gov/pubmed/20421978 http://dx.doi.org/10.1371/journal.pone.0010298 |
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