PMID- 20421978
OWN - NLM
STAT- MEDLINE
DCOM- 20110616
LR  - 20211020
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 5
IP  - 4
DP  - 2010 Apr 22
TI  - Simultaneous EEG-fMRI during a working memory task: modulations in low and high 
      frequency bands.
PG  - e10298
LID - 10.1371/journal.pone.0010298 [doi]
LID - e10298
AB  - 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.
FAU - Michels, Lars
AU  - Michels L
AD  - Functional Neurosurgery, University Hospital Zurich, Zurich, Switzerland. 
      lars.michels@kispi.uzh.ch
FAU - Bucher, Kerstin
AU  - Bucher K
FAU - Luchinger, Rafael
AU  - Luchinger R
FAU - Klaver, Peter
AU  - Klaver P
FAU - Martin, Ernst
AU  - Martin E
FAU - Jeanmonod, Daniel
AU  - Jeanmonod D
FAU - Brandeis, Daniel
AU  - Brandeis D
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20100422
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Adult
MH  - Alpha Rhythm
MH  - Beta Rhythm
MH  - Brain Mapping
MH  - Electroencephalography/*methods
MH  - Female
MH  - Humans
MH  - Magnetic Resonance Imaging/*methods
MH  - Male
MH  - Memory, Short-Term/*physiology
MH  - Oxygen/blood
MH  - Theta Rhythm
MH  - Young Adult
PMC - PMC2858659
COIS- Competing Interests: The authors have declared that no competing interests exist.
EDAT- 2010/04/28 06:00
MHDA- 2011/06/17 06:00
PMCR- 2010/04/22
CRDT- 2010/04/28 06:00
PHST- 2010/02/18 00:00 [received]
PHST- 2010/03/23 00:00 [accepted]
PHST- 2010/04/28 06:00 [entrez]
PHST- 2010/04/28 06:00 [pubmed]
PHST- 2011/06/17 06:00 [medline]
PHST- 2010/04/22 00:00 [pmc-release]
AID - 10-PONE-RA-16404R1 [pii]
AID - 10.1371/journal.pone.0010298 [doi]
PST - epublish
SO  - PLoS One. 2010 Apr 22;5(4):e10298. doi: 10.1371/journal.pone.0010298.