Correlates of alpha rhythm in functional magnetic resonance imaging and near infrared spectroscopy.
We used simultaneous electroencephalogram-functional magnetic resonance imaging (EEG-fMRI) and EEG-near infrared spectroscopy (NIRS) to investigate whether changes of the posterior EEG alpha rhythm are correlated with changes in local cerebral blood oxygenation. Cross-correlation analysis of slowly fluctuating, spontaneous rhythms in the EEG and the fMRI signal revealed an inverse relationship between alpha activity and the fMRI-blood oxygen level dependent signal in the occipital cortex. The NIRS-EEG measurements demonstrated a positive cross-correlation in occipital cortex between alpha activity and concentration changes of deoxygenated hemoglobin, which peaked at a relative shift of about 8 s. Our data suggest that alpha activity in the occipital cortex is associated with metabolic deactivation. Mapping of spontaneously synchronizing distributed neuronal networks is thus shown to be feasible.
Moosmann
Matthias
M
Department of Neurology, Charité, Humboldt University, Berlin, Germany. moosmann@charite.de
Ritter
Petra
P
Krastel
Ina
I
Brink
Andrea
A
Thees
Sebastian
S
Blankenburg
Felix
F
Taskin
Birol
B
Obrig
Hellmuth
H
Villringer
Arno
A
D000328:Adult; D000513:Alpha Rhythm; D001923:Brain Chemistry / Q000502:physiology*; D004569:Electroencephalography; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood*; D010775:Photic Stimulation; D019265:Spectroscopy, Near-Infrared
D006454:Hemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen