EEG Alpha-Rhythm-Related Changes in BOLD fMRI Signal in Neurofeedback Training.

Interaction of EEG and BOLD brain activity was studied in subjects during EEG-biofeedback training course (20 sessions). Healthy male subjects aged 20-35 underwent a training course of sound-reinforced upregulation of alpha- (20 participants) or beta-activity (9 participants). Pretraining, intermediate (after 10 sessions), and post-training fMRI-EEG recordings were conducted in resting state and during the participants' attempts to upregulate the power of target EEG activity. Regression analysis was carried out on three sessions in total; the main changes in BOLD signal connected with alpha rhythm power were related to the subjects who performed alpha training "good enough" (were able to increase alpha power at least at one stage). Maximum changes in BOLD response connected with alpha rhythm power were observed in the form of deactivation at T8 lead in the right hemisphere, and at F7 in the left hemisphere, and involved middle frontal gyrus, triangular part of inferior frontal gyrus, superior temporal gyrus, parietal lobule, and insula. The identified areas correspond to the executive control network (ECN) and anterior salience network (ASN).