We report a study of emotion self-regulation training in patients with major depressive disorder (MDD) using simultaneous real-time fMRI and EEG neurofeedback (rtfMRI-EEG-nf). Emotion-relevant target nf measures included fMRI activities of the left amygdala and left rACC, and frontal EEG asymmetries in the alpha and high-beta bands. MDD patients successfully learned to upregulate all four measures simultaneously using rtfMRI-EEG-nf during a happy emotion induction task. EEG-fMRI data analyses provided new insights into mechanisms of rtfMRI-EEG-nf. These findings may lead to development of more efficient neurotherapies for MDD.
Twenty four unmedicated MDD patients completed the study. Technical details of the rtfMRI-EEG-nf implementation and experimental procedure were described previously4. The experiments were performed on a GE MR750 3T MRI scanner with an 8-channel head coil. A gradient-echo EPI sequence with FOV/slice=240/2.9 mm, TR/TE=2000/30 ms, SENSE R=2, image matrix 96×96, flip=90°, 34 axial slices, was employed for fMRI. Simultaneous EEG recordings were performed using a 32-channel MR-compatible EEG system (Brain Products GmbH) with 0.1 µV resolution and 5 kS/s sampling, relative to FCz reference.
The rtfMRI-EEG-nf (Fig. 1A) was implemented using a custom multimodal real-time system1. The two rtfMRI-nf signals (red, orange bars) were based, respectively, on fMRI activations for the LA and left rACC ROIs (Fig. 1B). The two EEG-nf signals (purple, magenta bars) were based, respectively, on frontal EEG asymmetry changes in the high-beta (beta3) band, [21…30] Hz, and in the alpha band [7.5…12.5] Hz, for channels F3 and F4 (Fig. 1C). Real-time relative alpha asymmetry was defined as A = (P(F4)−P(F3))/(P(F4)+P(F3)), where P is EEG power in the alpha band. Real-time relative high-beta asymmetry was defined as B = (P(F3)−P(F4))/(P(F3)+P(F4)), where P is EEG power in the high-beta band. A custom procedure for improved real-time removal of EEG-fMRI artifacts (Fig. 1E) was implemented in BrainVision RecView software and employed a specially modified MR-compatible EEG cap4. The four nf bars were updated every 2 s.
The experimental protocol (Fig. 1D) included six runs, and each run (except Rest) consisted of 40-s-long blocks of Rest, Happy Memories, and Count conditions9-11. For each Happy Memories condition, the participant was asked to feel happy by evoking happy autobiographical memories, while trying to raise the levels of all four nf bars to the fixed target level (horizontal bar in Fig. 1A), which was raised from run to run. No nf bars were displayed during the Rest and Count conditions, and during the entire Transfer run.
Offline fMRI data analyses were performed in AFNI12, and EEG analyses – in BrainVision Analyzer 2. Normalized asymmetry for the alpha band was defined as FAA = ln(P(F4))−ln(P(F3)), where P is EEG power in the individual upper alpha band11. Normalized asymmetry for the high-beta band was defined as FBA = ln(P(F3))−ln(P(F4)). EEG-informed psychophysiological interaction (PPI)13 analyses were conducted using fMRI regressors based on FAA and FBA time courses1,11.
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