Background
In participants with major depressive disorder(MDD) trained to upregulate their amygdala hemodynamic response during positive autobiographical memory recall with real-time fMRI neurofeedback(rtfMRI-nf) training, depressive symptoms diminish. This study tested whether amygdala rtfMRI-nf also changes emotional processing of positive and negative stimuli in a variety of behavioral and imaging tasks.
Method
Patients with MDD completed two rtfMRI-nf sessions(18 received amygdala rtfMRI-nf, 16 received control parietal rtfMRI-nf). One week prior-to and following rtfMRI-nf training participants performed tasks measuring responses to emotionally valenced stimuli including a backward masking task(BMT), which measures the amygdala hemodynamic response to emotional faces presented for traditionally subliminal duration and followed by a mask, and the Emotional Test Battery(ETB) in which reaction times and performance accuracy are measured during tasks involving emotional faces and words.
Results
During the BMT, amygdala responses increased while viewing masked happy faces, but decreased to masked sad faces in the experimental versus control group following rtfMRI-nf. During the ETB, reaction times decreased to identification of positive faces and during self-identification with positive words, and vigilance scores increased to positive faces and decreased to negative faces during the face dot-probe task in the experimental versus control group following rtfMRI-nf.
Conclusions
rtfMRI-nf training to increase the amygdala hemodynamic response to positive memories was associated with changes in amygdala responses to happy and sad faces and improved processing of positive stimuli during performance of the ETB. These results may suggest that amygdala rtfMRI-nf training alters responses to emotional stimuli in a manner similar to antidepressant pharmacotherapy.