Subjective regulation success mediates the influence of neurofeedback performance on mood in the absence of training effects.

Background: Functional magnetic resonance imaging neurofeedback (fMRI NF) is gaining popularity as an experimental treatment for psychiatric and neurologic disorders. However, concerns that fMRI NF acts as a placebo rather than through operant conditioning principles, as known for electroencephalography NF, have largely been disregarded. Methods: To examine these concerns, 25 healthy individuals underwent training to downregulate activity in the amygdala and subgenual anterior cingulate cortex, and to upregulate both regions concurrently as a bidirectional control condition, across six sessions in a randomized, single-blind, within-subject design. Results: While we found no consistent changes in brain activation or training effects across participants, subjective ratings of regulation success mediated the effect of brain activation and objectively achieved regulation on mood changes for both brain regions and regulation directions. Quantified emotional valence and arousal of the regulation strategies had no detectable influence at any stage. Conclusion: Our findings suggest predominantly non-specific effects of fMRI NF on mood changes in healthy individuals, which are mediated by the impression of subjective regulation success-at least in the absence of training effects. While the results partially support concerns about the specificity of fMRI NF, further research is required to determine how these findings generalize across different training protocols and patient populations.