Enhancing Emotion Regulation Through Functional Near-infrared Spectroscopy (fNIRS)-Informed Real-time Neurofeedback

The prevalence of stress-related disorders such as major depression and anxiety disorders has increased among children, adolescents and young adults internationally. Despite increasing concerns about the tremendous personal and societal toll of this development, efficacious interventions to reduce the detrimental impact of stress in young individuals are lacking. Therefore, working towards developing innovative approaches for regulating negative emotional experiences has substantial implications for addressing the prevailing mental health challenges affecting communities on a local and global scale.

Neurofeedback is a promising non-invasive neuromodulation technique allowing individuals to rapidly learn volitional control over brain activity via providing real-time feedback on brain function. Initial studies suggest that neurofeedback for emotion regulation produces increased experiences of positive emotion in patients with depression and decreased anxious mood in patients with anxiety disorder. A limitation of existing studies, however, is that neurofeedback training is often not directed with a concrete strategy that can help participants better learn control over brain activity, and extend learning outside of the experimental context.

Cognitive reappraisal, an emotion regulation strategy that focuses on reevaluating and changing the interpretation of an aversive scene or stimulus to reduce its negative impact on an individuals' emotions, has been implemented in several neurofeedback studies. It is shown to be effective in reducing negative emotions in clinical populations, such as in depression, anxiety, and trauma disorders when combined with fMRI neurofeedback. Meta-analytic evidence points to the lateral prefrontal cortex (lPFC) as a common region active during cognitive reappraisal. Thus, lPFC regions are a promising target for emotion regulation that has otherwise not been a target in existing studies, which traditionally focus on modulating emotional reactivity via subcortical regions.

Nevertheless, the implementation of neurofeedback-guided training on cortical level regions is relatively scarce, and even more so for improving emotion regulation in non-clinical populations. In our own previous studies, it has been previously demonstrated that healthy subjects can learn to control the activity of brain regions involved in emotional processing and that this can reduce anxiety. This suggests there is a promising potential of fNIRS neurofeedback training in combination with cognitive reappraisal strategies as a novel approach with broader implications for regulating stress in both clinical and non-clinical populations.

The present study aims to employ real-time fNIRS neurofeedback training in combination with cognitive reappraisal strategies for regulating negative emotions in healthy individuals. Participants will undergo cognitive reappraisal training with either real neurofeedback or sham feedback. Furthermore, emotion regulation ability will be assessed prior to and after neurofeedback training, through pre- and post-test behavioral measures and from comparing performance between real neurofeedback and sham feedback groups on a post-training task inducing physiological stress.

Participants will be explicitly instructed to apply cognitive reappraisal to upregulate brain activity. Prior to the neurofeedback runs, they will receive training illustrating the concept of cognitive reappraisal and neural basis of emotion regulation.

The present study will apply double-blinding. Participants will complete the experiment without knowing the presence of a control condition. The instructions administered to both groups will be exactly the same, and the experimenter responsible for administering instructions to the participant will not be aware of the participant's assigned group.

Inclusion criteria

• Normal/corrected-to-normal vision
• Right-handed
• Below the cut-off for clinically-significant levels of depression (below 29) indicated by the Beck Depression Inventory (BDI-II; Beck et al., 1996)

Exclusion criteria

• Current/history of mental health conditions
• Current/history of chronic pain
• The following conditions: Cardiovascular disorder, Raynaud's phenomenon, fainting, seizure, wounds on the hand/arm
• Frequent use of alcohol/nicotine