Virtual Reality Reward Training and Transcranial Magnetic Stimulation for Depression

Anhedonia is a core feature of major depressive disorder (MDD) (DSM-5). Functional magnetic resonance imaging (fMRI) studies have associated anhedonia in MDD with altered frontostriatal activity and functional connectivity relative to controls. Conversely, antidepressant treatment is associated with increased ability for patients with MDD to sustain frontostriatal activity in a manner predictive of decrease in anhedonia and gains in daily positive affect. Novel interventions are needed to address anhedonia. Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) has been shown to activate striatal reward circuits. Positive Affect Treatment (PAT) was developed to treat deficits in reward processing; a critical skill patients are trained on in PAT involves recounting and savouring of positive experiences. However, amotivation impedes some patients from engaging in positive activities, prompting the development of virtual reality reward training (VR RT) for this skill. Evidence is building that brain state at the time of rTMS impacts its therapeutic effect. For example, imaginal exposure and individualized symptom provocation just prior to rTMS enhances its therapeutic effect on post-traumatic stress disorder and obsessive-compulsive disorder, respectively. It is unknown whether VR RT can augment rTMS for MDD and if so whether it is mediated by enhancing changes in frontostriatal activity or functional connectivity.

The current study is significant for multiple reasons. As mentioned, there is a paucity of effective treatments for anhedonia and this study may inform development of a novel treatment strategy that harnesses findings from affective neuroscience. Recent economic analysis suggests that rTMS can be more cost-effective than pharmacotherapy or ECT for treatment-resistant depression (Ontario Health, 2021). Our findings will provide insight on ways to synergize specific psychotherapeutic techniques with targeted stimulation of brain circuits to more effectively treat subtypes of depression.