Functional neural plasticity after compassion-based interventions: A scoping review of longitudinal neuroimaging...

Compassion-based interventions (CBIs) have been suggested as an add-on treatment to cognitive therapy in patients struggling to experience positive affect, for instance, patients with major depressive disorder. Identifying neural changes during CBIs could reveal action mechanisms beneficial for their treatment. We therefore summarize evidence regarding the neural changes after CBIs in longitudinal functional magnetic resonance imaging studies.

According to PRISMA guidelines, the literature was screened via Web of Science Core Collection in December 2022. Twelve studies were checked for eligibility following PICOS criteria: longitudinal task-based fMRI-studies investigating neural changes associated with CBIs. We included eight studies with three studies reporting overlapping populations, yielding N = 441 participants (n(CBI) = 283, n(control) = 158), double sampling excluded.

CBIs were convergently associated with increased activity in prefrontal and mesolimbic brain regions and altered posterior parietal and occipital activity across included studies. Additional to these concordant findings, individual studies found increased fronto-striatal connectivity, and functional alterations in other brain regions such as temporal cortex, cerebellum or insula.

Our review points to interesting action mechanisms of CBIs corroborating previous cross-sectional evidence from fMRI studies. Increased mesolimbic activity and fronto-striatal connectivity imply upregulation of positive affect and reward-experience as putative mechanism of action, while occipital functional changes could suggest improved visual engagement in distressful stimuli. Alterations in prefronto-parietal activity indicate attention and cognitive control changes after CBIs. Hence, our review suggests a tentative neurobiological synthesis of evidence for the efficacy of CBIs in augmenting positive affect, thereby preliminarily underpinning its proposed potential as adjunctive psychotherapeutic treatment.