Attentional bias modification is associated with fMRI response towards negative stimuli in individuals with residual depression: a randomized controlled trial

Background: Attentional bias modification (ABM) may lead to more adaptive emotion perception and emotion regulation. Understanding the neural basis of these effects may lead to greater precision for future treatment development. Task-related functional magnetic resonance imaging (fMRI) following ABM training has so far not been investigated in depression. The main aim of this randomized controlled trial (RCT) was to explore differences in brain activity after ABM training in response to emotional stimuli. Methods: A total of 134 previously depressed individuals who had been treated for depression and had various degrees of residual symptoms, were randomized into 14 days of active ABMor a closely matched placebo training followed by an fMRI emotion regulation task. The training procedure was a classical dot-probe task with emotional face stimuli. In the active ABM condition the probes replaced the more positively valenced face of a given pair. As participants implicitly learned to predict the probe location this should induce a more positive attentional bias (AB). The placebo condition was identical, except the contingency of the probe which appeared equally often behind positive and negative stimuli. Depression symptoms and subjective ratings of perceived negativity during fMRI was examined between the training groups. Brain activation was explored within predefined regions of interest (ROI) and across the whole brain. Activation in areas associated with changes in AB and degree of depression was explored. Results: The ABM group showed reduced activation within the amygdala and within the anterior cingulate cortex (ACC) when passively viewing negative images compared to the placebo group. No group differences were found within predefined ROI’s associated with emotion regulation strategies. Response within the temporal cortices was associated with degree of change in AB and with degree of depressive symptoms in ABM versus placebo. Limitations: The findings should be replicated in other samples of depressed patients and in studies using fMRI designs that allow analyses of within-group variability from baseline to follow-up. Conclusions: BM training has an effect on brain function within circuitry associated with emotional appraisal and the generation of affective states. Clinicaltrials.gov identifier: NCT02931487