Impaired social learning predicts reduced real-life motivation in individuals with depression: A computational fMRI study

Abstract

Background: Major depressive disorder is associated with altered social functioning and impaired learning, on both the behavioural and the neural level. These deficits are likely related, considering that successful social interactions require learning to predict other people's emotional responses. Yet, there is little research examining this relation.Methods: Forty-three individuals with high (HD; N=21) and low (LD; N=22) depression scores answered questions regarding their real-life social experiences and performed a social learning task during fMRI scanning. As part of the task, subjects learned associations between name cues and rewarding (happy faces) or aversive (fearful faces) social outcomes. Using computational modelling, behavioural and neural correlates of social learning were examined and related to real-life social experiences.Results: HD participants reported reduced motivation to engage in real-life social activities and demonstrated elevated uncertainty about social outcomes in the task. Moreover, HD subjects displayed altered encoding of social reward predictions in the insula, temporal lobe and parietal lobe. Interestingly, across all subjects, higher task uncertainty and reduced parietal prediction encoding were associated with decreased motivation to engage in real-life social activities. Limitations:The size of the included sample was relatively small. The results should thus be regarded as preliminary and replications in larger samples are called for. Conclusion:Taken together, our findings suggest that reduced learning from social outcomes may impair depressed individuals' ability to predict other people's responses in real life, which renders social situations uncertain. This uncertainty, in turn, may contribute to reduced social engagement (motivation) in depression.

Effects of serotonin and dopamine depletion on neural prediction computations during social learning

“…These results are in line with previous reports of decreased non-social learning after reductions in 5-HT functioning [23][24][25][26]. Interestingly, using the same task, we previously observed very similar results in individuals with high depression scores [2], which suggests that low levels of 5-HT may contribute to social learning deficits in depression.…”

“…This interpretation is, of course, speculative and more direct assessments of this hypothesized effect, and the role of the different brain regions, are needed. Yet, it is interesting to note that, using the same task, we previously found a similar pattern of reversed social reward prediction encoding in the insula and temporal lobe of individuals with high depression scores [2]. Taken together, these findings suggest that low levels of 5-HT may contribute to impaired social reward learning in depression by biasing learning towards negatively perceived ambiguous stimuli.…”

“…We have previously shown that impaired social learning is associated with diminished social engagement motivation and more frequent experiences of negative interpersonal encounters in everyday life [1,2]. These findings are particularly relevant to the understanding of social impairments in major depressive disorder, as depressed individuals demonstrate reduced learning from social feedback, as well as altered neural encoding of social learning signals [1,2].…”

Effects of Serotonin and Dopamine Depletion on Neural Prediction Computations during Social Learning

“…These results are in line with previous reports of decreased non-social learning after reductions in 5-HT functioning [23][24][25][26]. Interestingly, using the same task, we previously observed very similar results in individuals with high depression scores [2], which suggests that low levels of 5-HT may contribute to social learning deficits in depression.…”

“…This may have made the latter more salient, resulting in the recruitment of attentional and working memory processes to support the prediction of neural faces. Interestingly, using the same task, we previously found a similar pattern of reversed social reward prediction encoding in the insula and temporal lobe of individuals with high depression scores [2].…”