King's College London

The research, published in Social, Cognitive and Affective Neuroscience, scanned the brains of adolescents with and without depression whilst they were watching a 10 minute clip of the movie ‘Despicable Me’.

The findings suggest that, even though many depressed adolescents experience a sense of emotional numbing or blunting, their brains may actually be working harder to interpret information about how others are feeling and thinking and responding to situations. In addition, this ‘over-working’ of the brain appears to happen more at times when there are fewer cues about how a character is feeling or thinking.

While previous research has explored emotional processing in depressed brains, these studies have been on small samples, used static stimuli/images and did not track how brain activity continuously evolves over time. These limitations have made it difficult to establish how attention and emotions interact over time.

Drawing from a large publicly available sample¹, the researchers identified 84 adolescents aged 16-21 (42 who had been clinically diagnosed with depression vs 42 non-depressed controls). Participants watched a 10-minute clip of the movie ‘Despicable Me’ while undergoing an MRI scan. The clip alternated between highly emotional and emotionally neutral scenes.

The researchers found distinct differences between the two groups of participants in the way that their brains processed the movie. The depressed group over-used the Dorsal Attention Network – which is thought to voluntarily allocate attention to external stimuli – and under-recruited the Ventral Attention Network – which is known for automatically responding to unexpected cues in the environment, such as loud noises or sudden changes in facial expressions. This pattern of activity was more pronounced during scenes that were relatively neutral.

Dr Owen O’Daly, a Senior Lecturer in Neuroimaging at King’s IoPPN and the study’s last author said, “Psychiatric conditions that often occur alongside depression are important factors to consider in studies on social-emotional processing in adolescents. By matching the control participants based on their psychiatric diagnoses, we can be more confident that the differences we observed in brain circuits between groups can be specifically attributed to depression. Furthermore, our results support our previous findings revealing similar changes in the same brain circuits in healthy participants who experience a lack of pleasure (anhedonia). In that study, the unusual brain activity was mainly observed when listening to neutral music played after a sad song, further suggesting a specific link to depressive symptoms.”

This study was possible thanks to data provided by the Child Mind Institute as part of the Healthy Brain Network biobank, and support from the National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre (BRC).

 

Atypical attentional network dynamics in adolescent depression during emotional movie viewing (DOI10.1093/scan/nsaf011) (Marie-Stephanie Cahart, Vincent Giampietro, Owen O’Daly) was published in Social, Cognitive and Affective Neuroscience.

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