Brain response to emotion altered in BD youth

By Mark Cowen

Results from a US study show that adolescents with bipolar disorder (BD) have altered activation in certain brain regions in response to facial expressions of emotion.

Furthermore, the researchers found that adolescents with the mood disorder exhibited problems processing and/or disengaging attention from facial expressions of emotion compared with their mentally healthy peers.

The findings come from a study of 20 euthymic adolescents with BD who were aged 9-17 years and had a family history of the mood disorder and 21 mentally healthy adolescents without such a family history. There were no significant between-group differences regarding mean age, gender distribution, or IQ.

All of the participants underwent functional magnetic resonance imaging of the brain while viewing happy, sad, or neutral facial expressions.

Overall, there were no significant differences between adolescents with BD and controls regarding task performance, although BD patients showed a trend for reduced accuracy when identifying the gender of the happy and sad faces.

However, adolescents with BD exhibited significantly reduced activation in the dorsolateral prefrontal cortex and significantly increased amygdala/hippocampal activation while viewing facial expressions of emotion compared with controls.

Furthermore, adolescents with BD showed increasing levels of activation in the superior temporal sulcus/insula and visual cortex between the early and late phases of exposure to each block of facial expressions.

By contrast, activation in these areas fell slightly among controls between the early and late phases of exposure.

This suggests that mentally healthy individuals efficiently process emotional faces and then decrease allocation of neural resources, whereas BD patients have a gradually increasing response to faces, "possibly reflecting difficulty processing emotional facial expressions," comment Amy Garrett (Stanford University School of Medicine, California) and team.

They conclude in the Journal of the American Academy of Child and Adolescent Psychiatry: "Our findings support models of deficient prefrontal and excessive amygdala activation in patients with BD compared with healthy controls, and add new information suggesting that youth with BD have aberrant timing of superior temporal sulcus and visual cortical activation to facial expressions."

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