Neural bases of emotional processing in pediatric bipolar disorder.

UNLABELLED: Pediatric bipolar disorder (PBD) presents with severe affect dysregulation characterized by elated mood, irritability and depressive symptoms, often in the form of a mixed episode. Early recognition of the external clinical features and the underlying emotional processing circuitry will help us understand the neurobiological underpinnings of this disorder and offer innovative ideas for early intervention.

METHODS: A 5-year review was conducted in structural and functional imaging studies in PBD that are potentially relevant to the emotional processing in PBD.

RESULTS: The ventral frontolimbic circuitry and the dorsal frontostriatal circuitry appear to be involved in affect regulation, with the ventral circuitry being more directly involved in emotion processing. The associated and interlinked circuits include the facial emotion-processing circuit and the association circuit between the occipital and the limbic regions responsible for automatic processing of emotions.

CONCLUSION: While we are at a preliminary stage in understanding the neural circuitry behind emotional processing, there appears to be a top-down regulation of affect with prefrontal systems modulating subcortical structures such as the amygdala and the ventral striatum. Structural and connectivity studies support the functional studies findings, providing a cogent model for understanding emotion-processing circuits involving corticosubcortical neural systems. Functional studies with PBD patients are beginning to demonstrate the dysfunction in the affective and cognitive circuits that work in concert.