Abnormally increased effective connectivity between parahippocampal gyrus and ventromedial prefrontal regions during emotion labeling in bipolar disorder

• Published in: Psychiatry research. Neuroimaging Vol. 174; no. 3; pp. 195 - 201
• Main Authors: Almeida, Jorge R.C., Mechelli, Andrea, Hassel, Stefanie, Versace, Amelia, Kupfer, David J., Phillips, Mary L.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 30.12.2009; Elsevier
• Subjects: Adult; Adult and adolescent clinical studies; Bayes Theorem; Biological and medical sciences; Bipolar disorder; Bipolar Disorder - pathology; Bipolar Disorder - physiopathology; Bipolar disorders; Brain Mapping; Case-Control Studies; Dynamic causal modeling; Effective connectivity; Emotion regulation; Emotions - physiology; Female; fMRI; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Medical sciences; Models, Statistical; Mood disorders; Neural Pathways; Neuroimaging; Neuropsychological Tests; Nonlinear Dynamics; Oxygen; Parahippocampal Gyrus - blood supply; Parahippocampal Gyrus - physiopathology; Prefrontal Cortex - blood supply; Prefrontal Cortex - physiopathology; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Radiology; Young Adult; Neuroimaging; fMRI; Bipolar disorder; Dynamic causal modeling; Emotion regulation; Effective connectivity; Mood disorder; Human; Affect affectivity; Central nervous system; ParahIppocampal cortex; Labelling; Emotion emotionality; Prefrontal cortex; Nuclear magnetic resonance imaging; Encephalon; Medical imagery; Self regulation; Causality; Functional imaging
• DOI: 10.1016/j.pscychresns.2009.04.015
• ISSN: 0925-4927

Emotional liability and mood dysregulation characterize bipolar disorder (BD), yet no study has examined effective connectivity between parahippocampal gyrus and prefrontal cortical regions in ventromedial and dorsal/lateral neural systems subserving mood regulation in BD. Participants comprised 46 individuals (age range: 18–56 years): 21 with a DSM-IV diagnosis of BD, type I currently remitted; and 25 age- and gender-matched healthy controls (HC). Participants performed an event-related functional magnetic resonance imaging paradigm, viewing mild and intense happy and neutral faces. We employed dynamic causal modeling (DCM) to identify significant alterations in effective connectivity between BD and HC. Bayes model selection was used to determine the best model. The right parahippocampal gyrus (PHG) and right subgenual cingulate gyrus (sgCG) were included as representative regions of the ventromedial neural system. The right dorsolateral prefrontal cortex (DLPFC) region was included as representative of the dorsal/lateral neural system. Right PHG–sgCG effective connectivity was significantly greater in BD than HC, reflecting more rapid, forward PHG–sgCG signaling in BD than HC. There was no between-group difference in sgCG–DLPFC effective connectivity. In BD, abnormally increased right PHG–sgCG effective connectivity and reduced right PHG activity to emotional stimuli suggest a dysfunctional ventromedial neural system implicated in early stimulus appraisal, encoding and automatic regulation of emotion that may represent a pathophysiological functional neural mechanism for mood dysregulation in BD.