Abnormal Corpus Callosum Integrity in Bipolar Disorder: A Diffusion Tensor Imaging Study

Objective: Abnormalities in the anterior interhemispheric connections provided by the corpus callosum (CC) have long been implicated in bipolar disorder (BID). In this study, we used complementary diffusion tensor imaging methods to study the structural integrity of the CC and localization of potential abnormalities in BD. Methods: Subjects included 33 participants with BID and 40 healthy comparison participants. Fractional anisotropy (FA) measures were compared between groups with region of interest (ROD methods to investigate the anterior, middle, and posterior CC and voxel-based methods to further localize abnormalities. Results: In ROI-based analyses, FA was significantly decreased in the anterior and middle CC in the BID group (p <.05). Voxel-based analyses similarly localized group differences to the genu, rostral body, and anterior midbody of CC (p <.05, corrected). Conclusion: The findings demonstrate abnormalities in the structural integrity of the anterior CC in BID that might contribute to altered interhemispheric connectivity in this disorder.National Institute of Mental Health (NIH)National Institute of Mental Health (NIH)[R01MH69747]National Institute of Mental Health (NIH)National Institute of Mental Health (NIH)[R01MH070902]National Institute of Mental Health (NIH)National Institute of Mental Health (NIH)[T32MH14276]National Institute of Mental Health (NIH)National Institute of Mental Health (NIH)[R01 EB006494]National Institute of Mental Health (NIH)[K23MH077914]National Institute of Mental Health (NIH)The Department of Veterans Affairs Career DevelopmentThe Department of Veterans Affairs Career DevelopmentMerit ReviewMerit ReviewResearch Enhancement Award Program (REAP)Research Enhancement Award Program (REAP)Attias Family FoundationAttias Family FoundationMarcia Simon KaplanMarcia Simon KaplanKlingenstein FoundationKlingenstein FoundationAlational InstitutesAlational InstitutesHealth (NIH)/National Center for Research Resources/Clinical and Translational Science AwardsHealth (NIH)/National Center for Research Resources/Clinical and Translational Science Awards[UL1RR024139-01]NIH/National Institute of Biomedical Imaging and Bioengineering[R01 EB006494]NIH/National Institute of Biomedical Imaging and Bioengineerin

Functional and Structural Connectivity Between the Perigenual Anterior Cingulate and Amygdala in Bipolar Disorder

Objective: Abnormalities in the morphology and function of two gray matter structures central to emotional processing, the perigenual anterior cingulate cortex (pACC) and amygdala, have consistently been reported in bipolar disorder (BD). Evidence implicates abnormalities in their connectivity in BD. This study investigates the potential disruptions in pACC-amygdala functional connectivity and associated abnormalities in white matter that provides structural connections between the two brain regions in BD. Methods: Thirty-three individuals with BD and 31 healthy comparison subjects (HC) participated in a scanning session during which functional magnetic resonance imaging (fMRI) during processing of face stimuli and diffusion tensor imaging (DTI) were performed. The strength of pACC-amygdala functional connections was compared between BD and HC groups, and associations between these functional connectivity measures from the fMRI scans and regional fractional anisotropy (FA) from the DTI scans were assessed. Results: Functional connectivity was decreased between the pACC and amygdala in the BD group compared with HC group, during the processing of fearful and happy faces (p < .005). Moreover, a significant positive association between pACC-amygdala functional coupling and FA in ventrofrontal white matter, including the region of the uncinate fasciculus, was identified (p < .005). Conclusion: This study provides evidence for abnormalities in pACC-amygdala functional connectivity during emotional processing in BD. The significant association between pACC-amygdala functional connectivity and the structural integrity of white matter that contains pACC-amygdala connections suggest that disruptions in white matter connectivity may contribute to disturbances in the coordinated responses of the pACC and amygdala during emotional processing in BD.National Institute of Mental Health (NIH)[R01MH69747]National Institute of Mental Health (NIH)National Institute of Mental Health (NIH)National Institute of Mental Health (NIH)[R01MH070902]National Institute of Mental Health (NIH)[T32MH1427G]National Institute of Mental Health (NIH)Clinical and Translational Science Award (CTSA), NIH National Center[UL1 RR0249139]Clinical and Translational Science Award (CTSA), NIH National CenterDepartment of Veterans Affairs Career Development (HPB), Merit Review (HPB) and Research Enhancement Award Program (REAP)Department of Veterans Affairs Career Development (HPB), Merit Review (HPB) and Research Enhancement Award Program (REAP)National Alliance for Research in Schizophrenia and Depression (Great Neck, New York)National Alliance for Research in Schizophrenia and Depression (Great Neck, New York)Attias Family FoundationAttias Family FoundationMarcia Simon KaplanMarcia Simon KaplanEthel F. Donaghzre Women`s Investigator ProgramEthel F. Donaghzre Women`s Investigator ProgramKlingenstein FoundationKlingenstein FoundationHoward Hughes Medical Institute FellowshipHoward Hughes Medical Institute Fellowshi