Corpus callosal morphology in youth with bipolar depression

MacMaster FP, Langevin LM, Jaworska N, Kemp A, Sembo M.Corpus callosal morphology in youth with bipolar depression.Bipolar Disord 2014: 16: 889–893. © 2014 John Wiley & Sons A/S.Published by John Wiley & Sons Ltd.Objectives: Recent evidence has demonstrated that corpus callosummaturation follows a similar developmental timeline to cognitiveprocesses. Bipolar disorder (BD) has been associated with disruptions inerror processing, response inhibition, and motor functioning, which aremediated by underlying white matter structures, including the corpuscallosum. Disruptions in white matter integrity have been demonstratedin BD. However, it is unknown whether alterations in the developmentaltrajectory of the corpus callosum may contribute to cognitiveimpairments in the disorder.Methods: We assessed the area of the corpus callosum and its subregions(the genu, rostral body, anterior and posterior bodies, isthmus, andsplenium) in 14 treatment-na€ive adolescents with BD (<21 years of ageand in the depressed phase) and 18 healthy adolescent controls.Results: In comparison with healthy controls, participants with BDdemonstrated a significantly reduced overall corpus callosum area. Wealso noted smaller areas in the anterior and posterior mid-body of thecorpus callosum in adolescents with BD.Conclusions: Our results suggest that commissural fibers of the corpuscallosum are disrupted in early-onset BD. Specific decreases in theanterior and posterior mid-body callosal aspects may contribute tomotor organization and inhibition deficits seen in BD. These findings areconsistent with the involvement of inter-hemispheric tracts in early-onsetBD, which may reflect an early deviation in white matter development.