1. ¹INSERM, U797, Research Unit 'Neuroimaging and Psychiatry', IFR49, Orsay, France
2. ²CEA, 'Neuroimaging and Psychiatry' Unit, Hospital Department Frédéric Joliot, I2BM, Orsay, France
3. ³University Paris-Sud 11 and University Paris 5 Rene Descartes, Paris, France
4. ⁴AP-HP, Groupe Henri Mondor-Albert Chenevier, Psychiatry Department, University Paris 12, Créteil, France
5. ⁵Faculty of Medicine, University Paris 12, Créteil, France
6. ⁶Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, John Radcliffe Hospital, Headington, Oxford, UK
7. ⁷INSERM, U 841, IMRB, Department of Genetic, Psychiatry Genetic Team, Créteil, France
8. ⁸CEA Neurospin, NMR Lab, Gif-sur-Yvette, France
9. ⁹AP-HP, Department of Adolescent Medicine, Cochin Hospital, University Paris 5, Paris, France

Correspondence: Dr M Wessa, INSERM, U797, CEA – INSERM Research Unit 'Neuroimaging and Psychiatry', IFR49, University Paris-Sud 11 and University Paris 5, Hospital Department Frédéric Joliot, Orsay, France. E-mail: michele.wessa@zi-mannheim.de

¹⁰These authors contributed equally to this work.

Received 16 November 2006; Revised 29 March 2007; Accepted 3 April 2007; Published online 1 May 2007.

Abstract

Bipolar disorder has been associated with anatomical as well as functional abnormalities in a brain network that mediates normal and impaired emotion regulation. Previous brain imaging studies have highlighted the subgenual cingulate (SC) and the amygdalo-hippocampal (AH) complex as core regions of this network. Thus we investigated white matter (WM) fiber tracts between the SC and the AH region, the uncinate fasciculus, as well as between two control regions (pons and cerebellum), using diffusion tensor imaging tractography in 16 euthymic bipolar patients (BP) and 16 sex-, age- and handedness-matched controls. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the reconstructed fiber bundle and the number of virtual reconstructed fibers were compared between groups. The tractography results revealed a significantly increased number of reconstructed fibers between the left SC and left AH in BP as compared to healthy controls. FA and ADC of the reconstructed fiber tract did not differ significantly between the groups. Furthermore, no significant group differences were observed neither for reconstructed fiber tracts between the right SC and right AH nor between the control regions. The present results suggest an altered WM pathway between the left SC and AH region and thus extend previous findings of anatomical and functional modifications in these structures in BP.