title: Diffusion tensor tractography in mesencephalic bundles: relation to mental flexibility in detoxified alcohol-dependent subjects.
abstract: Components of the corticocerebellar circuit and the midbrain individually play a central role in addictive processes and have been associated with altered volumes and impairment of cognitive flexibility in alcohol-dependent subjects. The microstructure of white matter bundles composing the corticocerebellar network and passing through the midbrain was studied using diffusion tensor imaging in a group of detoxified alcohol-dependent men (n=20) and a group of healthy men (n=24). The relationship between properties of these white matter bundles and cognitive flexibility performance was investigated in alcohol-dependent subjects. Bundles connecting two regions of interest were analyzed using a fiber-tracking quantitative approach, which provided estimates of the fractional anisotropy and the apparent diffusion coefficient, as well as the number of tracked fibers normalized by the volume of regions of interest. Within the bundles running between the midbrain and pons, a mean of 18% fewer fibers per unit volume were tracked in alcohol-dependent men than in healthy controls. In addition, the normalized number of these fibers correlated with the performance in the Trail-Making Test part-B. Even though the alcohol-dependent subjects were detoxified and apparently neurologically intact, their earlier excessive use of alcohol seems to be associated with altered neural microstructure of mesencephalic white matter bundles, which may contribute to their cognitive flexibility impairment.
authors.affiliation: INSERM, U797 Research Unit Neuroimaging and Psychiatry, IFR49, Orsay, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Chanraud
authors.forename: Michel
authors.initials: M
authors.lastname: Reynaud
authors.forename: Michèle
authors.initials: M
authors.lastname: Wessa
authors.forename: Jani
authors.initials: J
authors.lastname: Penttilä
authors.forename: Nikoleta
authors.initials: N
authors.lastname: Kostogianni
authors.forename: Arnaud
authors.initials: A
authors.lastname: Cachia
authors.forename: Eric
authors.initials: E
authors.lastname: Artiges
authors.forename: Françoise
authors.initials: F
authors.lastname: Delain
authors.forename: Murielle
authors.initials: M
authors.lastname: Perrin
authors.forename: Henri-Jean
authors.initials: HJ
authors.lastname: Aubin
authors.forename: Yann
authors.initials: Y
authors.lastname: Cointepas
authors.forename: Catherine
authors.initials: C
authors.lastname: Martelli
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Martinot
mesh_terms: D000328:Adult; D000368:Aged; D019973:Alcohol-Related Disorders / Q000473:pathology* / Q000523:psychology*; D002531:Cerebellum / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D003071:Cognition / Q000187:drug effects; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008636:Mesencephalon / Q000473:pathology*; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology; D009483:Neuropsychological Tests