Diffusion tensor tractography in mesencephalic bundles: relation to mental flexibility in detoxified alcohol-dependent subjects.
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.
Chanraud
Sandra
S
INSERM, U797 Research Unit Neuroimaging and Psychiatry, IFR49, Orsay, France.
Reynaud
Michel
M
Wessa
Michèle
M
Penttilä
Jani
J
Kostogianni
Nikoleta
N
Cachia
Arnaud
A
Artiges
Eric
E
Delain
Françoise
F
Perrin
Murielle
M
Aubin
Henri-Jean
HJ
Cointepas
Yann
Y
Martelli
Catherine
C
Martinot
Jean-Luc
JL
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