Differential impairment patterns of the corticospinal tract segments in alcohol dependence

Background: Previous studies have reported inconsistent findings regarding corticospinal tract (CST) changes in alcohol dependence. Here, we aimed to clarify this issue by examining the micro-structural integrity differences of distinct CST segments between alcohol-dependent patients and healthy controls. Methods: Diffusion tensor imaging was performed in a total of 39 male individuals, including 19 alcohol-dependent patients and 20 age-matched healthy controls. CST was reconstructed using tractography and was divided into inferior and superior segments at the level of the lateral sulcus. Multiple diffusion measures of each segment were compared between two groups. Results: For the bilateral whole CSTs, no diffusion measures showed significant between-group differences. However, compared to healthy controls, alcohol-dependent patients exhibited decreased FA and increased RD in the left-superior segment, increased FA and decreased RD/MD in the left-inferior segment, increased AD/MD in the right-superior segment, decreased RD/MD in the right-inferior segment. Conclusions: These findings suggest that CST impairments may vary with the fibre arrangement patterns of its segments in alcohol dependence. Keypoints We reconstructed the CST using tractography based on DTI data and divided the CST into different segments in order to explore more detailed micro-structural integrity changes in alcoholisms. Alcohol-dependent patients showed decreased RD and MD for the bilateral inferior segments of the CSTs. The left-superior segment exhibited decreased FA and increased RD while the right one exhibited increased AD and MD. These findings suggest that CST impairments may vary with the fiber arrangement patterns of its segments in alcohol dependence. In future work, more elaborate segmentation schemes and lager samples should be used to test the reproducibility of our findings.