Nicotine addiction is characterized as a neural circuit dysfunction, particularly with regard to the alterations in central reward pathways. The insula, a cortical region that is thought to play a central role in this reward circuitry, has been implicated in the maintenance of nicotine addiction. However, it remains largely unclear about the white matter (WM) microstructural alterations of insula in nicotine addiction and whether the WM alterations of insula could predict smoking cessation outcomes. In this study, 58 male nicotine-dependent smokers and 34 matched male nonsmoking controls were recruited. After a 12-week smoking cessation treatment with varenicline, 38 smokers relapsed, and 20 did not relapse. Diffusion tensor imaging and probabilistic tractography were used to investigate the differences of WM tracts of insula between smokers and nonsmokers. Relative to nonsmokers, in the left hemisphere, smokers showed lower fractional anisotropy (FA) in the fiber tracts of anterior insula cortex-to-nucleus accumbens and posterior insula cortex-to-nucleus accumbens; in the right hemisphere, smokers showed higher FA, and lower axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) in the fiber tracts of anterior insula cortex-to-medial orbitofrontal cortex, posterior insula cortex-to-medial orbitofrontal cortex, and posterior insula cortex-to-nucleus accumbens. However, there were no differences of WM diffusion properties between relapsers and nonrelapsers. This study is the first using probabilistic tractography to exclusively clarify the precise roles of insular WM tracts in smokers, which may provide new insights into the underlying neurobiology of nicotine addiction.

尼古丁成瘾的特点是神经回路功能障碍，特别是在中枢奖励途径的改变方面。脑岛是一个被认为在这种奖励回路中发挥核心作用的皮质区域，它与维持尼古丁成瘾有关。然而，在尼古丁成瘾中脑岛的白质 (WM) 微观结构改变以及脑岛的 WM 改变是否可以预测戒烟结果仍不清楚。在这项研究中，招募了 58 名男性尼古丁依赖吸烟者和 34 名匹配的男性不吸烟对照。用伐尼克兰戒烟治疗 12 周后，38 名吸烟者复发，20 名未复发。扩散张量成像和概率纤维束成像用于研究吸烟者和非吸烟者之间脑岛 WM 束的差异。相对于不吸烟者，在左半球，吸烟者在前脑岛皮层到伏隔核和后脑岛皮层到伏隔核的纤维束中表现出较低的各向异性分数（FA）；在右半球，吸烟者在前岛叶皮质到内侧眶额皮质、后岛叶皮质到内侧眶额皮质的纤维束中显示出较高的 FA，以及较低的轴向扩散率 (AD)、径向扩散率 (RD) 和平均扩散率 (MD)。 -内侧眶额皮质和后脑岛皮质到伏隔核。然而，复发者和非复发者之间的 WM 扩散特性没有差异。