David Sean P, Munafò Marcus R, Johansen-Berg Heidi, Mackillop James, Sweet Lawrence H, Cohen Ronald A, Niaura Raymond, Rogers Robert D, Matthews Paul M, Walton Robert T
Department of Clinical Pharmacology, University of Oxford, Radcliffe Infirmary, Oxford, UK.
Brain Imaging Behav. 2007 Dec;1(3-4):43-57. doi: 10.1007/s11682-007-9004-1.
To achieve greater understanding of the brain mechanisms underlying nicotine craving in female smokers, we examined the influence of nicotine non-abstinence vs. acute nicotine abstinence on cue-elicited activation of the ventral striatum. Eight female smokers underwent an event-related functional magnetic resonance imaging (fMRI) paradigm presenting randomized sequences of smoking-related and non-smoking related pictures. Participants were asked to indicate by a key press the gender of individuals in smoking-related and non-smoking related pictures (gender discrimination task), to maintain and evaluate attention to the pictures. There was a significant effect of smoking condition on reaction times (RT) for a gender discrimination task intended to assess and maintain attention to the photographs-suggesting a deprivation effect of acute nicotine abstinence and a statistical trend indicating greater RTs for smoking cues than neutral cues. BOLD contrast (smoking vs. non-smoking cues) was greater in the non-abstinent vs. acutely abstinent conditions in the ventral striatum including the nucleus accumbens (VS/NAc). Moreover, a significant positive correlation was observed between baseline cigarette craving prior to scanning and VS/NAc activation (r=0.84, p=0.009), but only in the non-abstinent condition. These results may either be explained by ceiling effects of nicotine withdrawal in the abstinent condition or, may indicate reduced relative activation (smoking vs. neutral contrast) in the VS/NAc in the abstinent vs. non-abstinent conditions in this group of female smokers.
为了更深入了解女性吸烟者对尼古丁渴望的大脑机制,我们研究了尼古丁非戒断状态与急性尼古丁戒断对线索诱发的腹侧纹状体激活的影响。八名女性吸烟者接受了一项与事件相关的功能磁共振成像(fMRI)范式,该范式呈现了吸烟相关和非吸烟相关图片的随机序列。参与者被要求通过按键指出吸烟相关和非吸烟相关图片中人物的性别(性别辨别任务),以保持并评估对图片的注意力。对于旨在评估和保持对照片注意力的性别辨别任务,吸烟状态对反应时间(RT)有显著影响——这表明急性尼古丁戒断存在剥夺效应,并且有统计趋势表明吸烟线索的反应时间比中性线索更长。在包括伏隔核(VS/NAc)的腹侧纹状体中,非戒断状态与急性戒断状态相比,血氧水平依赖(BOLD)对比度(吸烟线索与非吸烟线索)更高。此外,在扫描前的基线香烟渴望与VS/NAc激活之间观察到显著的正相关(r = 0.84,p = 0.009),但仅在非戒断状态下。这些结果可能要么由戒断状态下尼古丁戒断的天花板效应来解释,要么可能表明在这组女性吸烟者中,戒断状态与非戒断状态相比,VS/NAc中的相对激活(吸烟线索与中性线索对比度)降低。