Clinical Psychopharmacology Unit, University College London, UK.
National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
Addict Biol. 2020 Jul;25(4):e12802. doi: 10.1111/adb.12802. Epub 2019 Jul 22.
Little is known about the neural functioning that underpins drug valuation and choice in addiction, including nicotine dependence. Following ad libitum smoking, 19 dependent smokers (smoked≥10/day) and 19 occasional smokers (smoked 0.5-5/week) completed a decision-making task. First, participants stated how much they were willing-to-pay for various amounts of cigarettes and shop vouchers. Second, during functional magnetic resonance imaging, participants decided if they wanted to buy these cigarettes and vouchers for a set amount of money. We examined decision-making behaviour and brain activity when faced with cigarette and voucher decisions, purchasing (vs not purchasing) cigarettes and vouchers, and "value signals" where brain activity correlated with cigarette and voucher value. Dependent smokers had a higher willingness-to-pay for cigarettes and greater activity in the bilateral middle temporal gyrus when faced with cigarette decisions than occasional smokers. Across both groups, the decision to buy cigarettes was associated with activity in the left paracingulate gyrus, right nucleus accumbens, and left amygdala. The decision to buy vouchers was associated with activity in the left superior frontal gyrus, but dependent smokers showed weaker activity in the left posterior cingulate gyrus than occasional smokers. Across both groups, cigarette value signals were observed in the left striatum and ventromedial prefrontal cortex. To summarise, nicotine dependence was associated with greater behavioural valuation of cigarettes and brain activity during cigarette decisions. When purchasing cigarettes and vouchers, reward and decision-related brain regions were activated in both groups. For the first time, we identified value signals for cigarettes in the brain.
关于药物价值评估和选择的神经功能基础，包括尼古丁依赖，目前知之甚少。在自由吸烟后，19 名依赖吸烟者（每天吸烟≥10 支）和 19 名偶尔吸烟者（每周吸烟 0.5-5 支）完成了一项决策任务。首先，参与者表示他们愿意为不同数量的香烟和商店代金券支付多少钱。其次，在功能磁共振成像期间，参与者根据设定的金额决定是否购买这些香烟和代金券。我们研究了在面临香烟和代金券决策、购买（或不购买）香烟和代金券以及“价值信号”时的决策行为和大脑活动，当大脑活动与香烟和代金券的价值相关时，就会出现“价值信号”。与偶尔吸烟者相比，依赖吸烟者在面临香烟决策时对香烟的支付意愿更高，双侧颞中回的活动也更高。在两组参与者中，购买香烟的决定与左旁扣带回、右伏隔核和左杏仁核的活动有关。购买代金券的决定与左额上回的活动有关，但与偶尔吸烟者相比，依赖吸烟者的左后扣带回的活动较弱。在两组参与者中，都观察到了与香烟价值相关的信号，出现在左侧纹状体和腹内侧前额叶皮质。总之，尼古丁依赖与对香烟的更大行为估值以及在香烟决策时的大脑活动有关。当购买香烟和代金券时，两组参与者的奖励和决策相关脑区都被激活。这是首次在大脑中识别出与香烟相关的价值信号。
