Blaine Sara, Fogelman Nia, Lacadie Cheryl, Constable Todd, Sinha Rajita
Department of Psychological Sciences, Auburn University, Auburn, Alabama, USA.
Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut, USA.
Alcohol Clin Exp Res (Hoboken). 2023 Jun;47(6):1067-1078. doi: 10.1111/acer.15082. Epub 2023 Apr 26.
Alcohol stimulates cerebral blood flow (CBF) in brain reward regions. However, neural processes that support sustained alcohol motivation after the first drink are not well understood.
Using a novel placebo-controlled, randomized, crossover experiment, 27 individuals who binge drink (BD; 15 M, 12 F) and 25 social drinkers (SD; 15 M, 10 F) underwent a behavioral test of self-motivated alcohol consumption using an Alcohol Taste Test (ATT) involving alcoholic and nonalcoholic beer on separate days. The test was followed immediately by perfusion functional magnetic resonance imaging (fMRI). On both days, participants then engaged in a post-scan ATT with placebo beer to assess sustained alcohol self-motivation without active alcohol effects. Linear mixed effects models were used to examine the effects of drinking group on the placebo-controlled effect of initial alcohol motivation on brain perfusion (whole brain corrected p < 0.001, cluster corrected p < 0.025) and on the relationship between placebo-controlled brain perfusion and sustained alcohol motivation.
Initial alcohol self-motivation in the alcohol relative to placebo session led to markedly decreased activation in the medial orbitofrontal cortex (OFC) and the ventral striatum in BD relative to SD, indicative of neural reward tolerance. The BD group also showed an enhanced neural response in behavioral intention regions of the supplementary motor area (SMA) and inferior frontal gyrus (IFG) regions. Moreover, there was greater sustained alcohol motivation in BD than SD in the post-scan ATT in the alcohol relative to placebo session. Correspondingly, only in BD and only in the alcohol session, lower alcohol-induced OFC response correlated with concurrent sensitized SMA response, and each predicted the subsequent sustained higher alcohol motivation in the post-scan ATT.
Alcohol-related OFC tolerance may play an important role in sustained alcohol motivation. Furthermore, both specific alcohol-related neural reward tolerance and premotor sensitization responses may contribute to escalating alcohol motivation to drive excessive alcohol intake, even in individuals without alcohol use disorder.
酒精会刺激大脑奖赏区域的脑血流量（CBF）。然而，首次饮酒后支持持续饮酒动机的神经过程尚不清楚。
采用一项新型的安慰剂对照、随机、交叉实验，27名暴饮者（BD；15名男性，12名女性）和25名社交饮酒者（SD；15名男性，10名女性）使用酒精味觉测试（ATT）进行了一项自我驱动饮酒行为测试，测试中分别在不同日期饮用酒精啤酒和非酒精啤酒。测试后立即进行灌注功能磁共振成像（fMRI）。在这两天，参与者接着饮用安慰剂啤酒进行扫描后ATT，以评估无酒精活性作用下的持续饮酒自我动机。使用线性混合效应模型来检验饮酒组对初始饮酒动机对脑灌注的安慰剂对照效应（全脑校正p<0.001，聚类校正p<0.025）以及安慰剂对照脑灌注与持续饮酒动机之间关系的影响。
与安慰剂组相比，饮酒组中酒精相关的初始饮酒自我动机导致BD组相对于SD组的内侧眶额皮质（OFC）和腹侧纹状体激活明显降低，这表明神经奖赏耐受性。BD组在辅助运动区（SMA）和额下回（IFG）区域的行为意图区域也表现出增强的神经反应。此外，与安慰剂组相比，在酒精组的扫描后ATT中，BD组的持续饮酒动机高于SD组。相应地，仅在BD组且仅在酒精组中，较低的酒精诱导OFC反应与同时出现的SMA反应致敏相关，并且两者都预测了扫描后ATT中随后持续更高的饮酒动机。
与酒精相关的OFC耐受性可能在持续饮酒动机中起重要作用。此外，特定的与酒精相关的神经奖赏耐受性和运动前致敏反应都可能导致饮酒动机升级，从而驱使过量饮酒，即使在没有酒精使用障碍的个体中也是如此。
