Ripley T L, Borlikova G, Lyons S, Stephens D N
Sussex Centre for Research in Alcohol, Alcoholism and Drug Dependence, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
Eur J Neurosci. 2004 Jan;19(2):415-25. doi: 10.1111/j.0953-816x.2003.03114.x.
The acquisition of a conditioned response to a cue associated with a fearful event has been shown to be impaired in animals that had been repeatedly withdrawn from ethanol, but not in animals with the same chronic ethanol treatment but only a single withdrawal episode [D. N. Stephens et al. (2001) Eur. J. Neurosci., 14, 2023-2031]. Lesion studies have shown that the amygdala plays a vital role in this type of conditioning process. Here we investigate aspects of conditioning for appetitive reinforcers in operant tasks, also shown to rely on amygdala processing, in rats following repeated withdrawal from ethanol. Rats were chronically treated with either an ethanol-containing liquid diet for 24 days continuously (single withdrawal) or interspersed with 2 x 3-day withdrawal periods (repeated withdrawal), or with a control diet (control). Two weeks after the final withdrawal, operant training began. In tasks that are impaired by lesions of the basolateral amygdala, conditioned reinforcement and reinforcer devaluation, there was no effect of chronic ethanol treatment or withdrawal on acquisition or performance. However, in a task that is dependent upon functioning of the central nucleus of the amygdala, Pavlovian-to-instrumental transfer, the single and repeated withdrawal groups were significantly impaired. Therefore, chronic ethanol treatment and withdrawal resulted in deficits in behavioural tasks that are sensitive to central but not to basolateral amygdala lesions, and may reflect different sensitivities of these areas to ethanol.
在与恐惧事件相关的线索上获得条件反应，已被证明在反复戒断乙醇的动物中受损，但在接受相同慢性乙醇处理但仅经历一次戒断事件的动物中未受损[D. N. 斯蒂芬斯等人（2001年）《欧洲神经科学杂志》，14卷，2023 - 2031页]。损伤研究表明，杏仁核在这种类型的条件作用过程中起着至关重要的作用。在此，我们研究了在操作性任务中，对奖赏性强化物的条件作用的各个方面，该条件作用也被证明依赖于杏仁核的处理，研究对象是反复戒断乙醇后的大鼠。大鼠被长期给予含乙醇的液体饲料，持续24天（单次戒断）或穿插2个3天的戒断期（反复戒断），或给予对照饲料（对照）。最后一次戒断两周后，开始操作性训练。在因基底外侧杏仁核损伤而受损的任务中，即条件强化和强化物贬值任务，慢性乙醇处理或戒断对习得或表现没有影响。然而，在一项依赖于杏仁核中央核功能的任务中，即巴甫洛夫式到工具性转换任务，单次和反复戒断组均显著受损。因此，慢性乙醇处理和戒断导致对杏仁核中央核而非基底外侧杏仁核损伤敏感的行为任务出现缺陷，这可能反映了这些区域对乙醇的不同敏感性。
