Borlikova Gilyana G, Elbers Nicoliene A, Stephens David N
Department of Psychology, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
Eur J Neurosci. 2006 Jul;24(1):205-16. doi: 10.1111/j.1460-9568.2006.04901.x.
Repeated exposure of rats to withdrawal from chronic ethanol reduces hippocampal long-term potentiation and gives rise to epileptiform-like activity in hippocampus. We investigated whether such withdrawal experience also affects learning in tasks thought to be sensitive to hippocampal damage. Rats fed an ethanol-containing diet for 24 days with two intermediate 3-day withdrawal episodes, resulting in intakes of 13-14 g/kg ethanol per day, showed impaired negative patterning discrimination compared with controls and animals that had continuous 24-day ethanol treatment, but did not differ from these animals in the degree of contextual freezing 24 h after training or in spatial learning in the Barnes maze. Repeatedly withdrawn animals also showed increased numbers of responses in the period immediately before reinforcement became available in an operant task employing a fixed-interval schedule although overall temporal organization of responding was unimpaired. Thus, in our model of repeated withdrawal from ethanol, previously observed changes in hippocampal function did not manifest at the behavioural level in the tests employed. The deficit seen after repeated withdrawal in the negative patterning discrimination and over-responding in the fixed-interval paradigm might be related to the changes in the functioning of the cortex after withdrawal.
让大鼠反复经历慢性乙醇戒断会降低海马体的长时程增强效应，并在海马体中引发类癫痫样活动。我们研究了这种戒断经历是否也会影响那些被认为对海马体损伤敏感的任务中的学习。给大鼠喂食含乙醇的饮食24天，期间有两次为期3天的中间戒断期，每天乙醇摄入量为13 - 14克/千克，与对照组和接受持续24天乙醇处理的动物相比，这些大鼠在负性模式辨别任务中表现受损，但在训练后24小时的情境性僵立程度或在巴恩斯迷宫中的空间学习方面与这些动物没有差异。在采用固定间隔时间表的操作性任务中，反复经历戒断的动物在强化即将出现之前的时间段内也表现出反应次数增加，尽管反应的整体时间组织未受损害。因此，在我们的乙醇反复戒断模型中，先前观察到的海马体功能变化在所用测试的行为水平上并未表现出来。反复戒断后在负性模式辨别中出现的缺陷以及在固定间隔范式中的过度反应可能与戒断后皮质功能的变化有关。
