Associative blocking to reward-predicting cues is attenuated in ketamine users but can be modulated by images associated with drug use
Associative blocking to reward-predicting cues is attenuated in ketamine users but can be modulated by images associated with drug use
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DOI：
10.1007/s00213-012-2791-0
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发表时间：
2013-01-01
影响因子：
3.4
通讯作者：
Curran, H. Valerie
中科院分区：
文献类型：
--
作者：
Freeman, Tom P.;Morgan, Celia J. A.;Curran, H. Valerie
阻塞是一种联想学习过程，在精神分裂症中会减弱，可以通过线索显着性进行调节，并伴随着选择性注意的变化。反复接触氯胺酮可以模拟精神分裂症的各个方面，并且频繁使用者会选择性地关注药物的图像。本研究旨在确定 (1) 氯胺酮使用者是否表现出对奖励预测线索的减弱阻断，以及 (2) 药物线索是否可以调节阻断并导致对这些个体的奖励同样具有预测作用的中性线索黯然失色。根据药物线索对氯胺酮使用者 (n = 18) 和多种药物对照 (n = 16) 进行评估奖励预测错误任务，该任务将巴甫洛夫奖励调节后的阻塞和遮蔽索引到中性和药物相关线索。还评估了精神分裂、抑郁、药物史和氯胺酮依赖。与对照组相比，氯胺酮使用者表现出妄想、精神分裂和抑郁症状加重，并且阻塞线索减少，这可以通过对阻塞线索的更高准确度来证明。与对照相比，与毒品相关的线索对阻断具有抵抗力，并且被认为对于氯胺酮使用者赚钱更重要。两组都显示出药物线索掩盖了中性线索，并且氯胺酮使用者对这两种线索的重要性评级高于对照组。这些发现提供了第一个证据，表明（1）谷氨酸能扰动与阻断减少有关，（2）阻断可以通过药物相关线索的存在来调节。药物线索使选择性学习“替代奖励”产生偏差的能力对于基于成瘾治疗的应急管理具有影响。
Blocking is an associative learning process that is attenuated in schizophrenia, can be modulated by cue salience and is accompanied by changes in selective attention. Repeated exposure to ketamine can model aspects of schizophrenia, and frequent users selectively attend to images of the drug.This study aimed to establish whether (1) ketamine users show attenuated blocking to reward-predicting cues and (2) drug cues can modulate blocking and cause overshadowing of neutral cues that are equally predictive of reward in these individuals.Ketamine users (n = 18) and polydrug controls (n = 16) were assessed on the Drug Cue Reward Prediction Error Task, which indexes blocking and overshadowing to neutral and drug-related cues following Pavlovian reward conditioning. Schizotypy, depression, drug history and ketamine dependence were also assessed.Compared to controls, ketamine users showed elevated delusional, schizotypal and depressive symptoms, and a reduction in blocking as evidenced by higher accuracy to blocked cues. Drug-related cues were resistant to blocking and seen as more important for earning money by ketamine users compared to controls. Both groups showed overshadowing of neutral cues by drug cues, and ketamine users gave both of these cues higher importance ratings than controls.These findings provide the first evidence that (1) glutamatergic perturbation is linked to a reduction in blocking and (2) blocking can be modulated by the presence of drug-related cues. The ability of drug cues to bias selective learning about 'alternative rewards' has implications for contingency management based addiction treatments.