Abstract: In this study, the monetary reward delay task was used to investigate the expectation and feedback processing and electrophysiological mechanism of heroin abstainers on monetary reward and loss. Twenty-four male heroin abstainers were selected from a compulsory isolation drug rehabilitation institute, they were assessed by professional doctors in drug rehabilitation institute to meet DSM-IV diagnostic criteria for opioid dependence. Twenty-four adult male participants were recruited. After statistical test, there was no significant difference in age and years of education between the two groups. In addition, all participants had normal vision or corrected vision, and had no history of mental illness or other serious diseases. The experimental process was as follows: firstly, the fixation mark of 1000 ms was presented on the computer screen, and then the clues of 400 ms (52 reward clues trials, 52 loss clues trials and 26 neutral clues trials were presented randomly), then the fixation mark of 2000~2500 ms was presented, and then the white square stimulation of 300 ms was presented (When the stimulus appears, the participants need to press the J key quickly and accurately. The responses made by the participants between the appearance and disappearance of the white square stimulus were correct responses, and the responses made before or after the appearance of the white square stimulus were all wrong responses. In order to keep the overall accuracy of the subjects at about 50%, the presentation time of the white square was adjusted with the task performance of participants. The presentation time of the white square in the next trial was reduced by 10 ms when the participants reacts correctly, and the reaction error was increased by 10 ms). Then 1300 ms fixation mark was presented, and finally 2000 ms feedback was presented. The results showed that there was no significant difference in P3 amplitude induced by different cues between the two groups in the expected stage. During the feedback stage of money reward, the RewP amplitude induced by money gain condition in heroin abstainers group was significantly smaller than that in control group, but there was no significant difference between the two groups under the condition of no gain and no loss. In addition, there was no significant difference between the P3 amplitude induced by money gain condition and the P3 amplitude induced by no gain and no loss condition in heroin abstainers group, while the P3 amplitude induced by money gain condition was significantly larger than that induced by no gain and no loss condition in control group. In the feedback stage of money loss processing, there was no significant difference in RewP amplitude between the two groups, and P3 amplitude induced by money loss condition was significantly larger than P3 amplitude induced by no income and no loss condition. The above results indicated that the heroin abstainers' feedback processing of money reward was abnormal, which was manifested in the decrease of their sensitivity to money reward or the decrease of their motivation to approach money reward.

Key words: heroin abstainers, reward, loss, feedback

摘要： 本研究采用金钱奖赏延迟任务考察了海洛因戒断者对金钱奖赏和损失的预期和反馈加工及其电生理机制。结果发现，预期阶段两组被试由不同线索诱发的P3波幅不存在显著性差异。在金钱奖赏加工的反馈阶段，海洛因戒断组由金钱收益条件诱发的RewP波幅显著小于对照组由金钱收益条件诱发的RewP波幅，而在无收益无损失条件下两组被试诱发的RewP波幅不存在显著性差异。此外，海洛因戒断组由金钱收益条件诱发的P3波幅与无收益无损失条件诱发的P3波幅不存在显著性差异，而对照组由金钱收益条件诱发的P3波幅显著大于其由无收益无损失条件诱发的P3波幅。在金钱损失加工的反馈阶段，由金钱损失和无收益无损失条件诱发的RewP波幅在两组被试之间不存在显著性差异，且两组被试由金钱损失条件诱发的P3波幅均显著大于其由无收益无损失条件诱发的P3波幅。以上结果说明海洛因戒断者的金钱奖赏反馈加工存在异常，具体表现为其对金钱奖赏的敏感性降低或对金钱奖赏的趋近动机减弱。

关键词: 海洛因戒断者, 奖赏, 损失, 反馈