中文摘要：

目的：本研究采用金钱奖赏范式探讨不同戒断时长（短期戒断组：平均2．7个月，中期戒断组：平均19．36个月，长期戒断组：平均49．6个月）的毒品戒断者与正常匹配组，在分辨不同额度的金钱奖赏时认知加工能力的损伤和恢复情况。方法：研究中要求被试在三种不同的奖赏条件（45分，1分，0分）下完成Go／No—go任务。结果：脑电结果表明，对不同额度的金钱奖赏加工时，短期戒断组和中期戒断组的脑区功能受损，表现为其诱发的N2和P3波幅在三种条件下差异都不显著；长期戒断组在奖赏条件下诱发的N2和P3平均波幅显著大于0分条件，但是波幅差异的程度显著低于控制组。结论：长期戒断组和控制组在神经激活模式上存在的差异，表明经过三年以上的戒断后，戒毒人员的脑功能显示出一定水平的恢复，但是仍未恢复至正常水平。

英文摘要：

Objective： The current study aimed to explore cognitive function in drug abstainers at different healing phas- es（short-term abstinence group： average of 2.7 months, medium-term abstinence group： 19.36 per month on average, long- term abstinence group： average of 49.6 months） with a monetary reward task. Methods： This study adopted a monetary re- ward paradigm. Participants were required to complete the Go/No-go tasks in three different reward gradients（score of 45, 1, 0）. Results： Eleetroencephalographic（EEG） results showed that the sensitivity to monetary reward was declined in both short- and medium-term abstinence groups who have no different brain activation on the reaction to three different reward gradients. The brain function of long-term abstinence group showed a certain level of recovery, reflected by smaller difference of P3 and N2 amplitudes to monetary reward gradient compared to the control group. Conclusion： The damage of rewards perception, assessment, and expectation caused by drug addiction earl be normalized following a long term post-drug withdrawl.