A Contrastive Study Of Reverse Learning Between Withdrawal Heroin Addicts And Normal Persons

Substance addiction has always been a worldwide issue,more and more researchers believed that the substance addicts may be related to one's impaired capacity of reversal learning in recent years.Reversal learning requires an individual to respond adaptively to the changing environment.However,the studies showed the general impairment of reversal learning among substance addicts.The impairment,at the behavioral level,showed substance addicts need more trials to reverse the stimulus-outcome association when compared to controls,at the neural level,substance addicts showed abnormal brain activities in regions when compared to controls,such as the ventral prefrontal cortex,the dorsal prefrontal cortex and other brain regions.In addition,substance-related cues are the high risk factors for triggering addict's craving and approach to addictive substance.Studies have showed that the substance addicts have a cuing response on substance-related cues compared to neutral cues,which could affect their cognitive processing and inducing situational reversal learning impairment(e.g.the reverse learning impairment of addicts under substance-related cues is more obvious than neutral cues)which specific to substance-related situations.However,most of the previous studies have investigated the reversal learning of addicts such as cocaine and alcohol,and the ability of reverse learning of opiate addicts is not clear.Therefore,in order to further investigate the performance of opiate addicts' reversal learning and the effect of drug-related cues on their performance,we selected male heroin addicts(heroin is the most widely abused opioid)from the Forced Detoxifcation Center,Gansu,China,conducting two experiments to solve the shortcomings of previous research.In Experiment 1,the probabilistic reversal learning task was used to investigate the general reversal learning of heroin addicts;in the second experiment,we used a cued probabilistic reversal learning task combined with neutral and drug-related cues to investigate whether the drug-related cues have an impact on heroin addicts' reversal learning.The results showed that(1)Compared with controls,the reversal learning of heroin addicts significantly needed more trials to reverse stimulus-outcome associations.(2)Compared with controls,heroin addicts significantly needed more trials to reverse stimulus-outcome associations under drug-related cues than neutral-related cues.The results of our study suggested that heroin addicts cannot change the stimulus-outcome associations flexibly connected to the adaptive response,especially the difficulties in reversing the learned stimulus-outcome associations under drug-related cues,which may be an important risk factor causing relapse in heroin addicts.In future work,we need to explore the neural mechanism of the effect of substance-related cues on the reversal learning of addicts.