Electrocortical Processing Of Heroin And Emotional Cues In Abstinent Heroin Users

The abnormal cognitive processing of drug cues is a core characteristic of drug dependence. Previous research has suggested that the late positive potential(LPP) of heroin users is increased by heroin-related stimuli because of the attention-grabbing nature of such stimuli for persons with heroin dependence. The present research used the emotional Stroop(eStroop) task to examine whether there was an early posterior negativity(EPN) modulation to heroin cues compared with emotional or neutral stimuli in heroin dependent subjects. Fifteen former heroin users and 15 matched controls performed the eStroop task, which was composed of pictures of positive and negative emotions, heroin-related and neutral pictures with superimposed color squares. Participants responded to the color of the square and not to the picture while behavioral data and event-related potentials were recorded. There were no significant differences of the EPN amplitudes to emotional and neutral stimuli between the heroin users and controls. However, heroin users displayed increased EPN modulation for heroin cues, and this modulation was not present in the controls. Our findings provide the first electrophysiological evidence of an early attentional bias to drug-related pictures in heroin users. The reward mechanism for drug-related cues in heroin addicts is presumed to last a long time due to the addiction memory.