The Study Of Attentional Bias And Nonlinear Characteristics Of EEG In The Heroin Addicts

Heroin addiction caused serious influence to the family and society. In our county, the actual number of addicts has exceeded more than 1.4 million. Heroin addicts are widespread brain damage, including the attention, memory, decision-making and so on. The relapse is the hardest problems to overcome in drug dependence, and the attentional bias of addicts to addiction-related cues is a key factor in the relapse.This study uses heroin-related dot-probe paradigm, and combined with event-related potential(ERP) to study the attentional bias in heroin addicts. ERP which is hidden in the EEG signal is a kind of special potential, it is induced by a specific event and has the very high temporal resolution. In this paradigm, a set of pictures which was evaluated by the addicts served as the cue stimulus, and the orientation of two dots served as the target stimulus when the pictures disappeared in the dot-probe paradigm. In addition, this thesis analyzed the resting state of EEG data which was collected by a simple visual task. The nonlinear characteristics including LZ complexity(LZC) and power spectrum entropy(PSE) of the α rhythm and the whole band of EEG(1 ~ 48Hz) were compared between heroin addicts and normal controls. Through the study, we mainly found some results:(1)According to the behavioral data, heroin addicts have a certain attention bias to heroinrelated cues, and they have a faster response to the dot when the relative position of dot and heroin-related pictures is consistent than it is inconsistent. Meanwhile, it is opposite to controls.(2)When time is locked to the picture, the cues induce larger average amplitude of N1 in the heroin addicts compared with the controls on the occipital region, and the lager average amplitudes of P1 and P2 are induced by the cues in the heroin addicts compared with the controls on the central region. The result illustrates that the addicts have intensive processing to the cues.(3)When the time is locked to the dot, the period of P3 in the addicts is shorter than the controls. That is to say, the addicts have a faster processing to the target than the controls and the cues influence the processing to the latter target.(4)The result of the nonlinear characteristics of the EEG-α rhythm and the whole band of EEG show that addicts have larger LZC and PSE compared with the controls. However, the results show that there are obvious more electrodes which have significant difference on the EEG-α rhythm than on the whole band of EEG, which reflects the important position of the EEG-α rhythm in the resting state of EEG. LZC and PSE is suited to studying the resting state of EEG in addicts.