To Explore The Role Of Impulsive Decision-making Disorder In Heroin Addiction Based On The Technique Of FMRI And ERP

Objective To explore the reaction pattern of impulsive behavior of heroin addicts,brain regions associated with impulsive behavior and the characteristic of event-relatedpotentials evoked by negative outcomes, and to interpret the nervous mechanisminvolving in addiction and relapse in heroin abusers from point of view ofdecision-making behavior.Method (1) Utilization of the paradigms for psychological experiment, the Iowagambling task (IGT) were performed both in heroin addiction group (HA group) andhealth control group (HC group), the reaction pattern of impulsive behavior of both twogroup were compared;(2) the IGT were performed both in HA group HC group and thefunctional magnetic resonance imaging(fMRI) scan were underwent simultaneously. Allthe above data were gathered and then were analysed by Stastistical ParametticMapping5(SPM5) software to explore both the brain regions and their functionalchanges related to impulsive decision-making;(3) the IGT were performed both in HAgroup HC group and the inspection of electroencephalography were underwent in all thesubjects concurrently. Following the collection of data, the amplitude and latency of theevent-related potentials(ERPs) evoked by negative outcomes were compared betweenthe two groups, and then the relationship between the amplitude and latency of ERPsand the scores of Barratt Impulsiveness Scale(BIS-11) were analyzed separately.Results (1) The decision-making course affected the net score remarkably in HC group, whereas contrary result was observed in HA group (P<0.05); there was nostatistical difference between the numbers of low-frequency punishment cards andhigh-frequency punishment cards which subjects selected in HA group, while statisticaldifference was absent in HC group (P<0.05). Furthermore, the difference between thenumber of low-frequency punishment cards and high-frequency punishment cards inHC group was higher than that of HA group (P<0.05).(2) Based on the reults of fMRIanalysing, the right orbitofrontal cortex (OFC), dorsolateral prefrontal cortex (DLPFC),left ventromedial prefrontal cortex (MPFC) and anterior cingulate cortex (ACC) wereactivitied in both two groups, but the right OFC were more active, while the rightDLPFC and left MPFC were weaker in HA group compared wiht HC group. Meanwhile,activation of right lenticular nucleus, right thalamus, right insula, hippocampus and leftcaudate nucleus were observed in HA group (P values less than0.05were considered tobe statistically significant).(3) Both the two groups had visible waveforms of ERN,FRN and P300in electrode of Fz, Cz, Pz and Oz. The amplitude of ERN were markedlylower in HA group [HA:(4.23±0.87) μV, HC(6.11±1.09) μV; t=5.96, P<0.05], but nostatistical difference was found in latency of these two groups [HC:(102.14±28.21)ms,HA:(107.80±24.15)ms; t=-0.62, P=0.54]; the amplitude of FRN were markedly higherin HA group[HA:(10.62±1.91) μV, HC(8.13±2.17) μV; t=5.37, P<0.05], but nostatistical difference was found in latency of these two groups [HC:(282.64±36.53)ms,HA:(268.45±40.91)ms; t=1.51, P=0.14]; the amplitude and latency of P300weremarkedly lower [HA:(4.92±1.14) μV,(293.43±36.21) ms; HC:(7.65±1.59) μV,(332.68±40.15) ms; P<0.05]. Pearson correlation analysis showed, the amplitude ofERN of both two groups were negatively associated with BIS score respectively in bothtwo groups (HC: r=-0.66, HA: r=-0.78; P<0.05), the amplitude of FRN were positivelyassociated with BIS score in both two groups (r=0.77,0.61; P<0.05), and the amplitudeand latency of P300were negatively associated with BIS score in HA group (r=-0.76,-0.52, P<0.05), but the latency of ERN and FRN were not associated with BIS score in both two groups, and the same as the amplitude and latency of P300in HC group.Conclusion Heroin addicts remain deficit in reaction pattern of impulsivedecision-making behavior; brain regions such as prefrontal cortex participate in thedecision-making performing and controlment of impulsiveness are functional abnormal;the abnormal waveforms of ERN, FRN and P300evoked by negative outcomes areassociated with impulsive behavior, indicate that the bad capability of error processing,outcome evaluation and attention; of above-mentioned may be a cause of generation,maintenance and relapse of heroin addiction.