The Subliminal Emotion Stroop Effect In The Patients With Major Depression: An Event-related Potential Study

Objects:In order to examine the effect of cognitive biases on emotion perception in depression,this study used the emotional task to research the cognitive function of the depression with ERPs,and wanted to research the neurophysiology of the depression further.The aims of the present study were as follows:(1)To explore the influence of emotion stimuli to the cognitive processing.(2) to investigate the deference cognitive processing for the patients with major depression compared to the control group.(3) To provide more evidence to the diagnosis and treatment of MDD.Methods:26 patients with depression and 24 normal controls took part in the study.Doing the emotion Stroop task,they were asked to response to the colorful rectangles(presented for 200ms) as quickly as possible,which were following the Chinese emotion words as priming stimuli presented for 20ms.The behavior and event-related potential data were recorded during the task.Results:(1) The results of behavior data showed there were no significant difference of the correct rate between depression and control group.The reaction time(RT) of depression patients were longer than the control group,especially to the negative and neutral stimuli(p＜0.01).In control group the RT to the positive words were longer than the neutral (p＜0.01),but not in the patients group(p＜0.01).(2) Referring the average ERPs and previous study,the amplitude and latency time of following components were analyzed N1,P1,N2,P3, N4,PSW.N1:the amplitude of MDD were larger than the control group(but no significant,(p＞0.05)).The latency time were significant longer than the control group(p＜0.01 ).P1:In both groups the amplitude of neutral words were larger than the positive words(p＜0.01).And the latency time of the patient were much longer than the control(p＜0.01). N2:In both group the amplitude of the neutral words were larger than the negative and positive words(p＜0.01).P3:the amplitude of the patient were smaller than the control when the negative words were the priming stimuli(p＜0.05).And that of neutral words were larger than the positive words(p＜0.05).N400:the amplitude of the patient were smaller than the control when the negative words were the priming stimuli(p＜0.05). PSW:the amplitude of the patient were smaller than the control when the negative words were the priming stimuli(p＜0.05).Conclusions:(1) There were significant emotion Stroop effect in both group;(2) Patients were significantly influenced by emotion stimuli at the early stage of emotion processing,so the psychological resource were reduce in the late stage of emotion processing.(3) The study supported the parallel model of emotion valence.