Unconscious Affective Semantic Processing among Patients with Generalized Anxiety Disorder: an Event-related Potential Study
|School||Dalian Medical University|
|Keywords||Generalized anxiety disorder Event-related potentials Emotional semantic Unconscious processing Subliminal stimulation paradigm|
Objective: Generalized anxiety disorder (GAD), also known as chronic anxiety, ischaracterized by excessive uncontrollable worry on the day-to-day events or activities.The pathogenesis of generalized anxiety disorder has not yet been achieved theconsistency of conclusions. According to the information processing model ofgeneralized anxiety disorder and the experimental evidences at present，abnormalunconscious processing of emotional information may be one of the important causes ofGAD.Unconscious processing is characterized by information processing with no or littleawareness, without taking up the attentional resources and without awareness to initiate.Currently, the subliminal stimulation paradigm is widely used to investigate theunconscious processing. Because worry of GAD is a verbal linguistic, thought-basedactivity, this experiment adopt subliminal affective semantic stimulation paradigm.Event-related potentials (ERP) can be accurate to the millisecond and can reflect thedynamic process of cognitive processing, so it is the best technical means of studyingunconscious processing. This study is to explore the unconscious processing of affectivewords in GAD patients by using of ERP and to further analyze whether the differentemotional contents are specific to different distribution of brain region.Methods:12diagnosed patients with GAD and12age, sex and educational levelmatched healthy volunteers were selected for the study. All subjects were interviewedby Structured Clinical Interview for DSM-IV-TR Axis I Disorders-Patient Edition(SCID) and were required to complete the HAMA and HAMD-17.In this study,subliminal affective semantic priming task and a64channel Neuroscanelectroencephalogram were used to record the event-related potentials. After off-lineanalysis, the P1and P3elicited by different emotional words were measured in the frontal, parietal, occipital and the central electrodes. Mean amplitudes and peak latencywere subjected to repeated measures analysis (Repeated measure ANOVA).Results:1. There was no significant effect on RT (F(1,22)=0.374,p＞0.05) across twogroups. The ratings for different emotional words did not show significant effectbetween and within group（F(1,22)=1.419, p＞0.05）.2. As for the mean amplitude of P1and P3, significant effects of hemisphere（p＜0.05） and brain region（p＜0.05） was found, the left hemisphere’s mean amplitudewas higher than the right and frontal was higher than occipital. The main effects ofgroup and the type of emotional words were not observable（p＞0.05）.3. Although no main effects of group and emotional type for the peak latency of P1and P3were found（p＞0.05）, a effect of hemisphere and brain region was obvious（p＜0.05）, the left hemisphere’s latency of P1and P3was longer than the right and thelatency in frontal areas was longer than in occipital. The effect of interaction betweengroup、emotional type and hemisphere was significant（p＜0.05）. Further analysisshowed that in left hemisphere of the normal group, the negative words’ latency waslonger than positive, but not in GAD group.Conclusion:1.In GAD group，there was no significant abnormality in the affective semanticunconscious processing.2. Unconscious processing of emotional semantic information is left-lateralized inboth groups, the left frontal lobule is the main region for emotional semantic processing.