| Objective: Panic disorder (PD) is one of the most common and importantanxiety disorders in the general hospital. PD is characterized by recurrent, suddenonset, unpredictable and intense horror experience. The mechanism of PD has not yet been fully clarified, and there was a lack of objective biological indicator.The fearful experience of panic attacks is the main clinical manifestations of patients with panic disorder. However, the main theoretical hypotheses on the PD focus on cognitive bias and cognitive disaster, and few studies focus on the brainmechanisms of emotion processing. Whether there is abnormal brain activationwhen patients with panic disorder face the emotional information? It is still unknown and worthy of further exploration.The studies on human brain function consist of the spatial orientation of neurons and the time course of information processing. FMRI studies found, therewere abnormal activation of the anterior cingulate cortex and amygdala in the patients with panic disorder. But there is no report on the brain mechanisms of information processing when patients with panic disorder face the negative emotional information. The event-related potential (ERP) technique in cognitive neuroscience allows scientists to observe human brain electrical activation and use it to investigate the time course of emotional processing. It can accurate record a seriesof dynamic processing within a millisecond, such as the emotion recognition, attention and appraision. The LPP is frequently assumed to reflect an early electrocortical of attentional and cognitive bias to the emotional stimuli. The earlier components, such as P2, N2reflect the early emotional processing in recognition andattention, and the dynamic processing of emotional information. The aim of thepresent study is to investigate the time course characteristics of emotional proces sing in patients with panic disorder using ERP technique.Method:17PD patients (12females, all right-handed) and17age and gender matched healthy volunteers (11females, all right-handed) with an age rangeof18–60participated in the current study. All subjects were interviewed by SCID and were required to complete the HAMA. The patients also completed the PDSS. Stimulus sequence consisted of50pictures which were selected from the International Affective Picture System (IAPS); of these,25depicted neutral scenesand25depicted unpleasant scenes. After the offset of each picture, participantsrated the picture on the dimensions of valence and arousal. After off-line analysis, the different deviant mean amplitudes of LPP were measured at fronto-parietalregions of15electrodes (F3, Fz, F4, Fc3, Fcz, Fc4, C3, Cz, C4, CP3, Cpz, Cp4, P3, Pz, P4). And peak values of P2and N2in fronto-parietal electrodes werealso measured considering the abnormality of early stage emotional processing of PD group. Within-group and between-group comparisons were performed usingRMANOVE. Pearson correlations were performed between the magnitudes of theLPP for each deviant and HAMA, PDSS scores.Results:1.There was a significant group difference in arousal ratings (F1,32=12.064,P=0.001). The arousal ratings of negative pictures were significantly decreased inPD group compared to the control group.2.PD group showed significant condition effect on P2component (F1,32=11.084, P=0.002). Negative condition elicited higher P2than neutral condition. In control group, there is no statistical difference on P2component between conditions (F1,32=2.216, P=0.146).3. The N2peak amplitudes elicited by negative pictures (F1,32=4.404, P=0.044) and neutral pictures (F1,32=2.964, P=0.048) were all significantly decreased inPD group compared to the control group.4.The LPP mean amplitudes elicited by negative pictures (F1,32=4.147, P=0.048) and neutral pictures (F1,32=4.928, P=0.046) were all significantly decreasedin PD group compared to the control group. RMANOVA yielded group main effect and electrode main effect on the LPP, but only a group effect on the parietal LPP (Cz: F1,32=5.069, P=0.031; Cpz: F1,32=7.272, P=0.011; Pz: F1,32=3.820, P=0.041).5.Within-group and between-group comparisons did not showed any observa ble difference in latency of P2and N2components.6.Emotional LPP amplitude and HAMA, PDSS score had no correlation (Ps>0.05).Conclusion:1.There was an impairment of attentional and appraisal processing of emotional among PD patients: the negative information enhanced the recognition and avoid processing, weakened the appraisal processing; the neutral information weakened the attentional and appraisal processing. It was significant at the parietal-central regions.2.There was no speed abnormality of early emotional processing in PD group in present paradigm.3.The characteristics of emotional processing and the severity of PD patients had no correlation, and the LPP may be a disease-related index of panic disorder, rather than state index... |
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