The Study Of Facial Expression Information Processing Mechanism Based On Electroencephalogram

Facial expression is a kind of non-verbal communication in daily life,which contains rich emotional information,thereby playing an important role in social communication.In this research event-related potentials(ERPs)was utilized to investigate the mechanism of attentive processing and pre-attentive automatic processing of facial expression information.The research is divided into the following three parts:Firstly,in order to explore the attentive processing of facial expressions,six kinds of facial expressions which selected from one person were used as stimuli and a single picture random presentation paradigm was employed.The participants were required to pay attention to the pictures and discriminate the type of the facial expression.By observing the amplitude and latency of ERPs components induced by different facial expressions,also the whole brain activation,the results indicated that,there were no significant differences between the early ERPs components elicited by different facial expressions.And the main activation area of the brain during the stimulation presentation was located on the posterior area.In addition,the pre-frontal cortex was activated too,which is responsible for emotional regulation.Secondly,the visual mismatch negativity(VMMN)was utilized as an index to investigate the pre-attentive automatic processing of facial expressions.Using the expression related Oddball paradigm,and selecting schematic facial expression pictures as stimuli,participants were required to focus their attention on the change of the cross which in the central of the visual field.During the experiment the subjects were asked to making the corresponding key answer to the change immediately,while ignoring the surrounding schematic facial expression pictures.The VMMN induced by positive and negative expressions were measured and analyzed.The results showed that the information of facial expressions could be processed automatically,and the VMMN elicited by negative facial expressions were significantly larger than the VMMN elicited by positive facial expressions by which exhibited significantdifferences between the mechanism of automatic processing positive and negative expressions.Thirdly,using the experimental method of the second part(set as control group)to study the automatic processing of facial expressions in patients with social anxiety disorder(SAD)including before and after the psychological intervention.Through the analysis of the VMMN and compared with the control group,the results showed that there were no significant differences between the positive VMMN and the negative VMMN;the VMMN elicited by negative expression was significantly lower in SAD participants than those in control group,exhibited the functional dysfunction of automatic processing negative facial information in SAD patients;after 12 weeks of psychological intervention,although the condition of patients with SAD has eased,the effect was not significant.To sum up,we believe that the processing of facial expressions is very fast and automatically.To investigate the automatic processing of facial expressions in health participants and patients with SAD,and analyze the difference between them,can provide a reference for the diagnosis and treatment of SAD,which has important clinical significance.