The Effect Of High-definition Transcranial Direct Current Stimulation On Emotional Face Processing In College Students With High Autistic Traits

Objective: Individuals with autistic traits are subclinical groups with many autistic characteristics similar to those of clinical Autism spectrum disorders(ASD)patients.Studies have shown that face processing impairment is common in ASD patients.Face processing is an important component of social cognition,but there are few studies on the face processing of individuals with autistic traits.In this study,eye movement tracking technology was used to explore the difference in face processing between the high and low groups of college students with autistic traits.Secondly,college students with high autistic traits were regarded as the research object,using different polarity high-definition transcranial direct current stimulation(HD-t DCS)to investigate its regulatory effect on the face processing of them,and then to analyze the mechanism of right temporoparietal junction(r TPJ)in face processing and the role of HD-t DCS in regulating social cognitive ability.Methods Study 1: Thirty-three college students with high autistic traits and thirty-one students with low autistic traits were screened out,and their features in face processing were compared with free-viewing task;Study 2: Forty-five college students with high autistic characteristics were randomly divided into three groups and given three different kinds of conditional stimulation:(anodal,cathodal,and sham).All subjects completed the free-viewing task before stimulation,and then received the stimulation intervention of 20 minutes one session per day for five consecutive days.After the stimulation,the eye movement task was completed again,and the effect of HD-t DCS on the index of the three groups under different stimulation conditions was compared.Results Study 1: There were significant differences in the face processing between the high and low groups of autistic students.In the eye region,the fixation time of the high group of autistic students was significantly less than that of the low group(P = 0.024),and the first fixation time(P = 0.067)and the number of fixation count(P = 0.079)was less than that of the low group and close to the significant difference.In the mouth area,the fixation time of high group significantly less than the low group in happy(P =0.002),fear(P = 0.048)and neutral faces(P = 0.044),and the first fixation time(P =0.012)and the number of fixation count(P = 0.007)also significantly less than the low group.Study 2.Before the stimulation,there was no significant difference in eye movement data of the three groups in the eyes and mouth area(P > 0.05).After stimulation,anodal stimulation significantly improved the fixation time of mouth area in high autistic traits students both happy(P = 0.018)and fearful faces(P = 0.001),and fixation count in happy(P = 0.023)and fear(P = 0.001).However,this effect was not found in the eye area(P > 0.05),and cathodal stimulation did not show obvious effect(P > 0.05).Conclusion(1)College students with high autistic traits have abnormal face processing,which is manifested in insufficient attention to the core area of the face(both eyes and mouth areas of interest);(2)Right TPJ plays an important role in face emotion processing,and HD-t DCS anodal stimulation can promote gaze to emotional faces in college students with high autistic traits.