| Objective:Personality refers to a specific combination of emotion,attitude and behavior.This study attempts to explore the neurobiological mechanism of personality traits from vertex-wise and regional-wise two different scales using surface-based morphology analysis(SBM)in healthy adult,in order to study the relationship between brain region's geometry features and personality traits.To further verify the recent study findings that individual regional differences are associated with those of cortical morphology,we related the local functional homogeneity by abstracting the significant areas in area-based analysis,finally finds out the relationship between brain structure and function and provides neural biological basis for the theory of personality traits and personality measurement.Methods:Collecting subjects by putting up posters in schools,communities and other places,and then through the strict criteria for the screening,the experimental data and the brain imaging data were collected.Among them,the behavioral data include:Eysenck Personality Questionnaire(EPQ),NEO-FFI and Sixteen Personality Factor Questionnaire(16PF).Using Germany's Siemens company Siemens Magnetom Trio3 T MR whole body imaging(MRI)system to collect high resolution 3D whole brain T1 weighted and resting-state functional magnetic resonance imaging(fMRI)data.After the completion of the scale data and the quality control of brain imaging data,atotal of 120 healthy adults aged 18-60 years were in accordance with the standard.The images were preprocessed using the Connectome Computation System(Connectome Computation System,CCS).Data analysis is adopted a method of surface-based morphology(SBM)analysis from vertex-wise and regional-wise two different scales to explore the relationship between personality traits and brain structure indexes.A general linear model(GLM)was used to examine the relationship between morphology dimensions on the brain surface and personality.The effect of gender,age,and the intracranial volume(ICV)as covariants were regressed out.Based on the study of brain structure,extract the results from structure regions,and further explore the personality traits related to the morphological changes of regional homogeneity(ReHo),using the generalized linear model to investigate the inner structure-function relationship.Results:This study attempts to explore the neurobiological mechanism of personality traits from vertex-wise and regional-wise two different scales using surface-based morphology analysis.(1)Vertex-wise morphological analysis reveals that high NEO-agreeableness was associated with large areas in the superior temporal gyrus(r= 0.471,p < 0.05,FDR corrected);high 16PF-perseverance was associated with lower volumes in the left posterior cingulate(r =-0.447,p < 0.05).(2)Based regional parcellation we examined the association between personality scores and cortical indicators.NEO-Extraversion and NEO-agreeableness showed a significant negative correlation with the volume of the left lateral occipito-temporal gyrus(r =-0.339,p <0.05)and the sulcus of the left superior parietal lobule(r =-0.377,p < 0.05).A negtive correlation showed between 16PF-perseverance,16PF-tension and the surface area of the right orbital part of the inferior frontal gyrus(r =-0.341,p < 0.05),the mean curvature of the right anterior transverse temporal gyrus(r =-0.342,p < 0.05).Moreover,16PF-self-discipline showed a significant positive correlation with the volume of the left superior frontal sulcus(r = 0.377,p < 0.05),the surface area of theleft precentral gyrus(r = 0.356,p < 0.05)and the left superior frontal sulcus(r =0.342,p < 0.05).We also performed regional functional homogeneity analysis by extracting each subject's average 2dReHo in the significant regions,which was identified in area-based morphology analysis.Results revealed that individuals who had a high NEO-extraversion had higher regional homogeneity in the left lateral occipito-temporal gyrus(r = 0.299,p < 0.05).Nevertheless,a high16PF-self-discipline,16PF-tension had lower regional homogeneity in the left superior frontal sulcus(r =-0.181,p < 0.05)and right anterior transverse temporal gyrus(r =-0.342,p < 0.05).Conclusions:This study revealing the differences in the relationship between brain morphology and personality traits on vertex-wise and regional parcellation two different scales,showing that personality features have their corresponding structural basis,of note,two methods obtained results are not overlay.Part of the variations may be due to the use of different methodology.Whole-brain analysis applies a method for calculation of the correlation between each vertex and personality traits,while using regions defined by the Destrieux atlas conducted a method for calculation the mean value of the regional vertexes.Specifically,to further interpret the regional findings we tested the linear relationship between 2dReHo in the significant regions,which was identified in area-based morphology analysis and corresponding personality traits.Study findings support the assertion that ReHo not only holds its own unique functional variability but also shares the individual variability with a wide range of cortical morphology.In sum,our findings may provide important insights into how brain affects personality traits,although the nature of this structure-function relationship is complex and should be further investigated. |
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