Facial emotion cognition deficits and the damage of white matter fiber tracts in the frontal lobe by diffusion tensor imaging in patients with first-episode schizophrenia

Abstract

Objective To explore facial emotion cognition character and the correlation to frontal lobe white matter fiber tracts in first-episode of schizophrenia patients in comparison with healthy control. Method The diffusion tensor imaging data were obtained from 56 patients with untreated first-episode schizophrenia and 30 healthy controls subjects. Fiber tracking was performed in the whole cerebral cortex of brain. The parameter of impairment white matter fiber tracts were obtained,such as fractional anisotropy, mean diffusivity, radial diffusivity, axial diffusivity. Computer-based facial emotion cognition test was used to evaluate difference of facial emotion identification. The correlation between ability of identifying ambiguous emotion and the parameter of impairment white matter fiber tracts, and the correlation between ability of identifying ambiguous emotion and PANSS scale were explored by linear correlation analysis. Result (1) Between patients and healthy control, there was no significant difference in the proportion of recognition as happy emotion to mixture of 50% happy emotion plus 50% angry emotion. In patients group, the number of regarding 100% happy emotion plus 0 angry emotion (9.96±2.42) and regarding 75% happy emotion plus 25% angry emotion (9.91±2.33) both as happy emotion were significantly lower than the healthy control (11.40±1.48, 11.30±1.44; t=-3.332, -3.325; all P<0.01).The number of regarding 25% happy emotion and 75% angry emotion as happy emotion(2.24±2.57), and the number of regarding 0 happy emotion and 100% angry emotion as happy emotion(1.78±2.66) were higher than healthy control(0.83±2.21, 0.70±2.02; t=2.537, 2.056; P<0.05 or P<0.01). The total response time for all images on screen was significantly longer than healthy control(t=6.441, P<0.01).(2)There are five relative serious fiber tracts impaired. Patients with schizophrenia were demonstrated lower activation in right dorsolateral frontal gyru, right inferior frontal operculum,right medial frontal gyrus, left precentral gyrus, left olfactory cortex (t=-2.993 0-2.830 0, P<0.01 or P<0.05), in comparison with healthy controls, except FA value of right inferior frontal operculum and AD value of left precentral gyrus were found higher in patients group. (3) There was no correlation between identifying facial emotion and PANSS. (4)The correlation between identifying ambiguous emotion and the parameter of impairment or white matter fiber tracts was explored by linear correlation analysis, which found FA value of left precentral gyrus positively correlated to the number of identifying happy emotion from 25% happy emotion plus 75% angry emotion (r=0.362, P=0.007), and from 0 happy emotion plus 100% angry emotion (r=0.476, P=0.000). Conclusion This study suggests that schizophrenia patients could not identify facial emotion accurately and their white matter fiber tracts in the frontal lobe are damaged significantly. The impairment of facial emotion recognition is correlated with the abnormality of white matter fiber tracts. Key words: Schizophrenia; Cognition; Frontal lobe; White matter fiber tracts