279. CLINICAL FEATURES AND NEURAL SUBSTRATES UNDERLYING HUMOR PROCESSING IN PATIENTS WITH FIRST EPISODE SCHIZOPHRENIA

Abstract Background Patients with chronic schizophrenia present difficulties in humor recognition and appreciation, but the clinical features and neural mechanism of humor processing in the early stage of illness remains unclear. Aims & Objectives This study aimed to elucidate clinical features and neural substrates underlying humor processing in patients with first episode schizophrenia (FES). Method This study recruited 45 patients with FES and 44 matched healthy controls. Participants completed the Picture Humor Processing Task (HPT-p) and the Video Humor Processing Task (HPT-v) which tapped into humor comprehension and appreciation. 40 of the patients and 31 of the controls completed a fMRI verbal humor processing paradigm comprising 96 stories, half for funny punch-line condition and the other half for unfunny condition. Signal detection theory (SDT) analysis was used to calculate d’ and β values which represented sensitivity and inner criteria for humor signals respectively. The funny-unfunny contrast was analyzed to identify the brain regions related with humor processing. d’ and β values were put into the imaging regression analysis. Results In HPT-p, patients with FES showed higher false alarm rate (p = 0.048) while comparable sensitivity of humor signals (d' value) and intrinsic evaluation criterion (β value) compared to healthy controls. In HPT-v, patients with FES showed lower within-group coherence in funniness rating (p = 0.023). In verbal humor processing, patients with FES showed significantly lower sensitivity (d' value). At the neural level, patients with FES hypo-activated in ventral medial prefrontal cortex (vmPFC) and anterior cingulate cortex (ACC) while hyper-activated in middle temporal gyrus (MTG) and superior temporal gyrus (STG) compared to controls. In addition, activity in vmPFC and ACC was positively associated with d’ and β values, while activity in STG was positively associated with β values in the clinical group. Discussion & Conclusions Patients with FES exhibited decreased sensitivity to humor signals and made more misjudgment, indicating impairment of humor recognition. However, they showed intact humor appreciation. At the neural level, hypo-activation in frontal regions and hyper-activation in temporal regions were associated with the humor processing deficits in FES.