Neural association between mental symptoms and facial emotion recognition in deficit schizophrenia: an fNIRS study

Abstract Background The dysfunction of the prefrontal cortex (PFC) is closely related to the emotion recognition deficits in schizophrenia. Compared with the non-deficit schizophrenia (NDSZ), deficit schizophrenia (DSZ) has a more severe deficit in emotion recognition; however, the underlying neurobiological mechanism is unclear. Thus, this study aimed to investigate PFC activation patterns and their correlations with clinical scale scores during facial emotion recognition (FER) between the DSZ and NDSZ using functional near-infrared spectroscopy (fNIRS). Methods This study included 38 DSZ patients, 49 NDSZ patients, and 39 healthy controls (HCs). FER was evaluated using a standardized visual emotion discrimination task, while PFC activation was monitored via fNIRS. To identify channels(CHs) with statistically significant differences in oxygenated hemoglobin (HbO) changes across the three groups, we performed one-way ANOVA followed by post hoc Bonferroni tests for pairwise comparisons. These analyses explored the relationship between HbO concentration changes in the PFC and clinical scale scores during FER tasks. Results During anger, sadness, contempt, and happiness recognition tasks, the DSZ group showed significantly reduced HbO activation in the dorsolateral prefrontal cortex (DlPFC; Brodmann area 9, BA9) and the frontopolar cortex(BA10), compared with the NDSZ group. Similarly, decreased activation patterns were observed in BA9 and BA10 in the DSZ group during anger and happiness recognition tasks compared with the HCs. Furthermore, during contempt recognition, reduced activation was found in BA9 compared with the HCs. Correlation analyses revealed moderate negative associations (i.e., an inverse relationship) between activation levels in these prefrontal regions (BA9/BA10) and negative symptoms (i.e., diminution of emotional expression and motivation) scores in DSZ patients across these four emotion tasks. However, no significant correlations were found in NDSZ patients and HCs. Conclusion Compared with the NDSZ patients, DSZ patients exhibited more severe FER impairments, demonstrating a different cognitive deficit pattern. Clinical trial number Not applicable.