Abstract: Objective To observe the change of the relative concentration of oxygenated hemoglobin in the frontal cortex during cognitive processing in patients with post-stroke depression (PSD), and to discuss the neural mechanism and changes of working memory function of PSD preliminarily.Methods From February to August, 2017, 20 patients with PSD (PSD group) and 20 patients with non-depressive (control group) were recruited. NIRSport portable functional near-infrared spectroscopy system was used to observe the change of the relative concentration of hemoglobin in the frontal cortex during the emotional face gender judgment task and "1-back" working memory task. Results Compared with the control group, the change of the relative concentration of oxygenated hemoglobin in the prefrontal cortex was significantly lower after the negative emotion faces were presented in PSD group (t=3.872, P<0.001). In the implementation of the "1-back", the change of the relative concentration of oxygenated hemoglobin in the left prefrontal cortex was significantly lower in PSD group than in the control group (t=2.475, P<0.05), however, there was no significant difference in the change in the right prefrontal cortex between two groups (t=1.773, P=0.084).Conclusion The prefrontal cortex activity decrease in patients with PSD after the negative emotion faces were presented. The left prefrontal working memory function is impaired. The patients with PSD have disorder of oxygen metabolism in the prefrontal lobe.

Key words: post-stroke depression, functional near-infrared spectroscopy, frontal cortex, neural mechanism, working memory