###### Abstract  
Our study aimed to identify the mechanisms of stress-induced and post-stress recovery states by evaluating voxel type and the total number of voxels activated based on Perceived Stress Scale scores. Functional MRI (fMRI) was used to measure the brain activation patterns in participants grouped into moderate- and high-stress categories. The number of activation voxels in the parahippocampal gyrus of the limbic lobe was greater in the high-stress group than in the moderate-stress group. Moreover, only the high-stress group showed the characteristic activation of the left precuneus. The moderate-stress group showed a greater number of activation voxels than the high-stress group for the occipital, frontal, and limbic lobes, while the reverse was true for the parietal lobe. In the post-stress recovery phase, the left lingual, inferior frontal, and middle frontal gyri were activated, and the number of activation voxels in these areas was greater in the high-stress group than in the moderate-stress group. The characteristic activation of the declive in the left cerebellum was observed in the moderate-stress group, whereas the activation of the right cuneus was dominant in the high-stress group. Our findings suggest that perceived stress may play an important role in determining the neural mechanisms underlying stress and post-stress recovery, providing insights into the complex interplay between the psychological and neural processes occurring in response to stress.  
stress score; stress; post-stress recovery; Perceived Stress Scale (PSS); neural mechanisms +
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highlight the significant impact of stress on brain function, but a detailed comparison of brain activation patterns based on different stress levels remains underexplored.  
The Perceived Stress Scale (PSS) is a widely used self-report questionnaire that measures subjective stress levels, providing a useful tool for categorizing individuals based on their perceived stress. Previous research indicates that higher PSS scores are associated with greater activity in brain regions involved in emotional processing, such as the amygdala and hippocampus, and decreased activity in regions associated with emotion regulation, like the prefrontal cortex [6; 7]. A longitudinal study even found that increases in PSS scores over time were linked to increased activation in the amygdala and hippocampus, further emphasizing the relationship between perceived stress and brain function [7]. While these studies shed light on the connection between stress perception and brain activation, systematic research comparing brain patterns in stress-induced and post-stress recovery states based on PSS scores is limited. Moreover, the neural mechanisms involved in resilience during the post-stress recovery state remain unclear.  
Understanding the neural mechanisms underlying both stress induction and recovery is crucial for identifying how subjective stress levels impact brain function. Grouping individuals by their PSS scores allows researchers to investigate differences in the brain activation patterns between those with moderate and high stress. By examining these patterns, researchers can identify which brain regions are more active in highly stressed individuals and explore neural correlates of resilience, which could provide insights into interventions for enhancing stress recovery. For example, identifying unique activation patterns in individuals with high versus moderate stress during recovery could highlight neural pathways that facilitate resilience.  
Therefore, this study aimed to identify the mechanism of action for each condition by examining the characteristically activated areas of the brain and the number of voxels during stress-induced and post-stress recovery states in moderate- and high-stress groups classified by their PSS scores.