Obstructive sleep apnea (OSA), recognized as a highly prevalent sleep breathing disorder with severe complications, features a complex etiology. Poor understanding of disease pathogenesis limits the overall efficacy of interventions. Studies have found that upregulation of 5-HT7 expression in the lateral hypothalamus (LH) could reduce arousal threshold (ArTH) and induce an inhibitory effect to the respiratory central, which was associated with hypoxic stimulation. Therefore, the investigators speculate that the structural/functional abnormalities of the arousal-respiratory neural circuit, mediated by LH5-HT7, may play an important role in the pathogenesis of OSA. To verify the hypothesis, the investigators will compare the ArTH and the brain network presenting by multimodal MRI in normal individuals, snoring individuals, and OSA patients, to reveal the correlation between arousal dysregulation and the structure/function of LH regions; compare the changes of ArTH and brain network in OSA patients with low ArTH before and after CPAP treatment, to verify the interaction between hypoxia and arousal dysregulation, as well as whether the damaging performance of the arousal-respiratory brain regulation area in OSA patients can be partially reversed by relieving hypoxia. Above all, the joint application B team will further analyze the LH5-HT7 neural mechanism in the pathogenesis of OSA.