Objective To investigate the relationship between brain structural networks and gut micro-biota in patients with mild cognitive impairment associated with Parkinson's disease(PD-MCI),and the impact on cognitive function by neuroimaging and intestinal microbiology techniques.Methods 29 cases of patients with PD-MCI and 17 cases of PD patients with normal cognitive function(PD-NC)were enrolled.MRI T1-weighted and diffusion tensor imaging were collected for graph theory analysis,and fecal samples were analyzed using 16s DNA sequencing.Partial correlation analysis assessed relationships among differential bacteria,structural network prop-erties,and cognitive scale scores,finally followed by mediation effect analysis.Results In PD patients,the abundance of Prevotellaceae,Alloprevotella,and UCG-10 bacteria was positively correlated with language and memory cognitive domains,while the abundance of UCG-010 showed a negative correlation with executive function.Additionally,the gut microbiota also was associated with several distinct brain structural network node characteristics.Mediation analysis indicated that Prevotellaceae's effect on logical memory was mediated by the node degree in the right opercular inferior frontal gyrus(IE=0.074,95%CI:0.21～0.001,P=0.046).Conclusions PD-MCI patients showed distinct gut microbiota and brain network features compared to PD-NC patients.The association and the me-diation analysis of gut microbiota with brain networks and cognitive impairment suggests a role for Prevotellaceae in brain network alterations related to MCI,highlighting the gut-brain axis's potential influence on cognition.

Objective To investigate the relationship between brain structural networks and gut micro-biota in patients with mild cognitive impairment associated with Parkinson's disease(PD-MCI),and the impact on cognitive function by neuroimaging and intestinal microbiology techniques.Methods 29 cases of patients with PD-MCI and 17 cases of PD patients with normal cognitive function(PD-NC)were enrolled.MRI T1-weighted and diffusion tensor imaging were collected for graph theory analysis,and fecal samples were analyzed using 16s DNA sequencing.Partial correlation analysis assessed relationships among differential bacteria,structural network prop-erties,and cognitive scale scores,finally followed by mediation effect analysis.Results In PD patients,the abundance of Prevotellaceae,Alloprevotella,and UCG-10 bacteria was positively correlated with language and memory cognitive domains,while the abundance of UCG-010 showed a negative correlation with executive function.Additionally,the gut microbiota also was associated with several distinct brain structural network node characteristics.Mediation analysis indicated that Prevotellaceae's effect on logical memory was mediated by the node degree in the right opercular inferior frontal gyrus(IE=0.074,95%CI:0.21～0.001,P=0.046).Conclusions PD-MCI patients showed distinct gut microbiota and brain network features compared to PD-NC patients.The association and the me-diation analysis of gut microbiota with brain networks and cognitive impairment suggests a role for Prevotellaceae in brain network alterations related to MCI,highlighting the gut-brain axis's potential influence on cognition.