Hippocampal resting-state functional connectivity with the mPFC and DLPFC moderates and mediates the association between education level and memory function in subjective cognitive decline

Objective:This study aims to determine the relationship between education level,memory function,and hippocampus functional and structural alterations in subjective cognitive decline(SCD).Methods:Seventy-five participants with SCD were divided into high education(HE)and low education(LE)level groups.A Wechsler Memory Scale-Chinese Revision test and functional and structural MRI were performed within 1 week after participant recruitment.The bilateral hippocampus resting-state functional connectivity(rsF C),gray matter volume(GMV)of brain regions identified by rsF C analysis,and moderating and mediating effects were assessed.Results:Compared with the LE group,HE individuals showed 1)higher memory quotient(MQ)and Digit Span subscore,2)decreased hippocampal rs FC with the right medial prefrontal cortex(mPFC)and dorsolateral prefrontal cortex(DLPFC),and 3)increased GMV in the right mP FC and DLPFC.The bilateral hippocampus-right DLPFCrs FC significantly associated with the MQ and the bilateral hippocampus-right m PFCrs FC with the Digit Span subscore in each group.The bilateral hippocampus-right DLPFCrsFC moderated the relationship between the education level and MQ.The bilateral hippocampus-right mP FC rsF C mediated the relationship between the education level and Digit Span subscore in all subjects.Conclusion:The hippocampal rsF C with the right mP FC and DLPFC contributes to the education level effect on memory function in SCD.