PRRT2 and age: Given that the abnormal glycolipid metabolism was associated with cognitive dysfunction (Arend et al., 2018; Qiu et al., 2022), the changes in the expression of mm9_circ_009789, mm9_circ_004229, Prkcb and Zbtb4 in our POCD model suggests that the PKC signaling pathway, neural cell apoptosis and glycolipid metabolism pathway may be regulated by mm9_circ_009789 and mm9_circ_004229-associated-ceRNA networks and involved in age-related POCD neuropathogenesis.