PARP1 and Cognitive impairment: Some studies have suggested that PARP-1 causes cognitive impairment in AD patients for two reasons, one of which is because the loss of neuronal nucleoli PARP-1 may lead to synaptic plasticity defects, resulting in cognitive impairment; in the other possibility, in late stages of AD, PARP-1 may be overactivated and cause brain cell death (Zeng et al., 2016; Mao and Zhang, 2021).