With the overall aim of exploring the potential pharmaceutical use of B. breve A1 for the treatment of cognitive deficits in PD, in the present study, we examined the effects of B. breve A1 on contextual fear extinction to clarify whether administration of B. breve A1 can restore the facilitation of hippocampal memory extinction in PD mice. The gene discussed is PPIB; the disease is Cognitive impairment.