For instance, in the context of a vascular dementia model, the administration of Clostridium butyricum to mice resulted in elevated levels of butyrate in both feces and brains, causing cognitive impairment and histopathological alterations in the hippocampus, along with a reduction in the expression of proteins associated with the BDNF-PI3K-AKT pathway in the hippocampus (65, 66). The gene discussed is BDNF; the disease is Cognitive impairment.