Table 5.

Relationship between probiotic and cognitive function in animal studies.

Study	Microorganism	Intervention targets	Impact
Sun et al. (2020)	Clostridium butyricum	APP/PS1 mice	Butyrate treatment reduces the levels of CD11b and COX-2, and suppresses phosphorylation of NF-κB p65 in the Aβ-induced BV2 microglia.
Ou et al. (2020)	Akkermansia muciniphila	APP/PS1 mice	Akk promoted the reduction of Aβ 40–42 levels in the cerebral cortex of APP/PS1 mice, shortened the study time and improved the completion rate in Y-maze tests.
Yang et al. (2020)	Bifidobacterium lactis, Lactobacillus casei, Bifidobacterium bifidum and Lactobacillus acidophilus	SAMP8 mice	The probiotic improved cognitive function, and that its mechanism is associated with inhibition of both TLR4-and RIG-I-mediated NF-κB signaling pathway and inflammatory responses in the APP/PS1 mouse.
Cao J. et al. (2021)	Bifidobacterium Lactis Probio-M8	APP/PS1 mice	Probio-M8 reduced Aβ plaque burden in the whole brain and could alleviate cognitive impairment in the APP/PS1 mouse.
Kobayashi et al. (2017)	Bifidobacterium breve strain A1	AD mice	The consumption of B. breve A1 suppressed the hippocampal expressions of inflammation and immune-reactive genes that are induced by amyloid-β.