TLR4 and Cognitive impairment: FCF alleviated SD-induced cognitive deficits, reversed gut microbiota dysbiosis (increased beneficial bacteria like Lactobacillus, reduced harmful ones like Desulfovibrio), promoted short-chain fatty acids production, improved colonic histopathology and intestinal barrier function, reduced serum lipopolysaccharide, inhibited glial cell activation and TLR4/NF-κB signaling, and regulated neurotransmitters.