TNF and Anxiety: 22 Also, LPS is reported to upregulate the expression of TNF-α, IL-1β via activating microglia.70,71 Notably, these pro-inflammatory cytokines have been reported to induce anxiety-like behaviors.16,17 Thus, we proposed that disturbance of gut microbiota may decrease 5-HT levels and induce neuroinflammation in the amygdala, which jointly contribute to anxiety behaviors induced by T. gondii infection.