In addition, the injection of interferon-γ and poly(I:C), a Toll-like receptor-3 (TLR3) agonist mimicking the effect of HCV double-strand RNA, caused depression-like symptoms, and the proinflammatory genes were synergistically induced in the hippocampus and prefrontal cortex [105]. This evidence concerns the gene TLR3 and depressive symptom measurement.