Multiple stimuli induce expression of IEGs that include trophic factors downstream of receptor tyrosine kinases (RTKs, e.g., EGFR, TrkA, TrkB), calcium channels (e.g., NMDAR), neurotransmitters (glutamine, dopamine), and viral infection (Bahrami and Drabløs, 2016; Minatohara et al., 2016; Gallo et al., 2018). This evidence concerns the gene EGFR and viral infectious disease.