Upon brain injury or infection, microglia transform to an activated state and secrete neurotoxic mediators, such as reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-α), and interleukin-1β (IL-1β; Belarbi et al., 2011; Krishnaswamy and Cooper, 2012; Mishra et al., 2012; Yang et al., 2013) which have harmful effects including disruption of neuronal function/synaptic transmission and neuronal oxidative stress/degeneration resulting in neuronal damage. The gene discussed is TNF; the disease is infection.