TLR4 and neurodegenerative disease: It is associated with both neuroprotective (Tahara et al., 2006; Marsh et al., 2009) and neurotoxic (Tang et al., 2008; Abate et al., 2010) effects, neuropathic pain (Lewis et al., 2012), neurodegenerative diseases (Heneka et al., 2014) developmental and adult neuroplasticity (Okun et al., 2011), and adult hippocampal neurogenesis (Rolls et al., 2007); loss of TLR4 increases adult NPC proliferation and neuronal differentiation.