FOS and ischemic stroke: Furthermore, although expression of immediate early genes such as c-FOS can become induced in response to damage such as ischemic stroke, we found no evidence for induction of glial genes such as GFAP and S100B that mark astrocyte activation in response to stroke and other forms of damage (Choudhury and Ding, 2016; Ding, 2014; Dirnagl et al., 1999; Kajihara et al., 2001; Pekny and Nilsson, 2005).