GJA1 and ischemia: Butler et al. (2002) linked the augmentation of astrocyte activation with the appearance of degenerating pyramidal neurons (Butler et al., 2002), which likely occurred as a result of the astrocytic release of neurotoxic molecules (Phatnani and Maniatis, 2015). The time course of Cx43-positive cell numbers in the CA1 region differs from the one in the cortex: the boost starts from the first day and the rise is even stronger 1 week after ischemia (Haupt et al., 2007).