The ability of PACAP to stimulate the expression of genes such as BDNF, SLC16A7, NEUROD1, VEGFA, HOMER 1, or DBI/ACBP when administered either just after the occlusion or at later time points, highlights the ability of PACAP to not only block stroke induced apoptosis but also to promote subsequent synaptic plasticity and brain regeneration. The gene discussed is HOMER1; the disease is Stroke.