IGF-1, expressed in the CNS by microglia/macrophages, astrocytes, and neurons (54, 63), enhances axon outgrowth of corticospinal motor neurons in vitro and in the developing CNS (64), and high serum IGF-1 levels just after the onset of ischemic stroke are associated with better neurological recovery in humans (65). This evidence concerns the gene IGF1 and ischemic stroke.