EPHA4 and Alzheimer disease: In fact, Eph receptor engagement and activation has been associated with several neurodegenerative disease states of the central nervous system including Alzheimer’s disease (EphA1, EphA4, EphA5, and EphB1) [44, 45, 52–55], glaucomatous degeneration of the retina (EphA2, EphB1, and EphB2) [2–5, 56–61], traumatic brain injury (EphA4, EphA6, and EphB3) [62–64], stroke (EphA4 and EphB2) [65–67], and spinal cord injury (EphA4, EphA7, and EphB2) [68–71].