At least four members of the Eph receptor family including EphA4, EphB1, EphB2, and EphB3 are highly expressed in the prefrontal cortex, hippocampus and amygdala, whose functions are closely related to emotional and cognitive disorders, such as depression, anxiety, and memory deficits (Liebl et al., 2003). The gene discussed is EPHB2; the disease is major depressive disorder.