Another gene that was found to be expressed in the adult prefrontal cortex in rats in response to an adversity in early life is the brain-derived neurotrophic factor (BDNF) gene playing a crucial role in the neural and behavioral plasticity and in development of various psychiatric disorders related to adversity early in life, such as depression, bipolar disorder, autism, and schizophrenia [40]. The gene discussed is BDNF; the disease is major depressive disorder.