Neuroscience of emotional memory and posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is now widely recognized in Japan followingthe Kobe earthquake and the Tokyo subway sarin poisoning in 1995. Wider awarenessof this disorder has resulted in an increase in the number of patients presentingwith the core symptoms of PTSD, which include: (1) persistent increased arousal;(2) reexperience of a traumatic event; (3) persistent avoidance of stimuli associatedwith the trauma; and (4) numbing of general responsiveness.We have conducted studies to elucidate the biological mechanisms that causethese clinical symptoms and deeply engrain memories associated with highly emotionalevents (emotional memory). We used animal models to target a phenomenoncalled neurogenesis and the dynamics of a gene transcription factor called cyclicAMP-response element binding (CREB) protein in the hippocampus. This chapterdiscusses the results of some of our studies.