Role of NMDA receptors and MAP kinase in the amygdala in extinction of fear: clinical implications for exposure therapy.

Infusions into the amygdala (a brain area essential for excitatory fear conditioning) of either NMDA receptor antagonists or inhibitors of the NMDA receptor-linked mitogen activated protein kinase cascade block extinction learning. Conversely, the NMDA receptor agonist D-cycloserine facilitates extinction after either systemic administration or intra-amygdala infusion. Because therapeutic interventions based on extinction procedures are commonly used to treat fear disorders, and because D-cycloserine is a widely available and safe compound, D-cycloserine or similar agents might be usefully combined with traditional extinction-based approaches in the treatment of clinical fear.