ACQUISITION OF CONTEXTUAL PAVLOVIAN FEAR CONDITIONING IS BLOCKED BY APPLICATION OF AN NMDA RECEPTOR ANTAGONIST D,L-2-AMINO-5-PHOSPHONOVALERIC ACID TO THE BASOLATERAL AMYGDALA

Rats, with chronic cannula placed bilaterally in the amygdala, receive d infusions of the N-methyl-D-aspartate (NMDA) receptor antagonist D,L -2-amino-5-phosphonovaleric acid (APV) before contextual Pavlovian fea r conditioning. Administration of APV to the basolateral nucleus preve nted acquisition of fear. Central nucleus infusions had no effect. It is concluded that an NMDA-mediated process near the basolateral region of the amygdala (e.g., lateral or basolateral nucleus) is essential f or the learning of fear.