Functional Inactivation of the Amygdala before But Not after Auditory Fear Conditioning Prevents Memory Formation Ann E. Wilensky, Glenn E. Schafe, and Joseph E. LeDoux W. M. Keck Foundation Laboratory of Neurobiology, Center for Neural Science, New York University, New York, New York JNS, 1999

About the author Joseph E. LeDoux Professor of NYU His work has focused on the study of the neural basis of emotions, especially fear and anxiety. His work has elaborated in detail how the brain detects and responds to danger, and learns and forms memories about threats.

Introduction Theory 1: based on studies using inhibitory avoidance training, proposes that the amygdala modulates the strength of fear learning, and post- training amygdala manipulations interfere with memory consolidation. Theory 2: based on studies using Pavlovian fear conditioning, hypothesizes that fear learning occurs in the amygdala, and post-training manipulations after acquisition will not affect memory consolidation.

Inhibitory avoidance training

Method Subjects: 22 male SD rats For experimental group, muscimol (4.4 nmol/side in 0.5 ul) was injected, and saline as control.

Experiment 1

Result

Experiment 2

Result

Conclusion Although pre-training injections of muscimol blocked auditory Pavlovian fear conditioning, immediate post-training injections had no effect.