Source Paper
Active Avoidance Learning Requires Prefrontal Suppression of Amygdala-Mediated Defensive Reactions
Justin M. Moscarello, Joseph E. LeDoux
Journal of Neuroscience • 2013
Active Avoidance Learning
Objective: Test the hypothesis that the instrumental component of active avoidance training recruits infralimbic prefrontal cortex (ilPFC) to inhibit central amygdala (CeA)-mediated Pavlovian reactions during signaled active avoidance learning
Protocol Steps
Signaled Active Avoidance Training Paradigm
Subjects are trained in a signaled active avoidance paradigm where they learn to prevent an aversive outcome by performing a learned behavior during the presentation of a conditioned cue
Note: This complex form of conditioning involves both Pavlovian and instrumental components which produce competing behavioral responses that must be reconciled for successful avoidance
View evidence from paper
“Signaled active avoidance (AA) paradigms train subjects to prevent an aversive outcome by performing a learned behavior during the presentation of a conditioned cue”
Pretraining Lesions of ilPFC
Lesions of infralimbic prefrontal cortex (ilPFC) are performed prior to training to test their effects on avoidance behavior and conditioned freezing
Note: Pretraining lesions of ilPFC increased conditioned freezing while causing a corresponding decrease in avoidance
View evidence from paper
“Pretraining lesions of ilPFC increased conditioned freezing while causing a corresponding decrease in avoidance”
Pretraining Lesions of CeA
Lesions of central amygdala (CeA) are performed prior to training to test their effects on avoidance behavior and conditioned freezing
Note: Lesions of CeA produced opposite effects, reducing freezing and facilitating avoidance behavior
View evidence from paper
“lesions of CeA produced opposite effects, reducing freezing and facilitating avoidance behavior”
Pharmacological Inactivation of ilPFC
Pharmacological inactivation experiments are conducted to demonstrate that ilPFC is relevant to both acquisition and expression phases of active avoidance learning
Note: Inactivation experiments demonstrated that ilPFC is relevant to both acquisition and expression phases of AA learning
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“Pharmacological inactivation experiments demonstrated that ilPFC is relevant to both acquisition and expression phases of AA learning”
Testing Generalization of ilPFC-Mediated Suppression
Inactivation experiments reveal that active avoidance produces an ilPFC-mediated diminution of Pavlovian reactions that extends beyond the training context, even when the conditioned stimulus is presented in an environment that does not allow the avoidance response
Note: This demonstrates generalization of the suppression effect across different environments
View evidence from paper
“AA produces an ilPFC-mediated diminution of pavlovian reactions that extends beyond the training context, even when the conditioned stimulus is presented in an environment that does not allow the avoidance response”
Protein Synthesis Inhibitor Injection into ilPFC
A protein synthesis inhibitor is injected into infralimbic prefrontal cortex to test its effects on active avoidance learning
Note: Injection of a protein synthesis inhibitor into ilPFC impaired active avoidance learning
View evidence from paper
“injection of a protein synthesis inhibitor into either ilPFC or CeA impaired or facilitated AA, respectively”
Protein Synthesis Inhibitor Injection into CeA
A protein synthesis inhibitor is injected into central amygdala to test its effects on active avoidance learning
Note: Injection of a protein synthesis inhibitor into CeA facilitated active avoidance learning, showing that avoidance training produces two opposing memory traces in these regions
View evidence from paper
“injection of a protein synthesis inhibitor into either ilPFC or CeA impaired or facilitated AA, respectively, showing that avoidance training produces two opposing memory traces in these regions”