Fear Conditioning and Extinction Task
Objective: To demonstrate that context-dependent human extinction memory is mediated by ventromedial prefrontal cortex and hippocampal network activity, where extinction memory recall is facilitated by contextual stimuli present during extinction training
Protocol Steps
Fear Conditioning Phase
Participants learn to associate a conditioned stimulus (CS) with an unconditioned stimulus (UCS), establishing a CS-UCS memory trace
Note: This phase establishes the initial fear memory that will be extinguished in subsequent phases
View evidence from paper
“In fear extinction, an animal learns that a conditioned stimulus (CS) no longer predicts a noxious stimulus [unconditioned stimulus (UCS)] to which it had previously been associated”
Extinction Training in Context 1
Participants learn that the CS no longer predicts the UCS in a specific extinction context, creating a new CS-noUCS memory trace that competes with the initial fear memory
Note: Extinction creates context-dependent memory; contextual stimuli present during extinction training facilitate recall of extinction memory
View evidence from paper
“Extinction creates a new CS–noUCS memory trace, competing with the initial fear (CS–UCS) memory. Recall of extinction memory and, hence, CR inhibition at later CS encounters is facilitated by contextual stimuli present during extinction training”
CS Presentation in Extinction Context
CS is presented in the extinction context where extinction training occurred, measuring ventromedial prefrontal cortex and hippocampal engagement
Note: CS-evoked engagement of VMPFC and hippocampus is context-dependent, being expressed in extinction context
View evidence from paper
“after extinction, a CS-evoked engagement of human ventromedial prefrontal cortex (VMPFC) and hippocampus is context dependent, being expressed in an extinction, but not a conditioning, context”
CS Presentation in Conditioning Context
CS is presented in the original conditioning context to test context-dependency of extinction memory recall
Note: VMPFC and hippocampal engagement should not be expressed in the conditioning context, demonstrating context-dependent extinction memory
View evidence from paper
“a CS-evoked engagement of human ventromedial prefrontal cortex (VMPFC) and hippocampus is context dependent, being expressed in an extinction, but not a conditioning, context”