Reinstatement of conditioned fear in humans is context dependent and impaired in amnesia.

A contextual reinstatement procedure was developed to assess the contributions of environmental cues and hippocampal function in the recovery of conditioned fear following extinction in humans. Experiment 1 showed context specificity in the recovery of extinguished skin conductance responses after presentations of an auditory unconditioned stimulus. Experiment 2 demonstrated that fear recovery did not generalize to an explicitly unpaired conditioned stimulus. Experiment 3 replicated the context dependency of fear recovery with a shock as an unconditioned stimulus. Two amnesic patients failed to recover fear responses following reinstatement in the same context, despite showing initial fear acquisition. These results extend the known functions of the human hippocampus and highlight the importance of environmental contexts in regulating the expression of latent fear associations.