International journal of psychophysiology : official journal of the International Organization of Psychophysiology
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Fear reduction obtained during a fear extinction procedure can generalize from the extinction stimulus to other perceptually similar stimuli. Perceptual generalization of fear extinction typically follows a perceptual gradient, with increasing levels of fear reduction the more a stimulus resembles the extinction stimulus. The current study aimed to investigate whether perceptual generalization of fear extinction can be observed also after a retention interval of 24h. ⋯ Outcome measures included startle blink EMG, skin conductance, US expectancy, respiratory rate and tidal volume. On day 2 spontaneous recovery of fear was observed in US expectancy and tidal volume, but not in the other outcomes. Evidence for the retention of fear extinction generalization was present in US expectancy and skin conductance, but a perceptual gradient in the retention of generalized fear extinction could not be observed.
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Int J Psychophysiol · Dec 2015
Behavioral and central correlates of contextual fear learning and contextual modulation of cued fear in posttraumatic stress disorder.
Patients with posttraumatic stress disorder (PTSD) show persistent fear responses to trauma cues in contexts in which these cues no longer predict danger. This might be related to deficient context and enhanced cue conditioning. To test this hypothesis, we examined context conditioning directly followed by a cue conditioning phase against the background of the previously conditioned context in 12 patients with PTSD, 14 traumatized control subjects without PTSD and 11 matched never-traumatized controls. ⋯ This study provides evidence for a dissociation of brain responses and contingency awareness in PTSD which represents impaired context learning and a deficient contextual modulation of cue-related associations. In addition, extinction and extinction recall were impaired in PTSD. These changes were related to PTSD symptoms and suggest that contextual learning deficits may contribute to PTSD.