Biological psychology
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Biological psychology · Jan 2013
Comparative StudyLearning to fear obstructed breathing: comparing interoceptive and exteroceptive cues.
The present study investigated interoceptive fear conditioning (IFC) to an interoceptive and exteroceptive conditional stimulus (CS) with a severe respiratory load applied for 30s as the unconditional stimulus (US). CSs were another, weak respiratory load in the intero-IFC study (N=74), and a neutral picture in the extero-IFC study (N=42). CSs preceded the US in the paired groups, whereas the unpaired groups received the same number of unpaired CSs and USs. ⋯ In the intero-IFC study, the CS-load was associated with larger startle blinks and a smaller decrease in respiratory rate and tidal volume in the paired compared to the unpaired group. In the extero-IFC study, the CS-picture evoked an increase in tidal volume and self-reported fear only in the paired group. In addition, startle potentiation during the CS-picture was greater for the paired than for the unpaired group.
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Recent studies on fear generalization have demonstrated that fear-potentiated startle and skin conductance responses to a conditioned stimulus (CS) generalize to similar stimuli, with the strength of the fear response linked to perceptual similarity to the CS. The aim of the present study was to extend this work by examining neural correlates of fear generalization. ⋯ We then replicated this effect in a larger independent sample (N=25). Activation in the insula, anterior cingulate, right supplementary motor cortex and caudate increased reactivity as generalization stimuli (GS) were more similar to the CS, consistent with participants' overall ratings of perceived shock likelihood and pupillary response to each stimulus.