Biological psychology
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Biological psychology · Feb 2013
Deficient safety learning characterizes high trait anxious individuals.
Trait anxiety is a well-established risk factor for developing anxiety disorders, but evidence for abnormal associative fear learning in high trait anxious (HTA) individuals is inconclusive. In part, this may due to limitations in the scope and measures used to assess fear learning. The current study therefore assessed fear learning across multiple response domains and multiple test phases in a two-day discriminative fear-conditioning paradigm. ⋯ HTA participants showed stronger fear on the startle response and distress ratings to the safety (CS(-)) but not to the threat stimulus (CS(+)) during acquisition, along with impaired extinction and re-extinction. Trait anxiety did not affect skin conductance responses and effects on UCS-expectancy were limited. We conclude that high trait anxiety may be characterized by deficient safety learning which in turn may promote persistent and generalized fear responses.
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Biological psychology · Feb 2013
No effect of trait anxiety on differential fear conditioning or fear generalization.
Previous studies have shown that individuals with anxiety disorders exhibit deficits in fear inhibition and excessive generalization of fear, but little data exist on individuals at risk from these disorders. The present study examined the role of trait anxiety in the acquisition and generalization of fear in 126 healthy participants selected on the basis of their trait-anxiety scores. ⋯ Contrary to our hypotheses, trait anxiety did not have any effect either on the acquisition or the generalization of fear. Our results suggest that these fear conditioning processes are not impaired in individuals at risk from anxiety.
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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.
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Biological psychology · Oct 2012
Should it matter when we record? Time of year and time of day as factors influencing frontal EEG asymmetry.
Resting frontal encephalographic (EEG) asymmetry, often conceptualized as a trait marker for depression, is influenced by occasion-specific factors, including time of year and the time of day of the recording session as demonstrated recently (Peterson and Harmon-Jones, 2009). The current study examined the influence of seasonal and chronological variables on resting frontal asymmetry, and also assessed whether different reference montages or surface transformations were equally susceptible to these influences. ⋯ Time awake at recording, however, was an important moderating variable of the relationship between photoperiod and time of day. EEG asymmetry scores based on current-source density (CSD) transformed data, however, appeared less vulnerable to these influences, providing further evidence to suggest that the CSD transform may be advantageous for examining stable trait estimates of frontal EEG asymmetry.