International journal of psychophysiology : official journal of the International Organization of Psychophysiology
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Int J Psychophysiol · Aug 2016
Distinction in EEG slow oscillations between chronic mild traumatic brain injury and PTSD.
Spectral information from resting state EEG is altered in acute mild traumatic brain injury (mTBI) and in disorders of consciousness, but there is disagreement about whether mTBI can elicit long term changes in the spectral profile. Even when identified, any long-term changes attributed to TBI can be confounded by psychiatric comorbidities such as PTSD, particularly for combat-related mTBI where postdeployment distress is commonplace. ⋯ Results support the idea that long-term neurophysiological effects of mTBI share some features with states of reduced arousal and cognitive dysfunction, suggesting a role for EEG in tracking the trajectory of recovery and persisting vulnerabilities to injury. Additionally, results suggest that EEG power reflects distinct pathophysiologies for current PTSD and chronic mTBI.
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Int J Psychophysiol · Jan 2016
Meditation and attention: A controlled study on long-term meditators in behavioral performance and event-related potentials of attentional control.
Meditation practice involves attention regulation, and thus is thought to facilitate attention control mechanisms. Studies on meditation techniques using a behavioral measurement of the Attention Network Test (ANT) have shown enhanced attention control, but neural features remain unknown. ⋯ The P3 amplitude in the parietal area remained constant in the congruent and incongruent target conditions among meditators, indicating a higher parietal P3 amplitude during the incongruent target condition relative to matched controls. The findings that meditators exhibited fewer error responses on the ANT and a lack of parietal P3 modulation irrespective of reaction time are discussed in the context of attentional resource allocation.
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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.
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Int J Psychophysiol · Jul 2015
Reinstatement of contextual anxiety in humans: Effects of state anxiety.
After successful extinction of conditioned fear, the presentation of an unsignaled unconditioned stimulus (US) leads to return of fear, thus, the previously extinguished conditioned stimulus (CS) triggers fear responses again. Human studies on such reinstatement processes are still inconclusive. Some revealed a general increase of fear reactions, both to the fear (CS+) and the safety stimulus (CS-), whereas other studies discovered a differential return of fear with enhanced fear responses to the CS+ only. ⋯ Only the reinstatement group showed a differential return of contextual anxiety as measured by fear-potentiated startle and anxiety ratings. Interestingly, the reinstatement of fear-potentiated startle was additionally influenced by state anxiety. Conclusively, an anxious state before an unsignaled aversive event might favor a return of contextual anxiety.