Thought suppression failures in combat PTSD: a cognitive load hypothesis.
ABSTRACT The present study investigated the relation between thought suppression of emotionally neutral content [i.e., Wegner's (1994) "white bear"], incidental traumatic thought intrusion, and skin conductance responses in combat-related Posttraumatic Stress Disorder (PTSD). Participants included service members who either: a) had PTSD following an Operation Iraqi Freedom deployment; b) were free of psychiatric diagnosis following deployment (Combat Equivalent), or c) were pre-deployed and without psychiatric diagnosis (Pre-Deployed). PTSD Service Members reported the greatest intrusion of combat thoughts during the suppression task and demonstrated a post-suppression rebound effect with a neutral thought. Non-specific skin conductance responses indicated that the suppression task was related to similar levels of increased sympathetic activity for both the PTSD and Pre-Deployed groups, whereas the Combat Equivalent group showed no increased activation during thought suppression. Intrusive traumatic thoughts combined with failures in neutral thought suppression may be a consequence of increased cognitive load in PTSD.
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ABSTRACT: Posttraumatic stress disorder (PTSD) is a psychiatric syndrome that develops after exposure to terrifying and life-threatening events including warfare, motor-vehicle accidents, and physical and sexual assault. The emotional experience of psychological trauma can have long-term cognitive effects. The hallmark symptoms of PTSD involve alterations to cognitive processes such as memory, attention, planning, and problem solving, underscoring the detrimental impact that negative emotionality has on cognitive functioning. As such, an important challenge for PTSD researchers and treatment providers is to understand the dynamic interplay between emotion and cognition. Contemporary cognitive models of PTSD theorize that a preponderance of information processing resources are allocated toward threat detection and interpretation of innocuous stimuli as threatening, narrowing one's attentional focus at the expense of other cognitive operations. Decades of research have shown support for these cognitive models of PTSD using a variety of tasks and methodological approaches. The primary goal of this review is to summarize the latest neurocognitive and neuroimaging research of emotion-cognition interactions in PTSD. To directly assess the influence of emotion on cognition and vice versa, the studies reviewed employed challenge tasks that included both cognitive and emotional components. The findings provide evidence for memory and attention deficits in PTSD that are often associated with changes in functional brain activity. The results are reviewed to provide future directions for research that may direct better and more effective treatments for PTSD.Frontiers in Integrative Neuroscience 01/2012; 6:89.
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ABSTRACT: In the search for ever higher output power or energy from fibre oscillators or amplifiers a nowadays mature technology relies on enlarging the fibre mode area. Broadening of the core diameter, all other things being equal, inevitably yields a multimode fibre, thereby dramatically limiting the device usefulness. Various strategies have been deployed to design and manufacture single transverse mode fibre oscillators and amplifiers, among which making use of the so-called photonic bandgap effect to restrict the modal population seems promising. Helped by efficient and reliable numerical tools the design of large mode area singlemode photonic bandgap fibres is presented. Two fibres with 20-μm and 40-μm core diameter, both of them heavily doped with Yb3+ ions, have been fabricated by the widespread modified chemical vapour deposition process and are shown to behave properly when used as the core element of either continuous wave oscillators or femtosecond amplifiers. Good output beam quality (M2 parameter spanning from 1.12 to 1.5 for the set of fibres studied) and high slope efficiency of 80% in cw oscillation regime are demonstrated. Furthermore the 40-μm core diameter fibre is shown to be resilient to tight bending down to 7.5-cm radius. The stack-and-draw process makes it easy to tailor the outer cladding so that a large numerical aperture can be reached. Subsequently, from this air-clad fibre, 500 fs 47 W pulses at 35 MHz are obtained from a two-stage chirped pulse amplification system.Optical Fiber Technology 12/2010; 16(6):419. · 1.19 Impact Factor
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ABSTRACT: The White Bear Suppression Inventory [WBSI; Wegner and Zanakos (1994)] was developed to assess the tendency to suppress unwanted thoughts. Most psychometric studies of the WBSI have included healthy students and adults with obsessive–compulsive disorder. There has been increasing interest in thought suppression in children and adolescents, especially after a traumatic event, but little is known about the psychometric properties of the WBSI for children. The aim of this research was to examine the psychometric qualities of the WBSI in a Dutch sample of children and adolescents. Two studies were conducted. First, the WBSI’s factor structure, internal consistency and test–retest stability were examined in a sample of 203 primary school children (9–13years). Second, the factor structure and content validity were assessed in 89 children and adolescents (8–18years) who attended the emergency room after a road traffic accident. Results demonstrated that the WBSI items contribute to a single factor measuring the suppression of unwanted thoughts and that the reliability is satisfactory. Associations between the WBSI and PTSD-symptoms demonstrated sufficient content validity. The findings suggest that the WBSI can appropriately be used in child and adolescent samples.Personality and Individual Differences 02/2012; · 1.86 Impact Factor