Reducing analogue trauma symptoms by computerized reappraisal training - considering a cognitive prophylaxis?

BACKGROUND AND OBJECTIVES: Distressing intrusions are a hallmark of posttraumatic stress disorder (PTSD). Dysfunctional appraisal of these symptoms may exacerbate the disorder, and conversely may lead to further intrusive memories. This raises the intriguing possibility that learning to 'reappraise' potential symptoms more functionally may protect against such symptoms. Woud, Holmes, Postma, Dalgleish, and Mackintosh (2012) found that 'reappraisal training' when delivered after an analogue stressful event reduced later intrusive memories and other posttraumatic symptoms. The present study aimed to investigate whether reappraisal training administered before a stressful event is also beneficial. METHODS: Participants first received positive or negative reappraisal training (CBM-App training) using a series of scripted vignettes. Subsequently, participants were exposed to a film with traumatic content. Effects of the CBM-App training procedure were assessed via three distinct outcome measures, namely: (a) post-training appraisals of novel ambiguous vignettes, (b) change scores on the Post Traumatic Cognitions Inventory (PTCI), and (c) intrusive symptom diary. RESULTS: CBM-App training successfully induced training-congruent appraisal styles. Moreover, those trained positively reported less distress arising from their intrusive memories of the trauma film during the subsequent week than those trained negatively. However, the induced appraisal bias only partly affected PTCI scores. LIMITATIONS: Participants used their own negative event as a reference for the PTCI assessments. The events may have differed regarding their emotional impact. There was no control group. CONCLUSIONS: CBM-App training has also some beneficial effects when applied before a stressful event and may serve as a cognitive prophylaxis against trauma-related symptomatology.

Ameliorating intrusive memories of distressing experiences using computerized reappraisal training.

The types of appraisals that follow traumatic experiences have been linked to the emergence of posttraumatic stress disorder (PTSD). Could changing reappraisals following a stressful event reduce the emergence of PTSD symptoms? The present proof-of-principle study examined whether a nonexplicit, systematic computerized training in reappraisal style following a stressful event (a highly distressing film) could reduce intrusive memories of the film, and symptoms associated with posttraumatic distress over the subsequent week. Participants were trained to adopt a generally positive or negative poststressor appraisal style using a series of scripted vignettes after having been exposed to highly distressing film clips. The training targeted self-efficacy beliefs and reappraisals of secondary emotions (emotions in response to the emotional reactions elicited by the film). Successful appraisal induction was verified using novel vignettes and via change scores on the post traumatic cognitions inventory. Compared with those trained negatively, those trained positively reported in a diary fewer intrusive memories of the film during the subsequent week, and lower scores on the Impact of Event Scale (a widely used measure of posttraumatic stress symptoms). Results support the use of computerized, nonexplicit, reappraisal training after a stressful event has occurred and provide a platform for future translational studies with clinical populations that have experienced significant real-world stress or trauma.

TMS over right posterior parietal cortex induces neglect in a scene-based frame of reference.

Although damage to right posterior parietal cortex (RPPC) produces bias in line bisection, Karnath et al. [Karnath, H.-O., Berger, M. F., Küker, W., & Rorden, C. (2004). The anatomy of spatial neglect based on voxelwise statistical analysis: A study of 140 patients. Cerebral Cortex, 14, 1164-1172] claim that it plays little role in spatial neglect, which is better measured by target cancellation. We used a detection task (approximating cancellation in requiring detection) to investigate this claim by compromising the parietal cortex with transcranial magnetic stimulation (TMS). Two outline shapes, one on each side of fixation, were briefly displayed before a mask. The target was a discontinuity in the left or right of the outline of one of these perceptual objects. Subjects indicated position or absence of target as fast as possible. Stimulus-mask onset asynchrony was adjusted individually to yield 75% detection. TMS was delivered over left posterior parietal cortex (LPPC), RPPC and Vertex, with Sham TMS over RPPC as a baseline control. Target detection was near ceiling and fastest at central positions and worst and slowest at the far right. Detection was significantly reduced at the far left position by TMS over RPPC. No other effects were obtained and latency was not affected by TMS. Disruption of RPPC by TMS does produce left neglect as measured by detection. Given the pattern of performance and since it was disrupted on one side of the display rather than on one side of each shape, attention and neglect were in a scene-based rather than object-based reference frame.

A behavioural and functional neuroimaging investigation into the effects of nicotine on sensorimotor gating in healthy subjects and persons with schizophrenia.

RATIONALE: Schizophrenia patients display an excessive rate of smoking compared to the general population. Nicotine increases acoustic prepulse inhibition (PPI) in animals as well as healthy humans, suggesting that smoking may provide a way of restoring deficient sensorimotor gating in schizophrenia. No previous study has examined the neural mechanisms of the effect of nicotine on PPI in humans. OBJECTIVES: To investigate whether nicotine enhances tactile PPI in healthy subjects and patients with schizophrenia employing a double-blind, placebo-controlled, cross-over design and, if so, what are the neural correlates of nicotine-induced modulation of PPI. MATERIALS AND METHODS: In experiment 1, 12 healthy smokers, 12 healthy non-smokers and nine smoking schizophrenia patients underwent testing for tactile PPI on two occasions, 14 days apart, once after receiving (subcutaneously) 12 microg/kg body weight of nicotine and once after receiving saline (placebo). In experiment 2, six healthy subjects and five schizophrenia patients of the original sample (all male smokers) underwent functional magnetic resonance imaging (fMRI) under the same drug conditions and the same tactile PPI paradigm as in experiment 1. RESULTS: Nicotine enhanced PPI in both groups. A comparison of patterns of brain activation on nicotine vs placebo conditions showed increased activation of limbic regions and striatum in both groups after nicotine administration. Subsequent correlational analyses demonstrated that the PPI-enhancing effect of nicotine was related to increased hippocampal activity in both groups. CONCLUSIONS: Nicotine enhances tactile PPI in both healthy and schizophrenia groups. Our preliminary fMRI findings reveal that this effect is modulated by increased limbic activity.

Is susceptibility to perceptual migration and fusion modality-specific or multimodal?

A previous paper reported high susceptibility to spatial migration (allochiria) of tactile stimuli in about 25% of healthy individuals (High Error subjects). When synchronous stimuli touched the two hands, if the unattended stimulus was temporally modulated when the attended one was not (and was thus more salient than the latter), it "migrated" to and fused with or replaced the stimulus on the attended hand. When subjects rated similarity of the attended stimulus accompanied by a distractor to each stimulus alone, scaling distributions tested against a sampling model showed most High Error subjects experienced fused stimuli, others experienced replacement and Low Error subjects experienced neither. We argued that these migrations are equivalent to allochiria and that this underlies neglect and extinction. This study assessed whether the individual difference is modality-specific or not. In auditory and visual equivalents of the tactile rating experiment, the difference between High and Low Error subjects was replicated in audition, but no migration occurred in vision. However, when two words were briefly presented visually before a mask with cued report of one, letter migrations to equivalent locations did occur and the individual difference was reproduced. This constitutes the first report of individual differences in auditory fusion and visual letter migration. Migration occurred in egocentric coordinates but apparently preserved structural homology. Different migration rates between the modalities paralleled relative salience of the unattended to the attended stimulus. The multimodality of the individual difference suggests that its source is supramodal, in deficient binding of perceptual content to location.

Nicotine use in schizophrenia: the self medication hypotheses.

The behavioural and cognitive effects of nicotine in schizophrenia have received much interest in recent years. The rate of smoking in patients with schizophrenia is estimated to be two- to four-fold the rate seen in the general population. Furthermore such patients favour stronger cigarettes and may also extract more nicotine from their cigarettes than other smokers. The question has been raised whether the widespread smoking behaviour seen in this patient group is in fact a manifestation of a common underlying physiology, and that these patients smoke in an attempt to self-medicate. We present an overview of the explanations for elevated rates of smoking in schizophrenia, with particular emphasis on the theories relating this behaviour to sensory gating and cognitive deficits in this disorder that have been viewed as major support for the self-medication hypotheses.

Migration and fusion of tactile sensation--premorbid susceptibility to allochiria, neglect and extinction?

Migration of tactile sensation was found to occur very frequently in about 25% of normal people (High Error subjects) and very infrequently in others. When synchronous stimuli touched the two hands, if the unattended stimulus was modulated when the attended one was not (and was thus more salient) it "migrated" to the attended hand and fused with or replaced the attended stimulus. However, latencies reflecting congruence and incongruence of simultaneous stimuli showed that their identities on each hand had been (nonconsciously) registered veridically. Subsequent experiments, involving Focused and Divided Attention without speed pressure showed that mislocation errors in these subjects (i) were not due to confusion about location of otherwise perceptually distinct stimuli, (ii) nor to speed demand, (iii) nor to relative salience per se, (iv) were immune to attentional manipulation and practice in most subjects, (v) required a stimulus on the attended hand, and (vi) reflected a changed experience. Finally the same subjects rated similarity of the attended stimulus when accompanied by a distractor to each stimulus alone. Scaling distributions tested against a sampling model showed that most High Error subjects experienced a fusion of the stimuli, some experienced a replacement, and Low Error subjects experienced neither. The individual difference appears to be in attentional separability and spatial binding of tactile stimuli. Mislocation to the focus of spatial attention is common in healthy people, especially when binding is prevented. The present phenomenon appears equivalent to allochiria, but also accounts for phenomena in neglect and extinction, and suggests a premorbid susceptibility to spatial migration and integration that can be exaggerated by brain damage.