Imagery rescripting of emotional memories:A search for underlying mechanisms

Imagery Rescripting (IR) is a promising transdiagnostic psychotherapeutic technique that focuses on the modification of dysfunctional emotional memories. IR has proven to be an effective treatment in a variety of disorders ranging from anxiety and trauma-related disorders to depression and personality disorders. Despite its widespread use, research on the underlying working mechanisms of IR is still in its infancy. Improving our understanding of how and why IR leads to clinically significant change may ultimately enhance treatment effectiveness. The present thesis therefore aimed to investigate the working mechanisms of IR. For this purpose, we systematically studied the effects of IR versus established exposure-based treatments on artificially induced and clinically persistent emotional memories by combining experimental psychopathology with more applied research methodology in a series of studies. Both laboratory and treatment studies seem to support the hypothesis that IR taps into different processes when compared to exposure-based treatments, which may have critical implications for the treatment of emotional memories. Traditional exposure-based therapies induce new inhibitory memories, thereby leaving the original distressing memory unchanged and vulnerable for retrieval. In contrast, IR may provide a means to directly change the original memory through UCS-devaluation, which might lead to more generalizable and sustainable treatment effects. Although the present findings do not yet allow for any definite conclusions concerning the memory processes underlying IR, they advocate that the technique constitutes a valuable alternative therapeutic approach in the treatment of aversive emotional memories

Efficacy of imagery rescripting and imaginal exposure for nightmares:A randomized wait-list controlled trial

Nightmares can be effectively treated with cognitive-behavioral therapies. Though it remains elusive which therapeutic elements are responsible for the beneficial effects on nightmare symptoms, imagery rescripting (IR) and imaginal exposure (IE) are commonly identified as active treatment components of nightmare therapies. With this randomized controlled trial, we compared IR and IE as individual treatments to a wait-list (WL) condition to determine whether these particular therapeutic elements ameliorate nightmare symptoms. For this purpose, 104 patients with a primary DSM-5 diagnosis of nightmare disorder were randomly assigned to three weekly individual sessions of either IR or IE, or WL. Results showed that compared to WL, both interventions effectively reduced nightmare frequency (ΔdIR-WL = 0.74; ΔdIE-WL = 0.70) and distress (ΔdIR-WL = 0.98; ΔdIE-WL = 1.35) in a sample that predominantly consisted of idiopathic nightmare sufferers. The effects of IR and IE were comparable to those observed for other psychological nightmare treatments. Initial effects at post-treatment were sustained at 3- and 6-months follow-up, indicating that IR and IE both seem to be efficacious treatment components of nightmare therapies. Additional research is needed to directly compare IR and IE among both idiographic and posttraumatic nightmare sufferers with respect to treatment expectancy, acceptability, and effectiveness

Representational similarity analysis offers a preview of the noradrenergic modulation of long-term fear memory at the time of encoding

Neuroimaging research on emotional memory has greatly advanced our understanding of the pathogenesis of anxiety disorders. While the behavioral expression of fear at the time of encoding does not predict whether an aversive experience will evolve into long-term fear memory, the application of multi-voxel pattern analysis (MVPA) for the analysis of BOLD-MRI data has recently provided a unique marker for memory formation. Here, we aimed to further investigate the utility of this marker by modulating the strength of fear memory with an α2-adrenoceptor antagonist (yohimbine HCl). Fifty-two healthy participants were randomly assigned to two conditions - either receiving 20 mg yohimbine or a placebo pill (double-blind) - prior to differential fear conditioning and MRI-scanning. We examined the strength of fear associations during acquisition and retention of fear (48 h later) by assessing the similarity of BOLD-MRI patterns and pupil dilation responses. Additionally, participants returned for a follow-up test outside the scanner (2-4 weeks), during which we assessed fear-potentiated startle responses. Replicating our previous findings, neural pattern similarity reflected the development of fear associations over time, and unlike average activation or pupil dilation, predicted the later expression of fear memory (pupil dilation 48 h later). While no effect of yohimbine was observed on markers of autonomic arousal, including salivary α-amylase (sAA), we obtained indirect evidence for the noradrenergic enhancement of fear memory consolidation: sAA levels showed a strong increase prior to fMRI scanning, irrespective of whether participants had received yohimbine, and this increase correlated with the subsequent expression of fear (48 h later). Remarkably, this noradrenergic enhancement of fear was associated with changes in neural response patterns at the time of learning. These findings provide further evidence that representational similarity analysis is a sensitive tool for studying (enhanced) memory formation

Effects of anisotropic dynamics on cosmic strings

The dynamics of cosmic strings is considered in anisotropic backgrounds. In particular, the behaviour of infinitely long straight cosmic strings and of cosmic string loops is determined. Small perturbations of a straight cosmic string are calculated. The relevance of these results is discussed with respect to the possible observational imprints of an anisotropic phase on the behaviour of a cosmic string network.Comment: 16 pages, 9 figures; matches version published in JCA