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Varma MM, Zeng S, Singh L, Holmes EA, Huang J, Chiu MH, Hu X. A systematic review and meta-analysis of experimental methods for modulating intrusive memories following lab-analogue trauma exposure in non-clinical populations. Nat Hum Behav 2024:10.1038/s41562-024-01956-y. [PMID: 39169230 DOI: 10.1038/s41562-024-01956-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 07/15/2024] [Indexed: 08/23/2024]
Abstract
Experiencing trauma leads to intrusive memories (IMs), a hallmark symptom of post-traumatic stress disorder (PTSD), which also occurs transdiagnostically. Understanding why IMs increase or decrease is pivotal in developing interventions to support mental health. In this preregistered meta-analysis (PROSPERO: CRD42021224835), we included 134 articles (131 techniques, 606 effect sizes and 12,074 non-clinical participants) to investigate how experimental techniques alter IM frequency, intrusion-related distress and symptoms arising from lab-analogue trauma exposure. Eligible articles were identified by searching eight databases until 12 December 2023. To test potential publication biases, we employed methods including Egger's test and three-parameter selection models. We employed three-level multilevel modelling and meta-regressions to examine whether and how experimental techniques would modulate IM frequency and associated outcomes. Results showed that techniques (behavioural, pharmacological, neuromodulation) significantly reduced intrusion frequency (g = 0.16, 95% confidence interval [0.09, 0.23]). Notably, techniques aimed to reduce IMs also ameliorated intrusion-related distress and symptoms, while techniques that increased IMs exacerbated these related outcomes, thus highlighting IM's centrality in PTSD-like symptoms. Techniques tapping into mental imagery processing (for example, trauma reminder followed by playing Tetris) reduced intrusions when administered immediately after, or at a delayed time after trauma. Although our meta-analysis is limited to symptoms induced by lab-analogue trauma exposure, some lab-based results have now generalized to real-world trauma and IMs, highlighting the promising utility of lab-analogue trauma paradigms for intervention development.
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Affiliation(s)
- Mohith M Varma
- Department of Management, Marketing, and Information Systems, Hong Kong Baptist University, Hong Kong SAR, China
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China
| | - Shengzi Zeng
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China
- The State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Laura Singh
- Department of Psychology, Uppsala University, Uppsala, Sweden
- Swedish Collegium for Advanced Study, Uppsala, Sweden
| | - Emily A Holmes
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Jingyun Huang
- School of Computer Science and Engineering, Sun Yat-sen University, Guangzhou, China
| | - Man Hey Chiu
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China
| | - Xiaoqing Hu
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China.
- The State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China.
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, China.
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Varma MM, Hu X. Prosocial behaviour reduces unwanted intrusions of experimental traumatic memories. Behav Res Ther 2021; 148:103998. [PMID: 34864480 DOI: 10.1016/j.brat.2021.103998] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 10/07/2021] [Accepted: 11/11/2021] [Indexed: 11/25/2022]
Abstract
Following trauma exposure, people often experience involuntary intrusions of traumatic memories, i.e., flashbacks. How to reduce such unwanted intrusions attracts attention from basic and translational memory research, with a goal to safeguard mental well-being and promote resilience. Here, based on prosocial behaviour's well-documented psychological benefits, we hypothesized that post-trauma prosocial behaviour would causally reduce trauma-related symptoms, including involuntary intrusions. To test this novel hypothesis, we conducted two pre-registered lab studies (N = 180) using trauma films to induce lab-analogue trauma exposure. Following trauma exposure, participants were randomly assigned to prosocial or non-prosocial conditions. Specifically, in the prosocial condition, participants donated money to their preferred charities. In the non-prosocial conditions, participants completed either a neutral, number judgement task (Experiment 1) or a proself task (Experiment 2). Participants completed a 1-week intrusion diary and Impact of Event Scale-Revised (IES-R), to assess frequencies of traumatic intrusions and post-trauma stress disorder symptoms, respectively. Results showed that compared to non-prosocial behaviour, prosocial engagement (i.e. performing charitable donations) reduced involuntary traumatic intrusions in both lab settings and in their daily life as evidenced by 1-week intrusion diaries. While exploratory mediation analyses suggested that intrusion reduction was partly driven by enhanced positive affect afforded by prosocial behaviour, future studies are required to illuminate the underlying mechanisms. To the extent that post-trauma prosociality alleviated trauma-related symptoms, future research is warranted to investigate how various forms of prosocial behaviour in naturalistic setting could promote resilience following trauma exposure.
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Affiliation(s)
- Mohith M Varma
- Department of Psychology, The University of Hong Kong, Hong Kong, China
| | - Xiaoqing Hu
- Department of Psychology, The University of Hong Kong, Hong Kong, China; The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China; HKU-Shenzhen Institute of Research and Innovation, Shenzhen, China.
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Moeck EK, Thomas NA, Takarangi MKT. Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes. Perception 2021; 50:27-38. [PMID: 33446070 DOI: 10.1177/0301006620982210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect-termed a right hemisphere memory bias-also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.
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Affiliation(s)
- Ella K Moeck
- College of Education, Psychology, and Social Work, Flinders University, Australia.,Turner Institute for Brain and Mental Health, Monash University, Australia
| | - Nicole A Thomas
- College of Education, Psychology, and Social Work, Flinders University, Australia; Turner Institute for Brain and Mental Health, Monash University, Australia
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Lau-Zhu A, Henson RN, Holmes EA. Intrusive memories and voluntary memory of a trauma film: Differential effects of a cognitive interference task after encoding. J Exp Psychol Gen 2019; 148:2154-2180. [PMID: 31021150 PMCID: PMC7116494 DOI: 10.1037/xge0000598] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Methods to reduce intrusive memories (e.g., of traumatic events) should ideally spare voluntary memory for the same event (e.g., to report on the event in court). Single-trace memory accounts assume that interfering with a trace should impact both its involuntary and voluntary expressions, whereas separate-trace accounts assume these two can dissociate, allowing for selective interference. This possibility was investigated in 3 experiments. Nonclinical participants viewed a trauma film followed by an interference task (Tetris game-play after reminder cues). Next, memory for the film was assessed with various measures. The interference task reduced the number of intrusive memories (diary-based, Experiments 1 and 2), but spared performance on well-matched measures of voluntary retrieval-free recall (Experiment 1) and recognition (Experiments 1 and 2)-challenging single-trace accounts. The interference task did not affect other measures of involuntary retrieval-perceptual priming (Experiment 1) or attentional bias (Experiment 2). However, the interference task did reduce the number of intrusive memories in a laboratory-based vigilance-intrusion task (Experiments 2 and 3), irrespective of concurrent working memory load during intrusion retrieval (Experiment 3). Collectively, results reveal a robust dissociation between intrusive and voluntary memories, having ruled out key methodological differences between how these two memory expressions are assessed, namely cue overlap (Experiment 1), attentional capture (Experiment 2), and retrieval load (Experiment 3). We argue that the inability of these retrieval factors to explain the selective interference is more compatible with separate-trace than single-trace accounts. Further theoretical developments are needed to account for this clinically important distinction between intrusive memories and their voluntary counterpart. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Affiliation(s)
- Alex Lau-Zhu
- Medical Research Council Cognition and Brain Sciences Unit
| | | | - Emily A Holmes
- Medical Research Council Cognition and Brain Sciences Unit
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Kuiling JME, Klaassen F, Hagenaars MA. The role of tonic immobility and control in the development of intrusive memories after experimental trauma. Memory 2019; 27:772-779. [PMID: 30747581 DOI: 10.1080/09658211.2018.1564331] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Tonic immobility (TI; state of motor inhibition during threat) has been implicated in the onset of intrusive trauma memories, while controllability was associated with reduced anxiety. The present study investigated the interaction between TI and control in the development of intrusive memories of an analogue trauma. Sixty-four participants watched negative pictures while being allowed to close their eyes (InControl) or not (NoControl). They completed measures for spontaneous TI afterwards and recorded intrusive memories of the pictures in a diary in the subsequent week. Bayesian analyses were used to test informative hypotheses. Spontaneous TI during picture viewing was positively associated with increased intrusion frequency. Intrusion frequency did not differ for InControl versus NoControl. Moderation (control x TI) and non-moderation (main effect of TI only) were both adequate models, with no preference. Our results confirm the importance of TI in PTSD development. Implications of the findings regarding control merit more research.
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Affiliation(s)
- J M E Kuiling
- a Department of Clinical Psychology , Radboud University Nijmegen and IrisZorg, Institute for Addiction Care , Arnhem , The Netherlands
| | - F Klaassen
- b Department of Methodology and Statistics , Utrecht University , Utrecht , The Netherlands
| | - M A Hagenaars
- c Department of Clinical Psychology , Utrecht University , Utrecht , The Netherlands
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Oulton JM, Strange D, Nixon RDV, Takarangi MKT. Imagining trauma: Memory amplification and the role of elaborative cognitions. J Behav Ther Exp Psychiatry 2018; 60:78-86. [PMID: 29753170 DOI: 10.1016/j.jbtep.2018.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 04/24/2018] [Accepted: 04/30/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND OBJECTIVES Trauma victims, such as war veterans, often remember additional traumatic events over time: the "memory amplification effect". This effect is associated with the re-experiencing symptoms of post-traumatic stress disorder (PTSD), including frequent and intrusive images of the trauma. One explanation for memory amplification is that people gradually incorporate new, imagined information about the trauma with what they actually experienced, leading to an amplified memory for what actually happened. We investigated this proposal here. METHODS Participants viewed highly negative and graphic photographs and recorded their intrusions. Critically, we instructed some participants to elaborate on their intrusions-that is, we asked them to imagine details about the trauma beyond what they actually witnessed. We assessed memory for the traumatic photos twice, 24-h apart. RESULTS The elaboration condition experienced fewer intrusions about the photos compared to the control condition. Furthermore, the elaboration condition were less susceptible to memory amplification compared to controls. LIMITATIONS The use of negative photos allowed experimental control, however does not permit generalization of our findings to real-world traumatic experiences. CONCLUSIONS Our findings suggest that effortful imagination of new trauma-related details leads to a reduction in intrusions and an increased tendency to not endorse trauma exposure over time. One explanation for this finding is that elaboration enhanced conceptual processing of the trauma analogue, therefore reducing intrusions. Critically, this reduction in intrusions affected participants' tendency to endorse trauma exposure, which is consistent with the reality-monitoring explanation for memory amplification.
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Affiliation(s)
| | - Deryn Strange
- Department of Psychology, John Jay College of Criminal Justice, USA.
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Sherrill AM, Kurby CA, Lilly MM, Magliano JP. The effects of state anxiety on analogue peritraumatic encoding and event memory: introducing the stressful event segmentation paradigm. Memory 2018; 27:124-136. [PMID: 29963967 DOI: 10.1080/09658211.2018.1492619] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Cognitive theories of PTSD argue that poor recall of trauma memories results from a stress-induced shift toward perceptual processing during encoding. The present study assessed the extent to which self-reported state anxiety affects event segmentation and its subsequent impact on memory performance (recall and recognition). Event segmentation is the cognitive process of condensing continuous streams of spatiotemporal information into discrete elements. In this study, undergraduates without PTSD used a computer programme to segment a stressful film and a non-stressful film and then they completed memory tasks for each film. For the stressful film, low memory performance was associated with high segmentation performance. A meditational analysis revealed high segmentation performance mediated a negative relationship between state anxiety and memory performance. Additionally, ad-hoc analyses suggest perceptual processing primarily drives segmentation of the stressful film and conceptual processing primarily drives segmentation of the non-stressful film.
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Affiliation(s)
- Andrew M Sherrill
- a Department of Psychiatry and Behavioral Sciences , Emory University School of Medicine , Atlanta , GA , USA
| | - Christopher A Kurby
- b Department of Psychology , Grand Valley State University , Allendale , MI , USA
| | - Michelle M Lilly
- c Department of Psychology , Northern Illinois University , DeKalb , IL , USA
| | - Joseph P Magliano
- c Department of Psychology , Northern Illinois University , DeKalb , IL , USA
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Marks EH, Franklin AR, Zoellner LA. Can't get it out of my mind: A systematic review of predictors of intrusive memories of distressing events. Psychol Bull 2018; 144:584-640. [PMID: 29553763 PMCID: PMC5938103 DOI: 10.1037/bul0000132] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Intrusive memories, when persistent and distressing, are theorized to underlie a range of transdiagnostic psychological symptoms and associated impairment. However, little is known about factors predicting the development and persistence of intrusive memories. The aim of this systematic review is to evaluate the literature on pre-event, event-based, and post-event predictors of intrusive memories. A systematic review was conducted, searching for studies that examined intrusive, event-based memories. One hundred and six articles were identified from PsycInfo, PubMed, and Medline databases. Experimental and prospective studies with clinical (N = 14) and nonclinical (N = 92) samples were critically reviewed, provided the inclusion of an analogue stressor with nonclinical samples, and that intrusive memories frequency and/or distress were assessed as primary dependent variables. Pre-existing psychopathology and pre-event appraisal style appear to predict intrusive memories (small to medium effects), whereas trait dissociation did not predict intrusive memories. Of studies examining event-based predictors, higher data-driven processing appears to predict intrusive memories with generally large effects. Post-event negative appraisals consistently predicted intrusive memories (medium to large effects), and preliminary evidence suggests higher post-event conceptual processing predicting fewer intrusive memories. This review synthesizes findings regarding a broad range of pre-event, event-based, and post-event factors that may influence the development of intrusive memories. Methodological issues of current paradigms and the lack of emphasis on memory retrieval processes limit our understanding of what predicts intrusive memory persistence. These limitations are particularly important given that individuals typically seek treatment for distressing intrusive memories once a memory has been fully consolidated, where retrieval processes are of utmost importance. (PsycINFO Database Record
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Involuntary autobiographical memories are relatively more often reported during high cognitive load tasks. Acta Psychol (Amst) 2018; 182:119-128. [PMID: 29169060 DOI: 10.1016/j.actpsy.2017.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 11/03/2017] [Accepted: 11/14/2017] [Indexed: 11/24/2022] Open
Abstract
Recent studies on involuntary autobiographical memories (IAMs) in daily life have shown that they are most frequently reported during daily routines (e.g. while ironing). Such studies have suggested that reporting IAMs may be influenced by the level of the ongoing task demands and availability of cognitive resources. In two studies, we investigated the effects of cognitive load on reporting IAMs. To examine the presumed cognitive load dependency of IAMs, we utilised an often-employed experimental paradigm (Schlagman & Kvavilashvili, 2008) to elicit IAMs under conditions that differed in cognitive load. When performing a vigilance task, participants had to interrupt the task each time they experienced any spontaneous mental contents and write them down. We manipulated the level of cognitive load by either instructing (cognitive load group) or not instructing (control group) participants to perform an additional demanding task. We compared the groups on the number of IAMs and other mental contents (non-IAM contents) recorded, as well as on the frequency of IAMs that was calculated as a proportion of IAMs in all mental contents reported by the participant. We expected that if reporting IAMs depends on the level of cognitive demands, then we should observe lower frequency of IAMs in the cognitive load group compared to the control group. Consistently across studies, we observed a lower number of IAMs and non-IAM contents in the cognitive load group. However, IAMs unexpectedly constituted a higher percentage of all mental contents when participants were cognitively loaded. Further implications of the cognitive load effects for IAMs research and experimental methodology are discussed.
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Pearson DG, Krans J. Editorial: Mental Imagery in Clinical Disorders. Front Psychiatry 2017; 8:49. [PMID: 28396642 PMCID: PMC5366310 DOI: 10.3389/fpsyt.2017.00049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 03/13/2017] [Indexed: 11/29/2022] Open
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Krans J, Pearson DG, Maier B, Moulds ML. Contextual representations of negative images modulate intrusion frequency in an intrusion provocation paradigm. J Behav Ther Exp Psychiatry 2016; 53:52-8. [PMID: 26424087 DOI: 10.1016/j.jbtep.2015.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/19/2015] [Accepted: 09/09/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVES To understand how memories of negative events become highly accessible in the context of trauma, we tested the hypothesis that contextual information modulates how easily intrusions can be provoked by perceptual stimuli.. METHODS Healthy participants viewed pictures depicting trauma scenes either with or without accompanying moderate (i.e. survival, recovery) or severe (i.e. fatality, permanent injury) outcome information. All participants viewed the same depictions of trauma scenes. Involuntary memories for the pictures were assessed using self-report diaries and an adapted version of the Impact of Event Scales (IES). A blurred picture perceptual priming paradigm was adapted to be used as an intrusion provocation task. RESULTS The severe outcome group experienced a significantly higher frequency of intrusions on the intrusion provocation task in comparison to both moderate outcome and control (no-context) conditions. The severe outcome condition did not increase intrusions on the self-report diaries or the adapted IES. There was no effect of condition on ratings for the emotionality, self-relevance, valence, or seriousness of the trauma scenes. LIMITATIONS The analogue method should not be generalized directly to incidences of real-life trauma. It was unclear why differences in intrusion frequency were found in the provocation task only. The relative amount of individual conceptual and data-driven processing adopted by the participants was not assessed. CONCLUSIONS Manipulating contextual information that determines the meaning of sensory-perceptual features for a trauma scene can modulate subsequent intrusion frequency in response to visually similar cues.
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Affiliation(s)
- J Krans
- School of Psychology, University of New South Wales, Sydney, Australia; Clinical Psychology, University of Leuven, Leuven, Belgium
| | - D G Pearson
- Department of Psychology, Anglia Ruskin University, Cambridge, UK.
| | - B Maier
- School of Psychology, University of New South Wales, Sydney, Australia
| | - M L Moulds
- School of Psychology, University of New South Wales, Sydney, Australia
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Oulton JM, Takarangi MKT, Strange D. Memory amplification for trauma: Investigating the role of analogue PTSD symptoms in the laboratory. J Anxiety Disord 2016; 42:60-70. [PMID: 27328014 DOI: 10.1016/j.janxdis.2016.06.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/31/2016] [Accepted: 06/02/2016] [Indexed: 10/21/2022]
Abstract
Victims of trauma often remember their experience as being more traumatic later, compared to immediately after, the event took place. This finding-the "memory amplification effect"-is associated with increased re-experiencing symptoms. However, the effect has been found almost exclusively in field-based studies. We examined whether the effect could be replicated in the laboratory. In two studies, we exposed participants to negative photographs and assessed their memory for the photographs and analogue PTSD symptoms on two occasions. In Study 1, analogue symptoms at follow-up were positively associated with remembering more negative photos over time. In Study 2, we focused on "memory amplifiers": people whose memory of the photos amplified over time. Consistent with field research, analogue re-experiencing symptoms were associated with memory amplification. Overall, our findings confirm that analogue PTSD symptoms are also associated with an amplified memory for a trauma analogue.
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Segovia DA, Strange D, Takarangi MKT. Encoding disorganized memories for an analogue trauma does not increase memory distortion or analogue symptoms of PTSD. J Behav Ther Exp Psychiatry 2016; 50:127-34. [PMID: 26189192 DOI: 10.1016/j.jbtep.2015.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 06/26/2015] [Accepted: 07/04/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND OBJECTIVES Empirical studies with objective measures and control conditions have failed to demonstrate disorganization; yet people tend to self-report disorganization in their trauma narratives, which may have other effects. Thus, we investigated whether a disorganized trauma memory produces more analogue PTSD symptoms and memory distortion, compared to an organized memory. METHODS Participants watched a traumatic film with missing scenes. Some saw the scenes in their correct temporal sequence; others saw a random sequence; thus for some participants we implanted a disorganized memory. We also told some participants to focus on the meaning of the event (conceptual), some on the sensory details (data-driven), and some received no instruction (control). Participants recorded their intrusions for a week. Then, they reported analogue symptoms and we tested their memory for the film and their confidence in what they remembered. RESULTS Analogue symptoms and number of reported intrusions did not differ across conditions, nor did the degree of memory distortion or confidence in those memories. However, participants who self-reported feeling more memory disorganization reported more avoidance symptoms and more memory distortion. LIMITATIONS We did not measure memory for real trauma, nor did we assess for a history of PTSD. Our results may also be restricted to temporal disorganization. CONCLUSIONS Although objective assessments of disorganization do not appear important, people's feelings regarding the disorganization of their memories not only affect their assessment of the severity of their PTSD symptoms, but also the kinds of memory errors they make.
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Clark IA, Mackay CE. Mental Imagery and Post-Traumatic Stress Disorder: A Neuroimaging and Experimental Psychopathology Approach to Intrusive Memories of Trauma. Front Psychiatry 2015; 6:104. [PMID: 26257660 PMCID: PMC4510312 DOI: 10.3389/fpsyt.2015.00104] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 07/03/2015] [Indexed: 01/11/2023] Open
Abstract
This hypothesis and theory paper presents a pragmatic framework to help bridge the clinical presentation and neuroscience of intrusive memories following psychological trauma. Intrusive memories are a hallmark symptom of post-traumatic stress disorder (PTSD). However, key questions, including those involving etiology, remain. In particular, we know little about the brain mechanisms involved in why only some moments of the trauma return as intrusive memories while others do not. We first present an overview of the patient experience of intrusive memories and the neuroimaging studies that have investigated intrusive memories in PTSD patients. Next, one mechanism of how to model intrusive memories in the laboratory, the trauma film paradigm, is examined. In particular, we focus on studies combining the trauma film paradigm with neuroimaging. Stemming from the clinical presentation and our current understanding of the processes involved in intrusive memories, we propose a framework in which an intrusive memory comprises five component parts; autobiographical (trauma) memory, involuntary recall, negative emotions, attention hijacking, and mental imagery. Each component part is considered in turn, both behaviorally and from a brain imaging perspective. A mapping of these five components onto our understanding of the brain is described. Unanswered questions that exist in our understanding of intrusive memories are considered using the proposed framework. Overall, we suggest that mental imagery is key to bridging the experience, memory, and intrusive recollection of the traumatic event. Further, we suggest that by considering the brain mechanisms involved in the component parts of an intrusive memory, in particular mental imagery, we may be able to aid the development of a firmer bridge between patients' experiences of intrusive memories and the clinical neuroscience behind them.
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Affiliation(s)
- Ian A. Clark
- Department of Psychiatry, University of Oxford, Oxford, UK
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Hagenaars MA, Mesbah R, Cremers H. Mental Imagery Affects Subsequent Automatic Defense Responses. Front Psychiatry 2015; 6:73. [PMID: 26089801 PMCID: PMC4453270 DOI: 10.3389/fpsyt.2015.00073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/29/2015] [Indexed: 11/13/2022] Open
Abstract
Automatic defense responses promote survival and appropriate action under threat. They have also been associated with the development of threat-related psychiatric syndromes. Targeting such automatic responses during threat may be useful in populations with frequent threat exposure. Here, two experiments explored whether mental imagery as a pre-trauma manipulation could influence fear bradycardia (a core characteristic of freezing) during subsequent analog trauma (affective picture viewing). Image-based interventions have proven successful in the treatment of threat-related disorders and are easily applicable. In Experiment 1, 43 healthy participants were randomly assigned to an imagery script condition. Participants executed a passive viewing task with blocks of neutral, pleasant, and unpleasant pictures after listening to an auditory script that was either related (with a positive or a negative outcome) or unrelated to the unpleasant pictures from the passive viewing task. Heart rate was assessed during script listening and during passive viewing. Imagining negative related scripts resulted in greater bradycardia (neutral-unpleasant contrast) than imagining positive scripts, especially unrelated. This effect was replicated in Experiment 2 (n = 51), again in the neutral-unpleasant contrast. An extra no-script condition showed that bradycardia was not induced by the negative-related script, but rather that a positive script attenuated bradycardia. These preliminary results might indicate reduced vigilance after unrelated positive events. Future research should replicate these findings using a larger sample. Either way, the findings show that highly automatic defense behavior can be influenced by relatively simple mental imagery manipulations.
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Affiliation(s)
- Muriel A Hagenaars
- Department of Clinical Psychology, Behavioural Science Institute, Radboud University Nijmegen , Nijmegen , Netherlands ; Department of Clinical Psychology, Leiden University , Leiden , Netherlands ; Biological Science Division, Department of Psychiatry, University of Chicago , Chicago, IL , USA
| | - Rahele Mesbah
- Department of Clinical Psychology, Leiden University , Leiden , Netherlands ; Department of Depression, PsyQ Rijnmond , Rotterdam , Netherlands
| | - Henk Cremers
- Department of Clinical Psychology, Leiden University , Leiden , Netherlands ; Biological Science Division, Department of Psychiatry, University of Chicago , Chicago, IL , USA
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Pearson DG. Are C-reps contextual representations? A reply to Brewin and Burgess. J Behav Ther Exp Psychiatry 2014; 45:220-2. [PMID: 24059963 DOI: 10.1016/j.jbtep.2013.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 10/26/2022]
Abstract
Brewin and Burgess (2013) argue that our recent papers investigating the role of contextual representations in intrusive memories do not pose a challenge to dual-representation theory as originally claimed (Pearson, 2012; Pearson, Ross, & Webster, 2012). Here I point out that their alternative explanation for our results can be rejected using data already published in both papers. I also argue that their definition of what constitutes a contextual representation renders their revised dual-representation theory incompatible with experimental results that have previously been argued in the literature to support it. Valuable though their contribution is, it does not impact on our main conclusion that abstract contextual representations serve to increase intrusive memories for traumatic material.
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Affiliation(s)
- David G Pearson
- School of Psychology, University of Aberdeen, William Guild Building, Aberdeen AB24 3FX, Scotland, UK.
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Price MC, Pearson DG. Toward a visuospatial developmental account of sequence-space synesthesia. Front Hum Neurosci 2013; 7:689. [PMID: 24187538 PMCID: PMC3807711 DOI: 10.3389/fnhum.2013.00689] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/30/2013] [Indexed: 12/03/2022] Open
Abstract
Sequence-space synesthetes experience some sequences (e.g., numbers, calendar units) as arranged in spatial forms, i.e., spatial patterns in their mind's eye or even outside their body. Various explanations have been offered for this phenomenon. Here we argue that these spatial forms are continuous with varieties of non-synesthetic visuospatial imagery and share their central characteristics. This includes their dynamic and elaborative nature, their involuntary feel, and consistency over time. Drawing from literatures on mental imagery and working memory, we suggest how the initial acquisition and subsequent elaboration of spatial forms could be accounted for in terms of the known developmental trajectory of visuospatial representations. This extends from the formation of image-based representations of verbal material in childhood to the later maturation of dynamic control of imagery. Individual differences in the development of visuospatial style also account for variation in the character of spatial forms, e.g., in terms of distinctions such as visual versus spatial imagery, or ego-centric versus object-based transformations.
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Affiliation(s)
- Mark C Price
- Psychology Faculty, University of Bergen Bergen, Norway
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