Neuromodulation of Visual Cortex Reduces the Intensity of Intrusive Memories.

Aversive events can be reexperienced as involuntary and spontaneous mental images of the event. Given that the vividness of retrieved mental images is coupled with elevated visual activation, we tested whether neuromodulation of the visual cortex would reduce the frequency and negative emotional intensity of intrusive memories. Intrusive memories of a viewed trauma film and their accompanied emotional intensity were recorded throughout 5 days. Functional connectivity, measured with resting-state functional magnetic resonance imaging prior to film viewing, was used as predictive marker for intrusions-related negative emotional intensity. Results indicated that an interaction between the visual network and emotion processing areas predicted intrusions' emotional intensity. To test the causal influence of early visual cortex activity on intrusions' emotional intensity, participants' memory of the film was reactivated by brief reminders 1 day following film viewing, followed by inhibitory 1 Hz repetitive transcranial magnetic stimulation (rTMS) over early visual cortex. Results showed that visual cortex inhibitory stimulation reduced the emotional intensity of later intrusions, while leaving intrusion frequency and explicit visual memory intact. Current findings suggest that early visual areas constitute a central node influencing the emotional intensity of intrusive memories for negative events. Potential neuroscience-driven intervention targets designed to downregulate the emotional intensity of intrusive memories are discussed.

Recurrent involuntary autobiographical memories: characteristics and links to mental health status.

Memories of events from one's personal past that come to mind unintentionally and effortlessly are termed involuntary autobiographical memories (IAMs). Recurrent IAMs are known as relevant to many disorders within clinical literature. However, less is known about their links with mental health status in the general population. In the current study, 2184 undergraduate students completed surveys assessing occurrence of any recurrent IAMs. Participants also wrote a description of their most frequently recurring IAM and rated it on phenomenological characteristics, such as frequency, valence, vividness, and centrality. Results showed that the majority of our sample experienced recurrent IAMs, replicating previous findings, but most of these memories were emotionally negative, unlike past work. Importantly, negative recurrent IAMs were associated with significantly more mental health concerns, including symptoms of depression, anxiety, and posttraumatic stress. We also found that frequency of IAM recurrence was predicted by the memory's age, level of completeness/detail, emotional intensity, and centrality to one's life story. Further, descriptions of positive recurrent IAMs contained significantly more episodic detail compared to negative or neutral ones, suggesting that emotional regulation may play a role in how recurrent IAMs are recounted. Recurrent IAMs, and their characteristics, serve as a window into mental health status.

Enhanced accessibility of ignored neutral and negative items in nonclinical dissociative individuals.

While clinical studies showed paradoxical memory phenomena, including the intrusion and amnesia of stressful experiences that are features of dissociation, the results of laboratory studies on dissociative individuals' forgetting of experimental stimuli through cognitive control varied. Some studies demonstrated ineffective inhibition, and others found that dissociative individuals could remember fewer trauma words in a divided-attention context. Dissociative individuals may utilize superior cognitive disengagement to forget the representations. This hypothesis was tested in nonclinical individuals with high, medium, and low dissociation proneness. In the study phase, the participants learned several lists of experimental words and kept updating working memory by remembering the last four items on a list (target) and ignoring those non-target items. A recognition test was then conducted. The high dissociation group performed better on updating working memory. However, the accessibility of the representations of neutral and negative non-target items was elevated. Dissociative individuals disengaged attention effectively from items they intended to ignore, and the representations of the ignored items were more accessible when cues were available.

Association between intrusive negative autobiographical memories and depression: A meta-analytic investigation.

The study investigated several associations between depression and intrusive negative autobiographical memories. A systematic literature search identified 23 eligible studies (N = 2,582), which provided 59 effect sizes. Separate meta-analyses indicated that depression was moderately, positively associated with intrusive memory frequency, memory distress, maladaptive memory appraisals, memory avoidance, and memory rumination. Intrusive memory vividness was not significantly associated with depression. There were insufficient data to examine the relationship between depression and memory vantage perspective. Between-study heterogeneity was high for intrusive memory frequency and memory avoidance, and the percentage of females in studies significantly moderated the relationship between these variables and depression. An additional exploratory meta-analysis (3 studies; N = 257) indicated that intrusive memories were experienced more frequently by those with posttraumatic stress disorder than those with depression. Overall, the findings suggest that intrusive memories warrant clinical attention as they may contribute to the maintenance of depressive symptomatology.

Computer Game Play Reduces Intrusive Memories of Experimental Trauma via Reconsolidation-Update Mechanisms.

Memory of a traumatic event becomes consolidated within hours. Intrusive memories can then flash back repeatedly into the mind's eye and cause distress. We investigated whether reconsolidation-the process during which memories become malleable when recalled-can be blocked using a cognitive task and whether such an approach can reduce these unbidden intrusions. We predicted that reconsolidation of a reactivated visual memory of experimental trauma could be disrupted by engaging in a visuospatial task that would compete for visual working memory resources. We showed that intrusive memories were virtually abolished by playing the computer game Tetris following a memory-reactivation task 24 hr after initial exposure to experimental trauma. Furthermore, both memory reactivation and playing Tetris were required to reduce subsequent intrusions (Experiment 2), consistent with reconsolidation-update mechanisms. A simple, noninvasive cognitive-task procedure administered after emotional memory has already consolidated (i.e., > 24 hours after exposure to experimental trauma) may prevent the recurrence of intrusive memories of those emotional events.

The effect of a visuospatial interference intervention on posttraumatic intrusions: a cross-over randomized controlled trial.

Background: Intrusive memories form a core symptom of Posttraumatic Stress Disorder (PTSD). Based on concepts of visuospatial interference and memory-updating accounts, technological innovations aim to attenuate such intrusions using visuospatial interventions.Objective: This study aims to test the effect of a visuospatial Tetris-based intervention versus a verbal condition (Wiki) and a never-targeted control (no intervention) on intrusion frequency.Method: A randomized crossover trial was conducted including N = 38 PTSD patients who had at least 3 distinct intrusive memories of trauma. After both 2 weeks (intervention 1) and 4 weeks (intervention 2), one of the three memories was randomly selected and either the visuospatial intervention (memory reminder of a traumatic memory + Tetris) or verbal condition (reading a Wikipedia article + answering questions) was performed on their first memory in randomized order. In the week 4 session, the patient conducted the other intervention condition on their second memory (crossover). The third memory was never targeted (no intervention). Daily occurrence of intrusions over 8 weeks was collected using a diary and analysed using mixed Poisson regression models.Results: Overall, there was no significant reduction in intrusion frequency from either intervention compared to each other, and to no intervention control (relative risk Tetris/Wiki: 0.947; p = .31; relative risk no intervention/Tetris: 1.060; p = .15; relative risk no intervention/Wiki: 1.004; p = .92).Conclusions: There was no effect of either intervention on intrusions when administered in a crossover design where participants received both interventions. Design shortcomings and consequences for future studies are discussed.

Visuospatial interventions, including the computer game Tetris, have been studied as a potential means to decrease intrusive memories, a core feature of Posttraumatic Stress Disorder.In this study, two interventions are tested in a crossover design with patients with intrusive memories after traumatic experiences.There was no effect of either the visuospatial intervention or the verbal condition in this design.

Identification of a narrow post-ovulatory window of vulnerability to distressing involuntary memories in healthy women.

Psychological disorders characterised by intrusive memories are more prevalent in women than men. The biological, social and cognitive processes underlying this gender-difference have yet to be fully elucidated. Some evidence suggests that (fluctuations in) ovarian hormone levels are responsible for altered sensitivity to emotional stimuli during certain phases in the menstrual-cycle and this may form the basis of a specific vulnerability to psychological disorders in women. The post-ovulatory (luteal) phase has been identified as a period of particular vulnerability to the development of post-traumatic stress disorder (PTSD). Using an experimental model of PTSD, we examine whether differences are detectable between discrete phases in the menstrual-cycle in the experience of intrusive memories. Women (18-35 years-old) in one of three tightly-defined periods within the menstrual cycle--mid-follicular (n=15), early-luteal (n=15) and late-luteal (n=11)--provided saliva samples for ovarian-hormone assay and watched a distressing film. Subsequent intrusive memories, assessed using a daily online-diary, occurred significantly more frequently in the early-luteal group compared to mid-follicular and late-luteal groups. Intrusion frequency was negatively correlated with the estradiol-to-progesterone ratio, but not estradiol or progesterone alone, suggesting that the interactive effect of low estradiol and high progesterone at encoding contributes to the observed effect. Our results support the need for further research in a clinical context with naturally-cycling women who experience a traumatic event, since assessment of days-since-last-menses and ovarian hormone levels may help to identify those at greatest risk of developing re-experiencing symptoms akin to those seen in psychological disorder such as depression and PTSD.

Effect of sleep manipulations on intrusive memories after exposure to an experimental analogue trauma: A meta-analytic review.

Sleep plays an important role in memory processing and is disrupted in individuals with post-traumatic stress disorder (PTSD). A growing body of research has experimentally investigated how sleep - or lack thereof - in the early aftermath of a traumatic experience contributes to intrusive memory formation. The aim of this meta-analytic review was to examine the effects of various experimental sleep manipulations (e.g., sleep deprivation, daytime naps) on intrusive memories following exposure to an experimentally induced analogue traumatic event. Eight eligible studies were systematically identified through PsycInfo and PubMed and provided sufficient data to contribute to a meta-analysis of the effects of sleep versus wakefulness on intrusive memory frequency. Sleep was found to reduce intrusive memory frequency when compared to wakefulness at a small but significant effect size (Hedge's g = 0.29). There was no evidence of publication bias and heterogeneity of effect sizes across studies was moderate. Results suggest that sleep plays a protective role in the aftermath of exposure to a traumatic event with implications for early post-trauma intervention efforts.

A Naturalistic Paradigm to Investigate Postencoding Neural Activation Patterns in Relation to Subsequent Voluntary and Intrusive Recall of Distressing Events.

BACKGROUND: While neuroimaging has provided insights into the formation of episodic memories in relation to voluntary memory recall, less is known about neural mechanisms that cause memories to occur involuntarily, for example, as intrusive memories of trauma. Here, we investigated brain activity shortly after viewing distressing events as a function of whether memories for those events later intruded involuntarily. The postencoding period is particularly important because it is a period when clinical interventions could be applied. METHODS: A total of 32 healthy volunteers underwent functional magnetic resonance imaging while viewing distressing film clips, interspersed with 5 minutes of awake (postencoding) rest. Voluntary memories of the films were assessed using free recall and verbal and visual recognition tests after a week, while intrusive (involuntary) memories were recorded in a diary throughout that week. RESULTS: When analyzing functional magnetic resonance imaging responses related to watching the films, we replicated findings that those "hotspots" (salient moments within the films) that would later become intrusive memories elicited higher activation in parts of the brain's salience network. Surprisingly, while the postencoding persistence of multivoxel correlation structures associated with entire film clips predicted subsequent voluntary recall, there was no evidence that they predicted subsequent intrusions. CONCLUSIONS: Results replicate findings regarding the formation of intrusive memories during encoding and extend findings regarding the consolidation of information in postencoding rest in relation to voluntary memory. While we provided a first step using a naturalistic paradigm, further research is needed to elucidate the role of postencoding neural processes in the development of intrusive memories.

Sleep spindle dynamics suggest over-consolidation in post-traumatic stress disorder.

Devastating and persisting traumatic memories are a central symptom of post-traumatic stress disorder (PTSD). Sleep problems are highly co-occurrent with PTSD and intertwined with its etiology. Notably, sleep hosts memory consolidation processes, supported by sleep spindles (11-16 Hz). Here we assess the hypothesis that intrusive memory symptoms in PTSD may arise from excessive memory consolidation, reflected in exaggerated spindling. We use a newly developed spindle detection method, entailing minimal assumptions regarding spindle phenotype, to assess spindle activity in PTSD patients and traumatized controls. Our results show increased spindle activity in PTSD, which positively correlates with daytime intrusive memory symptoms. Together, these findings provide a putative mechanism through which the profound sleep disturbance in PTSD may contribute to memory problems. Due to its uniform and unbiased approach, the new, minimal assumption spindle analysis seems a promising tool to detect aberrant spindling in psychiatric disorders.

Threat memory devaluation by a dual-task intervention: Testing return of fear and intrusive memory over 48 hours.

BACKGROUND AND OBJECTIVES: In dual-tasking, individuals recall a threat-related memory while performing a demanding dual-task. This is a fruitful approach to reduce the unpleasantness and vividness of aversive memories and to reduce conditioned fear responses. Crucially, it remains unclear whether dual-tasking can also reduce conditioned fear responses and intrusive memories over time. In this pre-registered two-day fear conditioning paradigm, we examined whether a dual-task intervention reduces return of fear and the frequency of intrusive memories of an aversive film over time. METHODS: On Day 1, 76 healthy participants underwent fear acquisition with aversive film clips. They were then randomly allocated to one of three conditions: dual-tasking, memory recall without a dual-task ('recall only'), or no task. Afterwards, they underwent an extinction phase and were asked to record intrusive film memories over 48 h. On Day 3, return of fear was assessed. RESULTS: On Day 1, fear acquisition and extinction were successful. On Day 3, spontaneous recovery and renewal were evident, but, overall, participants reported few intrusions. The dual-task and recall only groups reported reduced unpleasantness of threat memory compared to the no task group, but they did not show reduced (return of) fear responses or fewer intrusions. LIMITATIONS: Intrusion frequency was low in all three groups, which limits the detection of intervention effects. CONCLUSIONS: Even though dual-tasking and recall only devalued threat memory temporarily compared to no task, these interventions did not reduce (return of) fear responses and intrusions. Future studies could focus on improving the potency of imagery-based interventions.

Condensed internet-delivered prolonged exposure provided soon after trauma: A randomised pilot trial.

Exposure to trauma is common and may have detrimental psychological consequences. Brief exposure therapy provided early after trauma has shown encouraging results in promoting recovery. To scale up treatment availability, we developed a 3-week internet-delivered intervention comprised of four modules based on prolonged exposure (condensed internet-delivered prolonged exposure; CIPE) with therapist support. In this pilot study, we assessed the feasibility, acceptability, and preliminary efficacy of CIPE delivered within 2 months after the index event. Thirty-three participants were randomised to CIPE or a waiting list (WL). The frequency, vividness and distress of intrusive recollections or flashback memories of the traumatic event were assessed using an intrusive memory smartphone app. Symptoms of post-traumatic stress were assessed by the PTSD Symptom Checklist for DSM-5 (PCL-5). The most common index traumas in the sample were rape, interpersonal violence and life-threatening accidents. A majority of participants (82%) randomised to CIPE completed all modules, and the number of logins per participant to the Internet platform was high during the three-week intervention (M = 19.6, SD = 11.8). At post-treatment, the CIPE participants had a more favourable reduction than the WL group on the vividness and distress ratings, as well as on the PCL-5 sum score (bootstrapped d = 0.85; 95% CI [0.25-1.45]). Treatment effects were sustained at 6-months follow up and no severe adverse events associated with the intervention were found. CIPE seems to be a feasible and possibly efficacious early intervention after trauma. Large-scale trials are needed to assess its efficacy and long-term benefits.

The influence of ruminative processing mode on the trajectory of intrusive memories following a negative mood induction.

BACKGROUND AND OBJECTIVES: Rumination following an event, particularly in an abstract as opposed to concrete processing mode, is associated with increased intrusive memory frequency. However, the temporal trajectory of intrusive memories following abstract and concrete rumination remains unclear. We examined the association between processing mode and the frequency of intrusive memories over a 6-h time period following a negative mood induction. METHODS: One hundred and sixteen community participants watched a video sequence designed to induce negative mood. Participants were then randomised into condition (abstract, concrete or distraction) and completed a verbally mediated task designed to induce the respective processing mode. Participants then completed hourly ratings of rumination and intrusive memories about the video after leaving the laboratory. RESULTS: Negative mood and intrusive memories were reliably induced. There were no differences in the frequency of intrusive memories between the abstract and concrete conditions. In contrast, participants in the distraction condition reported significantly more sensory intrusive memories than either ruminative condition. Three classes were found among participants following the video (intrusion free, rapid remitters, slow remitters). Condition was not predictive of class membership. LIMITATIONS: It cannot be ruled out that the differences between rumination and distraction conditions were due to task differences. CONCLUSIONS: In contrast to previous findings, our results suggest that any form of rumination about an event (whether in an abstract or concrete mode) may temporarily result in fewer intrusive memories in comparison to distraction. Processing mode does not appear to predict particular trajectories of intrusions following a mood induction.

Improving imagery rescripting treatments: Comparing an active versus passive approach.

BACKGROUND AND OBJECTIVES: In imagery rescripting (ImRs), aversive mental images are modified to reduce symptoms in a variety of psychological disorders. However, uniform guidelines on how to optimally implement ImRs do currently not exist. It remains unclear whether therapists should stimulate patients to imagine themselves to actively intervene within the new image, or whether they may imagine helpers to change the situation. We aimed to compare these two variants of ImRs within an analogue experimental setting. METHODS: After having watched an aversive film, one-hundred participants were randomly assigned to active ImRs (ImRs-A), passive ImRs (ImRs-P), imagery rehearsal (IRE), or no-intervention control (NIC). Participants were either instructed to rescript the film by imagining themselves intervening in the new script (ImRs-A) or encouraged to imagine helpers to intervene in the imagined situation (ImRs-P). RESULTS: Both ImRs increased mastery and elicited less distress than IRE with ImRs-P being experienced as less distressing than ImRs-A. Only ImRs-A led to a stronger increase in positive affect than IRE, whereas groups did not differ with respect to negative affect and self-efficacy. Conditions did not differ regarding the number of film-related intrusive memories. LIMITATIONS: As a convenience sample was investigated, results cannot be generalized to clinical samples. CONCLUSION: Even though differences regarding symptomatic outcome could not be detected, ImRs-P was experienced as less distressing than ImRs-A. Results suggest that both ImRs lead to different processes during the intervention than mere exposure. Compared to IRE, ImRs increases mastery with ImRs-A and ImRs-P being equally effective.

The prevalence of intrusive memories in adult depression: A meta-analysis.

BACKGROUND: Intrusive memories have typically been associated with post-traumatic stress disorder (PTSD) but some studies have suggested they can also occur in depression-alone. OBJECTIVE: This meta-analysis aimed to estimate the prevalence of intrusive memories in adult depression and to explore methodological and other factors that may moderate this prevalence. METHOD: The databases PsycINFO, PsycARTICLES, MedLine, PubMed, CINAHL and Embase were searched for relevant articles, published up to and including July 2016. Studies measuring point prevalence of intrusive memories in adults aged 18 years or above with depression were included and assessed for quality. Meta-analysis was completed under a random effects model. RESULTS: Seven studies measuring point prevalence of intrusive memories in adult depression were included. The overall pooled prevalence estimate calculated was 76.0% (95% CI 59.4-89.4%), reducing to 66.0% (95% CI 51.0-79.5%) when restricted to intrusive memories experienced within the week prior to assessment. Heterogeneity was high. Between-groups analyses indicated that adults with depression are as likely to experience intrusive memories as adults with PTSD, and more likely to experience intrusive memories than healthy controls (risk ratio of 2.94, 95% CI 1.53-5.67). LIMITATIONS: The strength of conclusions is limited by the small number of studies included. Consideration of the relationship between depression, intrusive memories and trauma exposure is required. CONCLUSIONS: Intrusive memories are experienced by a large majority of adults with depression and may therefore be an important target for cognitive intervention. Larger scale measurement of clinical outcome is needed with identification of individual factors predicting treatment response.

Effects of imagery rescripting on consolidated memories of an aversive film.

BACKGROUND AND OBJECTIVES: Imagery rescripting (ImRs) is a promising intervention targeting emotional memory. Previous analogue studies have mainly investigated effects of ImRs during memory encoding and consolidation; experimental research on the effects and mechanisms of change in ImRs targeting consolidated memories is largely missing. The present study aimed to investigate effects of ImRs on consolidated memories using a multiple-day trauma film paradigm. METHODS: Eighty-eight participants were randomly assigned to either ImRs, imagery rehearsal (IRE), or no intervention control (NIC). In Session 1, participants watched an aversive film. In Session 2 (24 h after Session 1), the analogue trauma memory was reactivated and the intervention took place. Participants reported intrusive memories of the aversive film for one week and then returned to the laboratory for a follow-up (Session 3). RESULTS: Compared to IRE, ImRs was experienced as less distressing and elicited less negative emotions. In addition, ImRs accelerated the decline of intrusive memories when compared to NIC. However, ImRs, IRE, and NIC did not differ with respect to the total number of intrusive memories during the week following the intervention. LIMITATIONS: There was a floor effect of intrusive memories, which may have obscured a potential superiority of the active interventions over NIC. CONCLUSIONS: Adding to the current literature on ImRs as an intervention for emotional memories, the current study underscores that a multiple-day trauma film paradigm can be used to investigate the short-term efficacy and working mechanisms of ImRs, but also points toward useful modifications to the paradigm.

Intrusive memories of trauma: A target for research bridging cognitive science and its clinical application.

Intrusive memories of a traumatic event can be distressing and disruptive, and comprise a core clinical feature of post-traumatic stress disorder (PTSD). Intrusive memories involve mental imagery-based impressions that intrude into mind involuntarily, and are emotional. Here we consider how recent advances in cognitive science have fueled our understanding of the development and possible treatment of intrusive memories of trauma. We conducted a systematic literature search in PubMed, selecting articles published from 2008 to 2018 that used the terms "trauma" AND ("intrusive memories" OR "involuntary memories") in their abstract or title. First, we discuss studies that investigated internal (neural, hormonal, psychophysiological, and cognitive) processes that contribute to intrusive memory development. Second, we discuss studies that targeted these processes using behavioural/pharmacological interventions to reduce intrusive memories. Third, we consider possible clinical implications of this work and highlight some emerging research avenues for treatment and prevention, supplemented by new data to examine some unanswered questions. In conclusion, we raise the possibility that intrusive memories comprise an alternative, possibly more focused, target in translational research endeavours, rather than only targeting overall symptoms of disorders such as PTSD. If so, relatively simple approaches could help to address the need for easy-to-deliver, widely-scalable trauma interventions.

The effects of dual-tasks on intrusive memories following analogue trauma.

Patients with post-traumatic stress disorder frequently and involuntarily experience intrusions, which are strongly linked to the trauma hotspot. Voluntary memory characteristics (i.e., vividness and unpleasantness) of this hotspot can be reduced by performing a dual-task, such as making horizontal eye movements, which is frequently used in Eye Movement Desensitization and Reprocessing. We tested whether such dual-task interventions would also reduce involuntary memory (i.e., intrusions). Moreover, we examined if changes in hotspot vividness and unpleasantness predicted intrusion frequency. Additionally, we examined whether the effects were dependent on dual-task modality. We tested this in three experiments. Participants watched a trauma film and performed one of the interventions 10-min post-film (1) Recall + Eye movements, (2) Recall + Counting, or (3) No-Task Control. Before and after the intervention, participants rated the hotspot vividness and unpleasantness. They recorded intrusive memories about the film in a diary for a week. Unexpectedly, we found that hotspot vividness and unpleasantness ratings were not affected by the intervention. However, the prolonged (experiment 2), but not standard (experiment 1), dual-task interventions resulted in a lower number of intrusions, regardless of modality. However, this effect was not replicated in experiment 3. We discuss potential explanations and present suggestions for future research.

Multiple memory systems, multiple time points: how science can inform treatment to control the expression of unwanted emotional memories.

Memories that have strong emotions associated with them are particularly resilient to forgetting. This is not necessarily problematic, however some aspects of memory can be. In particular, the involuntary expression of those memories, e.g. intrusive memories after trauma, are core to certain psychological disorders. Since the beginning of this century, research using animal models shows that it is possible to change the underlying memory, for example by interfering with its consolidation or reconsolidation. While the idea of targeting maladaptive memories is promising for the treatment of stress and anxiety disorders, a direct application of the procedures used in non-human animals to humans in clinical settings is not straightforward. In translational research, more attention needs to be paid to specifying what aspect of memory (i) can be modified and (ii) should be modified. This requires a clear conceptualization of what aspect of memory is being targeted, and how different memory expressions may map onto clinical symptoms. Furthermore, memory processes are dynamic, so procedural details concerning timing are crucial when implementing a treatment and when assessing its effectiveness. To target emotional memory in its full complexity, including its malleability, science cannot rely on a single method, species or paradigm. Rather, a constructive dialogue is needed between multiple levels of research, all the way 'from mice to mental health'.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'.

Tetris and Word games lead to fewer intrusive memories when applied several days after analogue trauma.

Background: Intrusive trauma memories are a key symptom of posttraumatic stress disorder (PTSD), so disrupting their recurrence is highly important. Intrusion development was hindered by visuospatial interventions administered up to 24 hours after analogue trauma. It is unknown whether interventions can be applied later, and whether modality or working-memory load are crucial factors. Objectives: This study tested: (1) whether a visuospatial task would lead to fewer intrusions compared to a reactivation-only group when applied after memory reactivation four days after analogue trauma exposure (extended replication), (2) whether both tasks (i.e. one aimed to be visuospatial, one more verbal) would lead to fewer intrusions than the reactivation-only group (intervention effect), and (3) whether supposed task modality (visuospatial or verbal) is a critical component (modality effect). Method: Fifty-four participants were randomly assigned to reactivation+Tetris (visuospatial), reactivation+Word games (verbal), or reactivation-only (no task). They watched an aversive film (day 0) and recorded intrusive memories of the film in diary A. On day 4, memory was reactivated, after which participants played Tetris, Word games, or had no task for 10 minutes. They then kept a second diary (B). Informative hypotheses were evaluated using Bayes factors. Results: Reactivation+Tetris and reactivation+Word games resulted in relatively fewer intrusions from the last day of diary A to the first day of diary B than reactivation-only (objective 1 and 2). Thus, both tasks were effective even when applied days after analogue trauma. Reactivation-only was not effective. Reactivation+Word games appeared to result in fewer intrusions than reactivation+Tetris (objective 3; modality effect), but this evidence was weak. Explorative analyses showed that Word games were more difficult than Tetris. Conclusions: Applying a task four days after the trauma film (during memory reconsolidation) was effective. The modality versus working-memory load issue is inconclusive.

Planteamiento: Los recuerdos intrusivos de trauma son un síntoma clave del trastorno de estrés postraumático (TEPT), por lo que es muy importante interrumpir su recurrencia. Se obstaculizó el desarrollo de intrusiones mediante intervenciones visuoespaciales administradas hasta 24 horas después de un trauma analógico. Se desconoce si las intervenciones pueden ser aplicadas más adelante, y si la modalidad o la carga de la memoria de trabajo son factores cruciales. Objetivos: El estudio comprobaba: (1) si una tarea visuoespacial conduciría a menos intrusiones en comparación con un grupo de solo reactivación cuando se aplicaba después de la reactivación del recuerdo, 4 días después de la exposición al trauma analógico (replicación extendida); (2) si ambas tareas (una pretendía ser más visuoespacial y otra más verbal) darían lugar a menos intrusiones que el grupo de solo reactivación (efecto de la intervención), y 3) si la supuesta modalidad de la tarea (visuoespacial o verbal) es un componente fundamental (efecto de la modalidad). Método: Se asignaron aleatoriamente 54 participantes a reactivación + Tetris (visuoespacial), reactivación + juegos de palabras (verbal), o solo reactivación (sin tarea). Vieron una película aversiva (día 0) y registraron recuerdos intrusivos de la película en el diario A. El cuarto día, se reactivó el recuerdo, después de lo cual los participantes jugaron al Tetris, a juegos de palabras, o no hicieron ninguna tarea durante 10 minutos. Luego escribieron un segundo diario (B). Se evaluaron las hipótesis informativas con factores de Bayes. Resultados: Reactivación + Tetris y reactivación + juegos de palabras dieron como resultado relativamente menos intrusiones que sólo la reactivación (objetivo 1 y 2), desde el último día del diario A hasta el primer día del diario B. Por lo tanto, ambas tareas fueron eficaces incluso cuando se aplicaron días después del trauma analógico. La reactivación por separado no fue efectiva. Reactivación + juegos de palabras pareció resultar en menos intrusiones que reactivación + Tetris (objetivo 3, efecto de la modalidad), pero esta evidencia era débil. Los análisis exploratorios mostraron que los juegos de palabras eran más difíciles que el Tetris. Conclusiones: La aplicación de una tarea 4 días después de la película traumática (durante la reconsolidación de la memoria) fue efectiva. La modalidad versus el problema de la carga de memoria de trabajo no es concluyente.