Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Farewell flashbacks (Developing science-driven therapies after trauma: Neural mechanisms underlying the modification of intrusive emotional memories)

Teaser

Unfortunately, most people will experience a traumatic event (e.g., a serious car crash or mugging) during their lives. In a subset of individuals, psychological trauma will lead to the development of a mental disorder such as posttraumatic stress disorder (PTSD). One of the...

Summary

Unfortunately, most people will experience a traumatic event (e.g., a serious car crash or mugging) during their lives. In a subset of individuals, psychological trauma will lead to the development of a mental disorder such as posttraumatic stress disorder (PTSD). One of the hallmark symptoms of PTSD and acute stress disorder involves ‘recurrent, involuntary and intrusive memories of the traumatic event’. These intrusive memories (in their most extreme form referred to as ‘flashbacks’) are hypothesized to stem from maladaptive memory processes: the memory of the event is easily triggered, without conscious effort. This results in mental images ‘springing’ to one’s mind unbidden, often causing considerable distress. A line of experimental research spearheaded by Professor Emily Holmes (the project’s supervisor) suggests that the number of intrusive images that people experience after a stressful event can be reduced by a reminder cue plus distracting computer game play (e.g., Tetris) during or shortly after the event (Figure 1). The mechanisms underlying these so-called ‘competing tasks’ effects are not well understood. The overarching aim of the project was to investigate procedures to ameliorate intrusive memories of psychological trauma by bringing novel insights from basic neuroscience to the field of mental health. For this we used a multidisciplinary research approach combining state-of-the-art neuroimaging with an experimental analogue for trauma.

More specifically, we asked the following questions.
1) What is the neural profile of emotional memory formation and reactivation (using traumatic film clips) and how does that profile relate to subsequent voluntary versus involuntary (intrusive) memory?
2) How can we use competing task methodology shortly after a distressing event to weaken intrusive emotional memory?

We were able to look at how much the brain replayed the film clips in the rest immediately after seeing them, and to assess how this replay related to subsequent memory, both deliberately recalled memory and involuntary (intrusive) memories. This allowed us to challenge assumptions of basic models of memory (see https://www.doi.org/10.1098/rstb.2017.0209). We also made initial steps in terms of how we can use competing task methodology in the real world.

Work performed

We conducted several experiments, all with the aim to contribute to innovative, science-based therapies for trauma-related mental disorders. The main experiment involved a 3-day paradigm to examine the link between the neural profile of emotional memory consolidation and subsequent voluntary and involuntary memory for distressing film clips. To this end, we applied ‘multi-voxel correlation structure’ (a multivariate fMRI analysis technique developed to capture both the spatial and temporal information underlying complex emotional events) in order to assess the persistence of film-related activity in post-encoding and post-reactivation rest periods. Furthermore, we applied ‘multi-voxel pattern analysis’ to decode the reoccurrence of ‘hotspot’ moments (the worst moments that are likely to come back as intrusions in the following week) in post-encoding brain activity. This enabled us to relate the degree to which film-specific neural activity patterns persist during post-film rest periods to how well individuals remember details of the clip (voluntary recall) a week later, and to the frequency of intrusive memories that they recorded in a daily diary.

The results of this work have been presented at several national and international conferences, e.g. the 25th annual meeting of the Cognitive Neuroscience Society in Boston, and will soon be submitted for publication in a scientific journal. A main theory paper on the malleability of emotional memory was also published in the Philosophical Transactions of the Royal Society B (https://www.doi.org/10.1098/rstb.2017.0209). Another theoretical paper on how cognitive science has contributed to our understanding of the development and treatment of intrusive memories of trauma was published in Clinical Psychology Review (https://doi.org/10.1016/j.cpr.2018.08.005).

In addition, we continue the development of new analytical tools to address the first question in greater depth, asking about the nature of the possible dissociation between involuntary and voluntary memory. This will help us in the future to better understand neural mechanisms underlying the weakening of involuntary emotional memory.

Another, more translational, experiment looked at how we can use competing task methodology shortly after a distressing event to weaken intrusive emotional memory. It investigated the feasibility of delivering such interventions via people\'s smartphones during critical time-windows of memory malleability (Figure 1). This experiment provided the necessary groundwork for ongoing studies in Sweden on the scalability of simple-to-deliver psychological interventions for trauma-related symptoms.

Exploitation of the results includes a contribution to our understanding of trauma-related symptoms and psychological treatment innovation. Regular meetings between scientists and clinicians alongside public engagement activities foster this.

Final results

The project has explored – for the first time – a neural marker for the consolidation of memory for complex emotional events. Trauma affects many people worldwide, and the need for effective, simple-to-deliver interventions is high. Our findings contribute to our understanding of trauma-related symptoms and may inspire psychological treatment innovation.

Website & more info

More info: https://www.mrc-cbu.cam.ac.uk/people/renee.visser/.