Mental Imagery and Post-Traumatic Stress Disorder: A Neuroimaging and Experimental Psychopathology Approach to Intrusive Memories of Trauma

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.

Keywords: experimental psychopathology; flashbacks; intrusive memory; mental imagery; neuroimaging; post-traumatic stress disorder; psychological trauma; trauma film paradigm.

Figure 1

Diagram of the general procedure of the trauma film paradigm. Participants view a distressing film as an analog of a traumatic event. Over the following week they record any intrusive memories of the film in a diary. This allows for investigation of baseline differences affecting intrusive memory development, or tasks that might increase/decrease later intrusive memories.

Figure 2

A proposed clinical-neuroscience framework of intrusive memories breaking intrusive memories into five component parts.

Figure 3

Diagram mapping the patient experience of an intrusive memory onto the brain. The components of our clinical-neuroscience framework are in the center, surrounded by the different brain areas involved.