Peritraumatic Neural Processing and Intrusive Memories: The Role of Lifetime Adversity

Better together: A systematic review of studies combining magnetic resonance imaging with ecological momentary assessment

Social neuroscientists often use magnetic resonance imaging (MRI) to understand the relationship between social experiences and their neural substrates. Although MRI is a powerful method, it has several limitations in the study of social experiences, first and foremost its low ecological validity. To address this limitation, researchers have conducted multimethod studies combining MRI with Ecological Momentary Assessment (EMA). However, there are no existing recommendations for best practices for conducting and reporting such studies. To address the absence of standards in the field, we conducted a systematic review of papers that combined the methods. A systematic search of peer-reviewed papers resulted in a pool of 11,558 articles. Inclusion criteria were studies in which participants completed (a) Structural or functional MRI and (b) an EMA protocol that included self-report. Seventy-one papers met inclusion criteria. The following review compares these studies based on several key parameters (e.g., sample size) with the aim of determining feasibility and current standards for design and reporting in the field. The review concludes with recommendations for future research. A special focus is given to the ways in which the two methods were combined analytically and suggestions for novel computational methods that could further advance the field of social neuroscience.

Hitting the Rewind Button: Imagining Analogue Trauma Memories in Reverse Reduces Distressing Intrusions

Background

Intrusive re-experiencing of trauma is a core symptom of posttraumatic stress disorder. Intrusive re-experiencing could potentially be reduced by 'rewinding', a new treatment approach assumed to take advantage of reconsolidation-updating by mentally replaying trauma fast-backward.

Methods

The present analogue study was the first to investigate 'rewinding' in a controlled laboratory setting. First, 115 healthy women watched a highly aversive film and were instructed to report film-related intrusions during the following week. Twenty-four hours after film-viewing, participants reporting at least one intrusion (N = 81) were randomly allocated to an intervention (fast-backward, or fast-forward as active control condition) or a passive control condition. Intervention groups reactivated their trauma memory, followed by mentally replaying the aversive film either fast-backward or fast-forward repeatedly.

Results

Results indicate that replaying trauma fast-backward reduced intrusion load (intrusion frequency weighted for intrusion distress) compared to the passive group, whereas replaying fast-forward did not. No above-threshold differences between fast-backward and fast-forward emerged.

Conclusion

Present findings strengthen the view that 'rewinding' could be a promising intervention to reduce intrusions.

Workplace Trauma in a Digital Age: The Impact of Video Evidence of Violent Crime on Criminal Justice Professionals

High-quality video and audio recordings of violent crimes, captured using now ubiquitous digital technologies, play an increasingly important role in the administration of justice. However, the effects of exposure to gruesome material presented in this form on criminal justice professionals who analyze, evaluate, and use this potentially traumatic content in the context of their work, are largely unknown. Using long interviews and constructivist grounded theory, this qualitative study sought to explore experiences of exposure to video evidence of violent crime among Canadian criminal justice professionals. Sixteen individuals including police, lawyers, judges, psychiatrists, law clerks, and court reporters volunteered to participate in qualitative long interviews asking about workplace exposures to violent videos. Themes identified address the ubiquity of video evidence of violent crime; proximity to violence through video; being blindsided through lack of preparedness for violent content; repeated exposures through multiple and protracted viewings; insufficient customary methods for self-protection; and the enduring impact of exposure to videoed violence. We determine that criminal justice professionals are increasingly and repeatedly presented with deeply disturbing imagery that was once imperceptible or unknowable and thus previously held at a greater distance. Elements of what is newly visible and audible in video evidence of violent crime create a new emotional proximity to violence that potentially increases the risks of secondary trauma and underscores the need for improved safety measures.

Lonely in the Dark: Trauma Memory and Sex-Specific Dysregulation of Amygdala Reactivity to Fear Signals

Loneliness exacerbates psychological distress and increases the risk of psychopathology after trauma exposure. However, it is still unclear whether a lack of social connectedness affects trauma-related intrusions and the neural processing of fear signals. Moreover, it is uncertain, whether loneliness plays a different role in women and men. A prestratification strategy is used and n = 47 (n = 20 women) healthy lonely individuals and n = 35 controls (n = 18 women) are recruited. Participants are exposed to an experimental trauma and evoked intrusive thoughts in daily life are monitored for three consecutive days. Functional magnetic resonance imaging is used to assess neural habituation to fearful faces and fear learning (conditioning and extinction) prior to trauma exposure. The results reveal a significant interaction between loneliness and sex such that loneliness is associated with more intrusions in men, but not in women. A similar pattern emerges at the neural level, with both reduced amygdala habituation to repeated fearful faces and amygdala hyperreactivity during the conditioning of fear signals in lonely men. The findings indicate that loneliness may confer vulnerability to intrusive memories after trauma exposure in healthy men and that this phenotype relates to altered limbic processing of fear signals.

Neurobiological Changes in Posttraumatic Stress Disorder and Their Reversibility by Psychotherapy

Abstract. Background: Posttraumatic stress disorder (PTSD) is a debilitating illness associated with distressing symptoms and a high societal burden. Objective: To investigate the neurobiological underpinnings of PTSD to improve our understanding of this disorder and its treatment. Methods: This article reviews currently researched mechanisms that can explain the development of PTSD symptoms. It presents key findings on neural (i. e., brain functioning and brain structure), neuroendocrine (i. e., noradrenergic and hypothalamic-pituitary-adrenal axis activity), and related (epi)‌genetic changes in individuals with PTSD. Furthermore, it presents preliminary research examining the reversibility of these alterations during psychotherapeutic treatment. Results: PTSD is characterized by specific neurobiological alterations, with preliminary findings indicating that at least some of these may normalize during psychotherapy. Discussion: A multidimensional perspective on the development, maintenance, and treatment of PTSD has the potential to improve our understanding of the causal processes underlying the disorder and may ultimately inform the conception of novel treatments.

Insular cortex modulates social avoidance of sick rats

Avoidance of sick individuals is vital to the preservation of one's health and preventing transmission of communicable diseases. To do this successfully, one must identify social cues for sickness, which include sickness behaviors and chemosignals, and use this information to orchestrate social interactions. While many social species are highly capable with this process, the neural mechanisms that provide for social responses to sick individuals are only partially understood. To this end, we used a task in which experimental rats were allowed to investigate two conspecifics, one healthy and one sick. To imitate sickness, one conspecific received the viral mimic Polyinosinic:polycytidylic acid (Poly I:C) and the other saline. In a 5-minute social preference test, experimental male and female adult rats avoided Poly I:C treated adult conspecifics but did not adjust social interaction in response to Poly I:C treated juvenile conspecifics. Seeking a neural locus of this behavior, we inhibited the insular cortex, a region necessary for social behaviors directed toward conspecifics in distress. Insular cortex inactivation via administration of the GABAA agonist muscimol to experimental rats prior to social preference tests eliminated the preference to avoid sick adult conspecifics. These results suggest that some aspect of conspecific illness may be encoded in the insular cortex which is anatomically positioned to coordinate a situationally appropriate social response.

COVID-19-related distress is associated with analogue PTSD symptoms after exposure to an analogue stressor

Background: The COVID-19 outbreak in early 2020 was associated with an immediate increase in mental health problems in a significant percentage of the general population. Therefore, it is crucial to investigate how the COVID-19 pandemic - as a psychosocial stressor - affected the aetiological processes of mental disorders. Previous research has shown that stress potentiates associative (fear) learning and analogue symptoms of posttraumatic stress disorder (PTSD) and that analogue PTSD symptoms can emerge in response to associative learning. Objective: We investigated whether distress in response to the COVID-19 outbreak support the development of intrusions and rumination after exposure to a non-COVID-19-related analogue trauma. Moreover, we examined if these effects are mediated by the strength of associative learning during analogue trauma. Method: 122 undergraduate university students participated in an online experiment between March and July 2020. They completed questionnaires measuring distress and rumination related to the COVID-19 outbreak. On a subsequent day, they went through an associative learning task, in which neutral stimuli were paired with the appearance of a highly aversive film clip. Subjective ratings were assessed as indicators of associative learning. On the next day, participants documented film-related intrusions and rumination. Results: COVID-19-related distress but not rumination was associated with post-film intrusion and rumination load. These effects were mediated by associative learning. Conclusions: The current findings are in line with the assumptions that stress enhanced both associative learning and PTSD symptoms. Specifically, they indicate that prolonged psychosocial stress - like during the COVID-19 outbreak - is linked to individual differences in memory processing of aversive events. Further confirmatory research is needed to replicate these results.

Peritraumatic dissociation revisited: associations with autonomic activation, facial movements, staring, and intrusion formation

BACKGROUND

Peritraumatic dissociation is purported to emerge together with attenuated autonomic arousal, immobility, and staring. However, empirical evidence is scarce and heterogeneous. Moreover, it is still a matter of debate whether these responses predict intrusion formation.

OBJECTIVE

The present trauma-analogue study examined associations between peritraumatic dissociation, autonomic activation, facial movements, staring, and intrusion formation.

METHOD

Seventy-one healthy women watched a highly aversive film, while autonomic activation (heart rate, respiratory sinus arrhythmia, skin conductance level), facial movements (temporal variations in corrugator electromyography), and staring (fixation duration, tracklength) were assessed. Afterwards, participants rated the intensity of dissociation during film viewing and reported intrusions and associated distress in a smartphone application for 24 hours.

RESULTS

Peritraumatic dissociation was linked to higher autonomic arousal (higher heart rate and, on a trend-level, lower respiratory sinus arrhythmia), increased facial movements, and staring (lower tracklength). Peritraumatic dissociation, higher autonomic arousal (higher heart rate and lower respiratory sinus arrhythmia), staring (higher fixation duration), and, on a trend-level, more facial movements were linked to higher intrusion load (number x distress of intrusions) and together explained 59% of variance. Skin conductance level was neither linked to peritraumatic dissociation nor intrusion load.

CONCLUSIONS

Our results suggest that, at low-dissociation-levels observed in trauma-analogue studies, peritraumatic dissociation may occur together with heightened autonomic arousal and facial movements, indexing increased negative affect. Staring might, irrespectively of dissociation-levels, serve as objective marker for dissociation. Together, peritraumatic dissociation and its psychophysiological correlates might set the stage for later intrusion formation.