Prospective associations between intelligence, working memory capacity, and intrusive memories of a traumatic film: Potential mediating effects of rumination and memory disorganization.

BACKGROUND AND OBJECTIVES: Field research indicates that lower intelligence may predispose trauma-exposed individuals towards the development of re-experiencing symptoms. However, this assumption requires further testing in controlled prospective studies. In the current analog study, we tested whether lower fluid intelligence and lower working memory capacity (WMC) independently contribute to intrusion development. Moreover, we investigated potential mediating effects of trauma memory characteristics and trait rumination. METHODS: 118 healthy participants completed tests measuring fluid intelligence and WMC. Two days later, they were exposed to a film clip depicting traumatic events (i.e., so-called trauma film). After exposure to the film, intrusions were assessed using a diary and an intrusion triggering task. RESULTS: Our analyses revealed a negative correlation between fluid intelligence and intrusions during the intrusion triggering task. WMC did not correlate with any intrusion measure. Moreover, planned analyses did not yield any mediation effects. LIMITATIONS: We used the trauma film paradigm to examine analog posttraumatic stress symptoms. This approach limits the generalizability of our findings with regard to symptom development following real-life traumatic events. CONCLUSIONS: Our results show for the first time that higher fluid intelligence is associated with fewer intrusions of a trauma film. This association was evident for laboratory but not for ambulatory intrusions. By demonstrating this association using a prospective experimental design, our study importantly corroborates previous field research.

Differential effects of sleep on explicit and implicit memory for potential trauma reminders: findings from an analogue study.

Background: Recent findings suggest that disruptions of sleep-related memory processing are involved in the development of posttraumatic stress symptoms. More specifically, exposure to an analogue traumatic event resulted in fewer intrusive memories, when it was followed by sleep instead of continued wakefulness. However, competing evidence suggests that sleep deprivation may reduce intrusive re-experiencing. To address these conflicting accounts, we examined how sleep - as opposed to partial sleep deprivation - modulates explicit and implicit trauma memory using an analogue procedure. Methods: Healthy participants (N = 41) were assigned to a Sleep or Partial sleep deprivation group. Prior to nocturnal sleep, both groups were exposed to "traumatic" picture stories. After sleep or partial sleep deprivation, participants were subjected to tests of explicit and implicit memory for potential trauma reminders. Thereafter, participants completed an intrusion triggering task that was embedded in a distractor task. Results: Analyses revealed higher explicit memory for potential trauma reminders after sleep as compared to partial sleep deprivation. No group differences were found for implicit memory. Participants responded with fewer intrusions after sleep than following partial sleep deprivation. Conclusions: The current findings support a protective role of sleep in trauma memory processing, which may be evident after the first night of sleep post-trauma. Although more research is needed, our results corroborate the importance of promoting restful sleep in trauma-exposed individuals.

Antecedentes: hallazgos recientes sugieren que las interrupciones del procesamiento de la memoria relacionada con el sueño están involucradas en el desarrollo de los síntomas de estrés postraumático. Más específicamente, la exposición a un evento traumático análogo resultó en menos recuerdos intrusivos, cuando fue seguido por el sueño en lugar de la vigilia continua. Sin embargo, evidencia contraria sugiere que la falta de sueño puede reducir la reexperimentación intrusiva. Para abordar estos reportes en conflicto, examinamos cómo el sueño, en lugar de la privación parcial del sueño, modula la memoria de trauma explícita e implícita mediante un procedimiento análogo.Métodos: los participantes sanos (N = 41) se asignaron a un grupo de deprivación de sueño total o parcial. Antes del sueño nocturno, ambos grupos fueron expuestos a historias de imágenes 'traumáticas'. Después de la privación total o parcial del sueño, los participantes fueron sometidos a pruebas de memoria explícita e implícita para posibles recuerdos traumáticos. A partir de entonces, los participantes completaron una tarea activadora de recuerdos intrusivos, que se integró en una tarea distractora.Resultados: los análisis revelaron una mayor memoria explícita para recuerdos potencialmente traumáticos después del sueño en comparación con la privación parcial del sueño. No se encontraron diferencias de grupo para la memoria implícita. Los participantes respondieron con menos intrusiones después del sueño que después de la privación parcial del sueño.Conclusiones: Los hallazgos actuales apoyan un papel protector del sueño en el procesamiento de la memoria del trauma, que puede ser evidente después de la primera noche de sueño después del trauma. Aunque se necesita más investigación, nuestros resultados corroboran la importancia de promover el sueño reparador en personas expuestas a traumas.

Cortisol administration after extinction in a fear-conditioning paradigm with traumatic film clips prevents return of fear.

Cortisol is a stress hormone and potent modulator of learning and memory processes. If administered after learning, cortisol can enhance memory consolidation. Yet it is unknown whether cortisol administration after fear extinction learning strengthens extinction memory. Extinction is a crucial mechanism underlying psychotherapy of posttraumatic stress disorder (PTSD). The present study examined whether extinction can be enhanced by administering cortisol after extinction training. In a registered, randomized, double-blind and placebo controlled trial, 50 healthy participants were exposed to a differential fear-conditioning paradigm with neutral faces as conditioned stimuli (CS) and traumatic film clips as unconditioned stimuli (US). They received either cortisol (n = 25) or placebo (n = 25) immediately after extinction. The cortisol group showed less fear during a return of fear manipulation (reinstatement) evidenced by attenuated fear potentiated startle responses and US-expectancy ratings than the placebo group. Results indicate that cortisol administration after fear extinction strengthens extinction memory and suggest that it might be advantageous to administer cortisol subsequent to successful exposure treatment sessions.

REM theta activity predicts re-experiencing symptoms after exposure to a traumatic film.

BACKGROUND: Extensive empirical evidence indicates that sleep plays an active role in memory consolidation. Moreover, sleep has been found to preferentially enhance emotional memories and may modulate affective reactions to previously encountered stimuli. Notably, recent findings suggest that disruptions of sleep-related memory processing could be involved in posttraumatic symptom development such that sleep disturbances may accelerate symptoms of intrusive re-experiencing. METHODS: Based on this emerging evidence, we investigated whether an analogue traumatic event would result in immediate impairments of sleep quality in a group of healthy, robust sleepers. In addition, we examined associations between a specific oscillatory correlate of emotional memory consolidation processes (REM theta activity) and subsequent analogue PTSD symptoms. Thirty-three healthy participants entered the study and were exposed to either "traumatic" or neutral films. Thereafter, participants were subjected to an 8.5-hour-long nocturnal sleep opportunity under standardized laboratory conditions including full-night polysomnographic recordings. Ambulatory intrusive memories and subjective symptom ratings were assessed during a period of three consecutive days. RESULTS AND CONCLUSIONS: Our results provide partial support for impaired sleep quality after exposure to a traumatic film. Correlation analyses further reveal that a longer REM sleep duration after "traumatic" exposure predicts reduced analogue PTSD symptoms. Critically, REM theta activity selectively predicts lower re-experiencing symptoms. As previous findings suggest that REM theta activity is reduced in patients with posttraumatic stress disorder, our findings provide a new perspective on the functional role of REM sleep in trauma memory processing.

The Prospective Influence of Trait Alexithymia on Intrusive Memories: What Is the Role of Emotional Recognition Memory?

Posttraumatic stress disorder (PTSD) is often considered to be a disorder of memory as patients suffer from fragmented uncontrollable memories (intrusions) whilst experiencing difficulties in intentionally retrieving details of the traumatic event. Recent research suggests that trait-related deficits in the identification of emotional states (alexithymia) may impact emotional memory processes in a way that promotes intrusion formation in PTSD. Therefore, we investigated the influence of alexithymia on intrusive re-experiencing and emotional recognition memory in a prospective analog study. Twenty-six healthy participants took part in a laboratory experiment, which combined two independent paradigms. Participants were exposed to a traumatic film (first session) and completed an episodic memory task comprising neutral and emotional stimuli (second session). In between sessions, participants recorded intrusive memories of the film. Individuals with higher trait alexithymia (HTA) reported an increased number of intrusions on the day of film presentation. Moreover, analyses of memory performance revealed a negative correlation between alexithymia and emotional recognition memory. Further analyses suggest that reduced emotional recognition memory, as evident in individuals with HTA, may, in turn, be associated with enhanced intrusive re-experiencing. As such, the current findings provide first indications regarding the role of alexithymia in emotional learning and PTSD. Future studies should further investigate these associations as well as potential implications for the treatment of PTSD.