Memory suppression trades prolonged fear and sleep-dependent fear plasticity for the avoidance of current fear

Abstract

Sleep deprivation immediately following an aversive event reduces fear by preventing memory consolidation during homeostatic sleep. This suggests that acute insomnia might act prophylactically against the development of posttraumatic stress disorder (PTSD) even though it is also a possible risk factor for PTSD. We examined total sleep deprivation and memory suppression to evaluate the effects of these interventions on subsequent aversive memory formation and fear conditioning. Active suppression of aversive memory impaired retention of event memory. However, although the remembered fear was more reduced in sleep-deprived than sleep-control subjects, suppressed fear increased, and seemed to abandon the sleep-dependent plasticity of fear. Active memory suppression, which provides a psychological model for Freud's ego defense mechanism, enhances fear and casts doubt on the potential of acute insomnia as a prophylactic measure against PTSD. Our findings bring into question the role of sleep in aversive-memory consolidation in clinical PTSD pathophysiology.

The Fear‐avoidance Components Scale (FACS): Development and Psychometric Evaluation of a New Measure of Pain‐related Fear Avoidance

“…Those in the Extreme severity group also reported more severe insomnia symptoms than patients in all the other severity levels. These results correspond with previous FA literature which has demonstrated a relationship between patient‐reported disability, depressive symptoms, and insom‐nia . A number of earlier studies have found a relationship between FA and pain intensity but, after correcting for type I error, pain intensity was not significantly different among the FACS severity groups.…”

“…Both the CMPD and psychiatric evaluation pain patient samples were assessed for demographic information and completed the FACS. Patients with CMPD also completed a battery of psychosocial PRO measures of pain intensity,perceived disability, depressive symptoms, and insomnia, which have been shown in previous studies to be associated with FA. The pain visual analogue scale (pain VAS) is scored from 0 to 10 and assessed each patient's pain level in response to his or her injury.…”

Effects of sleep on memory for conditioned fear and fear extinction.

“…They therefore suggested that posttraumatic insomnia might adaptively serve to diminish the generalization of conditioned fear that could follow trauma. However, in a subsequent study (Kuriyama, Honma, Yoshiike, & Kim, 2013), when these same investigators added an active memory suppression procedure (directed forgetting) following encoding on the same task, TSD produced a generalized increase rather than decrease in physiological fear expression, while TSD following directed remembering of the fearful stimuli replicated the previously observed generalized decease in fear expression upon recall testing. These authors attributed this differing effect to interference with hippocampal processing of context and prefrontal regulation of amygdala responses that was produced by the directed forgetting procedure at encoding.…”

Suppression-induced forgetting diminishes following a delay of either sleep or wake

“…It has further been shown that sleep after directed forgetting instructions during the encoding of emotional film clips increased physiological stress responses while watching images from these films during a subsequent re-test, without affecting explicit memory performance (Kuriyama, Honma, Yoshiike, & Kim, 2013). This indicates that emotional processing during sleep differs depending on if participants are instructed to remember or to suppress during encoding.…”