A Review of the Relationship Between Emotional Learning and Memory, Sleep, and PTSD
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Purpose of Review
The emotional memory and learning model of PTSD posits maladaptive fear conditioning, extinction learning, extinction recall, and safety learning as central mechanisms to PTSD. There is increasingly convincing support that sleep disturbance plays a mechanistic role in these processes. The current review consolidates the evidence on the relationships between emotional memory and learning, disturbed sleep, and PTSD acquisition, maintenance, and treatment.
While disrupted sleep prior to trauma predicts PTSD onset, maladaptive fear acquisition does not seem to be the mechanism through which PTSD is acquired. Rather, poor extinction learning/recall and safety learning seem to better account for who maintains acute stress responses from trauma versus who naturally recovers; there is convincing evidence that this process is, at least in part, mediated by REM fragmentation. Individuals with PTSD had higher “fear load” during extinction, worse extinction learning, poorer extinction recall, and worse safety learning. Evidence suggests that these processes are also mediated by fragmented REM. Finally, PTSD treatments that require extinction and safety learning may also be affected by REM fragmentation.
Addressing fragmented sleep or sleep architecture could be used to increase emotional memory and learning processes and thus ameliorate responses to trauma exposure, reduce PTSD severity, and improve treatment. Future studies should examine relationships between emotional memory and learning and disturbed sleep in clinical PTSD patients.
KeywordsPTSD Sleep disorders Emotional learning Emotional memory Treatment
The writing was supported by VA RR&D CDA Grant no. 1lK2Rx002120-01 (Dr. Colvonen) and by the Office of Academic Affiliations, Advanced Fellowship Program in Mental Illness Research and Treatment, Department of Veterans Affairs (Dr. Straus). The editors would like to thank Dr. Bradley Gaynes for taking the time to review this manuscript.
Compliance with Ethical Standards
Conflict of Interest
Peter J. Colvonen, Laura D. Straus, Dean Acheson, and Philip Gehrman declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
The contents do not represent the views of the U.S. Department of Veterans Affairs or the US Government.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
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