The sleeping brain and emotional memory consolidation

: An analogue investigation into the role of sleep on intrusive memory development in PTSD. 

Abstract

Emotional memories are at the core of post-traumatic stress disorder (PTSD), therefore it has been suggested that blocking memory consolidation processes in the aftermath of trauma may reduce the chances of symptoms developing. Research from the neurosciences confirms the importance of sleep in memory consolidation, with specific consolidation interactions occurring between different sleep stages and fractions of the memory system. This review examined whether there is sufficient evidence from recent non-clinical experimental studies to support the contention that sleep deprivation in the aftermath of trauma may be an effective behavioural intervention to reduce PTSD symptomatology. The review focused on studies examining the effect of sleep on emotional declarative memory in adults. A systematic search yielded twenty-one studies that met inclusion criteria. Results from memory tasks were overall inconsistent; some studies showed support that sleep selectively enhances emotional memories or sleep deprivation impairs this consolidation process. However, other studies provided equivocal evidence or argued against a selective enhancement during sleep. Moreover, conflicting evidence emerged for a special role of rapid eye movement (REM) sleep in emotional memory consolidation. Although sleep-related differences in emotional or neutral memory performance were not always displayed, neuroimaging studies found evidence for emotional memory consolidation at the functional level. We conclude that there is presently insufficient evidence to warrant using sleep deprivation as an early intervention strategy in PTSD. Further studies examining all aspects of memory encoding, consolidation and retrieval will delineate this ongoing clinical question and several suggestions for future research are outlined.

Date of Award	2015
Original language	English
Awarding Institution	King's College London
Supervisor	Jennifer Wild (Supervisor) & Robin Morris (Supervisor)