Memory (over)consolidation during sleep, saturation, and Post-traumatic Stress Disorder
Sleep has long been implicated in memory consolidation. Physiological events during sleep parallel the time course of memory consolidation that was first discovered by UCLA's own Kim and Fanselow. The neurochemical environment of the dreaming brain (e.g. high acetylcholine and low norepinephrine) also uniquely allows synaptic weakening (discovered in Tom O'Dell's lab at UCLA) as well as strengthening to integrate new memories into old schema. Research results from my lab and others is now hinting that some key endophenotypes of post-traumatic stress disorder may be the result of maladaptive sleep after trauma exposure that serves to only strengthen the traumatic memories. This type of sleep would saturate circuits and prevent consolidation/integration of new information that would otherwise mitigate the power of the trauma-related cues over fear, arousal, and threat detection circuits. I will describe four experiments we have conducted, outline several critical unanswered questions that remain, and suggest sleep interventions that may unseat even well-established PTSD circuits through normal sleep-dependent memory alterations during re-consolidation.