Beta spectral power during sleep is associated with impaired recall of extinguished fear

Background The failure to retain memory for extinguished fear plays a major role in the maintenance of post-traumatic stress disorder (PTSD), with successful extinction recall necessary for symptom reduction. Disturbed sleep, a hallmark symptom of PTSD, impairs fear extinction recall. However, our understanding of the electrophysiological mechanisms underpinning sleep’s role in extinction retention remain underdetermined. Methods We reanalyzed data from two existing datasets examining the relationship between the microarchitecture of sleep and extinction recall in healthy controls (Study 1, n = 46) and a pilot study in individuals with PTSD (Study 2, n = 12). In both studies, participants underwent a fear conditioning and extinction protocol over the course of two days, with polysomnography sleep recording occurring between conditioning and extinction. Twenty-four hours after extinction learning, participants underwent extinction recall. Power spectral density (PSD) was computed for NREM and REM sleep during both pre- and post-extinction learning. Results Increased PSD in frequencies spanning the canonical beta band during pre-extinction learning sleep were associated with worse extinction recall in healthy participants (r = .41, p = .004). Beta PSD was shown to be highly stable across three nights of sleep (NREM intraclass correlation (ICC) = 0.93; REM ICC = 0.94). Individuals with PTSD were found to have increased beta PSD compared to healthy controls (NREM: p = .038; REM: p = .007), and beta PSD correlated with extinction recall in the PTSD group at a similar magnitude to controls (r = .39). Conclusions The present findings suggest that beta band PSD may be a trait-like feature of the sleep EEG that is heightened in PTSD and associated with impaired fear extinction recall. Thus, beta PSD during sleep may reflect a trait marker for vulnerability to PTSD, specifically implicated in difficulties recalling extinguished fear.