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Yack, L. M.

Publications and source records attributed to Yack, L. M..

2 recordsLinked to original sources
bioRxiv2026

Sleep and emotional memory: translating neural response at encoding to memory accuracy in men and women with and without PTSD

BackgroundGrowing evidence suggests that sleep plays an important role in PTSD outcomes, potentially due to its influence on emotional memory consolidation, though these mechanisms remain unknown. This study sought to test the hypotheses that sleep neurophysiology, PTSD status, and sex moderates the degree to which the late positive potential (LPP) mediates memory accuracy for affective visual stimuli. MethodsN = 39 participants (18 female) viewed 75 negative and 75 neutral IAPS images while EEG was recorded. After viewing the images, participants took a two-hour long nap which was followed by a memory assessment. Memory accuracy was measured using d = Z(hit rate) - Z(false alarm rate), where hit rate refers to the proportion of images seen during the memory assessment that are correctly identified as being previously seen, false alarm rate refers to the proportion of images seen during the memory assessment that are incorrectly identified as being previously seen, and Z() is the inverse cumulative distribution function of the standard normal distribution function. ResultsThe early (300 - 1000 ms) and late (1000 - 1500 ms) LPP mediated enhanced discrimination accuracy for emotional compared to neural stimuli (d) (ps < 0.001). The association between the late LPP and d was moderated by sleep such that the association was stronger when participants spent proportionately more time in N3 and REM (p = 0.02). The differences in reactivity between emotional and neutral images for both the early and late LPP were attenuated in PTSD+ individuals vs. controls (ps < 0.001). Despite mediation results showing greater d for emotional compared to neutral stimuli, women showed overall worse memory accuracy for negative compared to neutral stimuli (p < 0.001) whereas men showed no difference (p = 0.64). ConclusionsN3 and REM sleep play a critical role for memory of stimuli that produce large and sustained neural responses. PTSD is marked by a diminished ability to distinguish between negative and neutral information. More research is critical to understand sex effects on emotional memory.

neuroscience↗
bioRxiv2022

Sleep spindles favor emotion regulation over memory consolidation of stressors in PTSD

Posttraumatic stress disorder (PTSD) is a trauma-induced debilitating condition, with symptoms that revolve around a declarative memory of a severe stressor. How does the brain process declarative and emotional information of stressors in PTSD? We evaluated the role of NREM sleep spindles in this process after exposure to laboratory stress, in a cohort of human subjects with different levels of PTSD symptoms. Subjects performed two laboratory visits: 1) a stress visit which involved exposure to negatively-valent images in the morning and 2) a control visit. In both visits subjects had a sleep/nap opportunity in the afternoon monitored via electroencephalography (EEG). In the stress visit, self-reported anxiety confirmed elevated stress immediately after stressor exposure (pre-sleep) that decayed to control levels post-sleep. An image recall session took place in the late afternoon. Overall, NREM2 spindle rates were elevated in the stress visit as compared to the control visit. This increase in NREM2 spindle rates, especially over occipital cortex, was significantly greater in subjects with high vs. low PTSD symptoms. However in high-PTSD subjects, NREM2 spindle rates correlated with poorer recall accuracy of stressor images as compared to lower symptomatic individuals while surprisingly correlating with a greater reduction in anxiety levels across sleep. Thus although NREM2 spindles are known to play a role in declarative memory processes, our findings highlight an important role of NREM sleep in favoring sleep-dependent anxiety regulation over memory consolidation after exposure to stressors in PTSD and shed new light on the function of NREM2 spindles in PTSD.

neuroscience↗