bluuebunny/crossref_metadata_2025_split huggingface dataset:
0065 Determining the Impact of Extended Wakefulness on Memory Retention
Authors: Varghese Anju , Kurinec Courtney , Hinson John , Whitney Paul , Satterfield Brieann 
Published: April 2024

Abstract

Introduction
It has been well-established that the rate of forgetting slows if learning is followed by a period of sleep versus wake. Although several studies compared rates of retention for material learned before sleep or sleep loss, none have explicitly examined how extended wake, without intervening sleep, impacts the rate at which information is forgotten. To explore this further, we investigated the effects of sleep deprivation on memory retention over extended wakefulness in dayshift (DS) versus nightshift (NS) participants.

Methods
N=22 adult shift workers (DS: n=17 and NS: n=5; aged 38.3±8.9 years; 12 females) participated in a 36-hr in-laboratory study. They adhered to their habitual wake time (DS: 5:50am; NS: 1:15pm) at home and arrived at the laboratory at 8:00am (DS)/8:00pm (NS). After a 2-hr acclimation period, participants followed a 24-hr constant routine protocol, which included continuous wakefulness. During the study, participants completed a memory task requiring the memorization of 20 nouns, ranging from 4-6 letters. The words were each individually presented on a computer screen for 10 sec. Recall sessions occurred immediately (session 1; 1+ hrs awake), 1 hr (session 2; 2+ hrs awake) and 24 hrs (session 3; 25+ hrs awake) post-memorization. The variable of interest is the proportion of words correct.

Results
A mixed-effects ANOVA, with fixed effects of session (1-3), shift (day vs. night), and their interaction, controlling for age, and a random intercept for participants, showed a significant main effect of session on the proportion of words correct (F[2,38]=36.65, p&lt; 0.001). Overall, the proportion of correctly recalled words decreased across sessions, with performance decreasing 12.5% from immediate to 1-hr, 18.8% from 1-hr to 24-hr, and 29.0% overall from immediate to 24-hr. Shift type and age did not significantly affect performance (p&gt;0.05).

Conclusion
The outcomes of this study replicated previous findings demonstrating the degradation of memory recall under the influence of sleep deprivation. The pattern of performance aligns with the conventional forgetting curve, in which forgetting occurs rapidly soon after learning, typically within the first hour, with the rate gradually decreasing over time. Future research will examine if continuous wakefulness exacerbated this memory decline.

Support (if any)
CARE Fund FY22-POP-02; HSSA; ARO W911NF2210223
0073 Do Slow Wave Sub-types Serve Distinct Roles in Sleep Homeostasis and Plasticity?
Authors: Noh Eunsol , Lokhandwala Sanna , Spencer Rebecca 
Published: April 2024

Abstract

Introduction
Recent research distinguishes two slow wave (SW) subtypes: slower (SSW) and faster slow waves (FSW). Early research on these subtypes suggests that FSW positively correlate with sleep pressure, while SSW are associated with memory. Developmental data from children who nap provide an opportunity to test this distinction. Prediction 1: If FSW are associated with sleep pressure, we expect more FSW during overnight sleep when children do not nap compared to overnight sleep following daytime naps. Prediction 2: If SSW are associated with memory, we expect stronger and more synchronized coupling between spindles (SP) and SSW compared to FSW, reflecting memory processing.

Methods
This is a secondary analysis of data from 25 children (3-5 yrs). Children participated in two conditions; they either napped (NO) or stayed awake (WO) during the daytime nap interval. The nap and subsequent overnight sleep in both conditions was PSG-recorded. SWs (0.5-4 Hz) and SPs (10.3-13.3 Hz) were detected during NREM sleep in the frontal region. To distinguish between slow and fast SWs, the transition frequency from the down-to-up state of SWs was utilized. Coupling amount (strength) and direction of coupling (phase) were quantified for both SSW-SP and FSW-SP coupling.

Results
Prediction 1: A higher occurrence of FSW were observed during WO compared to NO (t(24)=-2.70, p=0.01). However, after adjusting for NREM sleep duration, FSW density did not differ between NO and WO (p=0.75). Prediction 2: SSW-SP coupling strength was lower compared to FSW-SP coupling strength during WO (t(24)=-2.43, p=0.02), but there were no differences in the NO condition (p=0.25). Additionally, there were no significant differences in the coupling phase between SSW-SPs and FSW-SPs in either overnight bout (p&gt;0.45).

Conclusion
Increased sleep pressure (nap absence) did not directly affect FSW density. Instead, the absence of naps extended NREM sleep duration, elevating FSW occurrence. Moreover, SSW-SP coupling was weaker than FSW-SP coupling and only during WO, contrary to our prediction that SSW are associated with learning. While it is possible that SSW and FSW functionality is still developing at this age, these data fail to support predictions of the distinct role of SW subtypes.

Support (if any)
0074 Sleep Slow Oscillations Differ in Depth Profiles Based on Their Coupling with Spindles: A Classification Study
Authors: Dey Sounak , Malerba Paola , Mednick Sara C 
Published: April 2024

Abstract

Introduction
Slow oscillations (SOs) are large amplitude events in the electroencephalogram and contribute to sleep functions including homeostasis and consolidation of episodic memory. Complexes of one SO and one sleep spindle, where a spindle follows an SO trough within a short delay, are causally connected to sleep-dependent episodic memory improvement. In this study, we compare the cortical-subcortical brain currents that underlie SOs paired to spindles (SO+) and unpaired SOs (SO-), with the goal of identifying whether networks of activations are different in the two cases. This knowledge is essential to understanding the mechanisms of memory consolidation across brain regions.

Methods
Full-night polysomnography data (64 channel EEG) was acquired in the Mednick Lab for 22 typical young adult participants. Individual SOs and spindles were detected with in-house algorithms at every EEG channel. SO current sources at multiple time instances were found using source estimation software (Brainstorm) and encoded in a matrix representation of region-by-time, where each matrix was labeled as SO+ or SO-. Region-by-time features with strongest differentiation between SO+ and SO- were identified with multivariate feature ranking; classification with K-nearest neighbors and random forest evaluated with Matthew’s Correlation Coefficient (MCC) tested differentiability in a pooled dataset. We analyzed light (S2) and deep NREM (SWS) sleep separately.

Results
All classification algorithms achieved high MCC scores, suggesting structural differentiation between SO+/SO-. Within-individual models did not achieve high MCC scores when used to classify another individual’s SOs, refuting generalizability across subjects. Subcortical/cortical activity in SO+ vs. SO- was also found to be distinguishable up to 1 second before the SO trough. Additional analysis showed overall higher region-by-time feature interdependence underlying SO+, with the most significant features being the bilateral cortex, hippocampus, putamen, and pallidum.

Conclusion
Successful classification of SO+/SO- indicates the presence of structural differences in cortical-subcortical activation during SO that are spindle-coupled compared to uncoupled. Combined with feature analysis identifying distinct network activations in coupled vs uncoupled SOs, our study suggests a potential functional difference. Ongoing work includes investigating the various feature dependencies that exist within our dataset as well as conducting confirmatory analyses in a separate data subset.

Support (if any)
0079 Preliminary Analysis Reveals Link Between Visual Attention and Sleep Duration in Alzheimer's Disease
Authors: Rempe Maggie , Garrison Grant , Springer Seth , Glesinger Ryan , Okelberry Hannah , Petts Aubrie , Embury Christine , Wilson Tony 
Published: April 2024

Abstract

Introduction
Sleep disturbances have been shown to relate to the development of Alzheimer’s disease (AD) and its associated cognitive deficits, including visual attention function. Here, we investigated the potential interactive and additive effects of sleep disruption and AD on visual attention performance and its underlying neural mechanisms.

Methods
Preliminary analysis included 33 participants, 10 patients on the AD spectrum (mild cognitive impairment (MCI) and AD; 7 females; Mage: 70.24) and 23 cognitively-healthy older adults (17 females; Mage: 67.47). Participants completed a visual search task during magnetoencephalography (MEG). Participants also wore an Actigraph device on their non-dominant wrist for a two-week period. Actigraph data were cleaned using sleep diaries and analyzed using the Cole-Kripke algorithm. Total sleep time (TST) was calculated for each night of sleep and averaged across all nights of sleep collected. The MEG data were transformed into the time-frequency domain and significant task-related oscillatory responses were source-imaged using a beamformer.

Results
Behavioral analysis of the visual search task revealed a significant condition effect, such that reaction times (RT) in the conjunctive trials were significantly longer than those in the feature condition (p &lt; .001). There was a trending group-by-condition interaction on RT (p = .080), such that patients on the AD spectrum showed larger differences in reaction times between conditions than healthy controls. Additionally, there was a significant group by TST interaction on RT (p &lt; .001) showing that patients on the AD spectrum with less sleep had longer RT, while there was no such relationship in the controls. Regarding the MEG data, we observed robust neural responses in theta, alpha, and beta frequency bands. Analysis of source-imaged neural responses in the alpha range revealed significant conditional differences in the right posterior temporal lobe (p &lt; .005), a significant group-by-condition interaction in the right temporoparietal junction (TPJ; p &lt; .005), and interestingly, a group-by-TST interaction on conditional differences in alpha power (p &lt; .005) in right occipital and cerebellar regions.

Conclusion
Our preliminary results show key relationships between total sleep time, visual attention behavioral performance, and neural recruitment, and how these relationships may differ in AD spectrum conditions.

Support (if any)
R01-MH116782, R01-MH118013
0082 Sleep Health and Daytime Cognitive Function: Data from the National Sleep Foundation Sleep in America Poll
Authors: McNeil Kiley , Kennedy Kathryn , Gorovoy Suzanne , Killgore William , Dzierzewski Joseph , Grandner Michael 
Published: April 2024

Abstract

Introduction
Previous studies have shown that poor sleep is generally associated with daytime dysfunction. But few studies have examined this relationship in the general population across many dimensions of sleep health and it is not clear which sleep variables are most salient.

Methods
Data were collected as part of the National Sleep Foundation Sleep In America Poll. The population-based sample (N=1,042) provided data on a range of sleep questions. For the present analyses, self-reported difficulty concentrating during the day was examined as a nominal outcome (none vs occasional or frequent), with population-weighted regression analyses adjusted for age, sex, race/ethnicity, education, income, and PHQ2 depression score. Independent variables included sleep satisfaction, feeling refreshed, daytime energy, difficulty falling, frequent nighttime awakenings, difficulty resuming sleep, satisfaction with weekday and weekend sleep duration, ability to feel relaxed, overall sleep quality, weekday and weekend bedtime, waketime, time in bed, and sleep duration, perceived sleep need, and days/week (0-7) of: feeling well-rested, having trouble falling or staying asleep, sleep impacts functioning, daytime sleepiness, and sleep medication use. Bonferonni correction (0.05/26) was used.

Results
The following were associated with frequent daytime cognitive problems: poor sleep quality (RRR=17.9), fewer days well rested (RRR=0.66/day), and more days with difficulty falling asleep (RRR=1.56), difficulty staying asleep (RRR=1.47/day), days sleep impacts functioning (RRR=1.78/day), and days of daytime sleepiness (RRR=1.22/day), less sleep duration on weekdays (RRR=0.58/day) and more sleep debt (RRR=1.65/hr), low sleep satisfaction (RRR=33.93), rarely feeling refreshed (RRR=34.68), low energy (RRR=70.41), severe difficulty falling asleep (RRR=19.23), waking up (RRR=15.63), resuming sleep (RRR=12.86) and feeling relaxed (RRR=65.66), and dissatisfaction with sleep duration on weekdays (RRR=45.15) and weekends (RRR=28.42). In a stepwise regression model examining daytime concentration difficulties as an ordinal variable, after adjusting for covariates, the variables that explained the most unique variance were (in order) days/week sleep impacts functioning, ability to become relaxed, daytime energy, and difficulty waking in the night.

Conclusion
Many indicators of sleep health were associated with daytime dysfunction, implicating sleep duration, quality, efficiency, and daytime effects of sleep. Efforts might ideally focus on the daytime impacts of sleep rather than nighttime experiences.

Support (if any)
0083 You Don’t Snooze, You Lose (Awareness): Sleep’s Role on Awareness of Cognition in Mild Cognitive Impairment
Authors: Costa Amy , McCrae Christina , O'Brien Jennifer , Curtis Ashley 
Published: April 2024

Abstract

Introduction
In adults with Mild Cognitive Impairment (prodromal phase of Alzheimer’s disease; MCI), the level of awareness of cognitive functioning varies significantly. A lack of awareness of cognitive functioning may interfere with monitoring of disease progression and opportunities for intervention. Therefore, understanding mechanisms associated with this relationship is critical. Given age-related changes in sleep and known relationships between sleep health and cognition, this pilot tested whether sleep moderates associations between subjective and objective cognition in older adults with MCI.

Methods
Older adults with MCI (N=46, Mage=68.2 years, SD=6.1 years, 33 women) completed one week of sleep diaries [averages of sleep onset latency (SOL), total sleep time (TST), sleep efficiency (SE)], Cognitive Failures Questionnaire (sub-scores CFQ-memory, CFQ-distractibility, CFQ-blunders), and cognitive tasks [Cambridge Brain Sciences; Polygons (processing speed), Feature Match (attention), Double Trouble (attention/inhibition), Digit Span (working memory)]. Multiple regressions tested if sleep parameters moderated associations between subjective and objective cognition, covarying for depressive symptoms and number of medical conditions.

Results
SE moderated associations between Polygons and CFQ-blunders (R2-change=.08, p=.03). Specifically, at highest SE, slower processing speed was associated with more blunder complaints (B=-.10, p=.04). Additionally, SE moderated associations between Digit Span and CFQ-distractibility (R2-change=.06, p=.03) and CFQ-blunders (R2-change=.12, p=.004). Specifically, at lowest SE, worse working memory was associated with less distractibility (B=3.01, p=.002) and blunders (B=2.45, p&lt;.001) complaints, while at highest SE worse working memory was associated with more blunder complaints (B=-2.48, p=.04).

Conclusion
Preliminary findings suggest in older adults with MCI, lower sleep efficiency may exacerbate discrepancies between objective and subjective cognition, while higher sleep efficiency may converge this relationship. Sleep efficiency should be considered to fully understand the level of awareness of cognitive functioning in older adults with MCI. Critically, these findings may help identify those at risk of further cognitive decline. While future prospective studies are warranted, present findings suggest a potential next step is to examine whether behavioral treatments for insomnia (e.g., Cognitive Behavioral Therapy for Insomnia, cognitive training) may also change the relationship between objective/subjective cognition.

Support (if any)
This research was supported in part by the University of Missouri School of Medicine TRIUMPH award (PI: Curtis).
0086 Early Evidence for Dynamic, Day-to-day Associations Between Working Memory and Sleep in Pre-adolescent Youth
Authors: Simon Katharine C , Duggan Katherine A , Galut Lia , Polk Spencer , Rao Uma , Borelli Jessica , Rahmani Amir , Mednick Sara C 
Published: April 2024

Abstract

Introduction
The transition to adolescence is marked by critical shifts in sleep, including increased variability as well as delayed bedtimes, reduced total sleep time (TST), and reduced homeostatic sleep pressure. Sleep supports healthy brain development, and insufficient sleep impairs brain development in children and adolescents. Short-term experimental manipulations of sleep disturbance and deprivation in adults leads to dysfunction in declarative and working memory. The few experimental studies in youth suggest their cognitive abilities may be more resilient to sleep loss, but these typically include only one night of sleep manipulation. Here, we examined this phenomenon across a week of data.

Methods
Data was used from eleven 9- to 13-year-olds (M = 12.52, SD = 1.4, F = 5) in an ongoing measurement burst longitudinal study spanning one year. For seven consecutive days, participants completed daily sleep diaries, and the working memory task, the O-SPAN, which consists of remembering letters intermixed with math equations. Multilevel models which adjusted for age and sex were used to examine the bidirectional associations between sleep and cognitive performance at the between and within-subjects levels.

Results
Within-subjects (daily) variation in sleep duration, relative to each child’s typical sleep duration, was related to better working memory performance at trending significance. Within-subjects (daily) variation in working memory, relative to each child’s typical working memory performance, was related to significantly longer sleep duration. There are currently no statistically significant associations at the between-subjects level.

Conclusion
Our preliminary results suggest there are within-person, dynamic fluctuations in sleep duration and working memory in adolescents. On nights when adolescents sleep better, their working memory improves (and vice versa). Our ongoing day-to-day investigation of the role of sleep on cognition (target N=60) provides insight into the nuanced role sleep plays, especially along the performance spectrum. Future analyses in this ongoing study will evaluate dependencies in the data structure across the week, as well as developmental trends in sleep-memory associations. The current results are novel and suggest longitudinal methods are critical in the analysis of sleep and cognition in development.

Support (if any)
Award to KS: NICHD/NIH K08HD107161
0087 Effects of a Dual Orexin Receptor Antagonist on Anxiety-like Behavior and Cognition in a Mouse Model of TBI
Authors: Carey Sean , Zielinski Mark , Craig John , Babb Jessica , Kaplan Gary 
Published: April 2024

Abstract

Introduction
Mild/moderate traumatic brain injuries (TBIs) often occur in the frontal cortex and can induce prolonged impairments in sleep, cognition, and anxiety. Orexin is a neuropeptide that activates two receptors that stimulate monoamine activation in the brain to induce wakefulness. We aimed to determine if a dual orexin receptor antagonist (DORA) could improve prolonged cognitive impairments in mice that received TBI.

Methods
Two-month-old male and female C57BL/6J mice were randomly assigned to treatment groups. Mice received a craniectomy and TBI in the frontal cortex by controlled cortical impact, a craniectomy only (sham), or neither. Mice received a vehicle (placebo) or DORA by gavage for 2 consecutive days 24 h, 2 wks, and 1 m after the TBI or control treatments. Two-months after the TBI or control procedures, the mice were subjected to the open field and novel object familiarization. The following day, mice were administered the vehicle or DORA, and subjected to the elevated-plus maze (EPM), open-field maze, and novel object recognition (NOR) test. Significance was set at p&lt;.05.

Results
No significant difference between the control and sham treatments were overserved in NOR. Time spent exploring the novel object vs. the familiar object was significantly increased in both control and sham groups that received the vehicle indicating intact cognition (p=0.001 and p=0.0001, respectively). However, TBI reduced time spent exploring the novel object under vehicle conditions and after DORA treatments without TBI resulting in no significant differences in novel vs. familiar object exploration. The combined DORA and TBI treatment group spent significantly greater time exploring the novel object (p=0.047), although exhibited significantly less movement duration compared to other controls (Sham Vehicle p=&lt;.0001; Control Vehicle p=&lt;.0001). No significant differences in the EPM or open-field maze were found with experimental treatments.

Conclusion
These data further implicate mild/moderate TBI in impairments in cognition. However, due to the increased immobility caused by the DORA, we cannot conclude an interaction of DORA treatment with TBI on cognition using a NOR test that is dependent on movement activity.

Support (if any)
VA SPiRE Award (GK) I21RX003722; VA Merit Award (MZ) I01BX005379