bluuebunny/crossref_metadata_2025_split huggingface dataset:
056 Effects of Simulated Shift Schedules on Visual Search
Authors: Hudson Amanda , Hinson John , Whitney Paul , Crooks Elena , Shattuck Nita , Matsangas Panagiotis , Van Dongen Hans , Honn Kimberly 
Published: May 2021

Abstract

Introduction
Visual search is important in many operational tasks, such as passive sonar monitoring in naval operations. Shift work can contribute to fatigue and task performance impairment; in particular, backward rotating shift schedules have been shown to impair vigilant attention performance. However, the impact on visual search performance, above and beyond impaired vigilant attention, is unknown. We investigated the effects of two distinct shift work schedules using a visual search task with properties of real-life visual search performance.

Methods
N=13 adult males (ages 18–39) completed a 6-day/5-night laboratory study with an acclimation day, four simulated shift days, and a recovery day. Shift days involved either a 5h-on/15h-off backward rotating schedule (n=8) or a 3h-on/9h-off fixed schedule (n=5). The visual search task was performed once per shift at varying time of day depending on shift. Participants viewed search arrays where stimuli consisted of colored letters of different shapes. Over three trial blocks of 24 trials each, participants determined if a target was present or absent among 1, 5, 15, or 30 distractors. Similarity between targets and distractors was manipulated between blocks, such that targets differed from distractors by color only, shape only, or either color or shape but not both. For each distinct target feature block, and separately for presence or absence of a target, slopes of response times regressed against number of stimuli were calculated to quantify visual search rates. Mixed-effects ANOVA was used to analyze visual search rates by shift schedule and shift day.

Results
There were no significant effects of shift schedule (all p&gt;0.30), shift day (all p&gt;0.13), or their interaction (all p&gt;0.22) on visual search rates.

Conclusion
Previous work showed degraded vigilant attention in the shift schedules considered here, especially in the backward rotating schedule, which may compromise operational performance. However, while our sample may have been too small to have adequate statistical power, we failed to identify specific impairments in visual search with statistical significance. It remains to be determined whether greater levels of fatigue, such as could be induced by total sleep deprivation, would reveal significant visual search deficits.

Support (if any)
Naval Postgraduate School award N62271-13-M-1228
057 Age-related changes in sleep impact learning-related functional connectivity in the cortico-striatal-hippocampal system
Authors: Smith Dylan , Fang Zhuo , Carrier Julie , Doyon Julien , Fogel Stuart 
Published: May 2021

Abstract

Introduction
Older adults do not consolidate newly learned motor sequences with the same efficiency compared to younger adults, and there is evidence that enhanced consolidation by sleep is also impaired with age. It is known that brain activity in the hippocampal-cortical-striatal network is important for off-line consolidation of motor-sequences, however, the intricacies of how communication within this network is altered by sleep in order to facilitate consolidation is not known.

Methods
In this study, 37 young and 49 older individuals underwent resting state MRI before training on a MSL task, as well as after training, and then once again, after either a nap or a period of awake rest.

Results
Preliminary analysis showed a significant difference in functional communication (FC) in the hippocampal-cortical-striatal network, with younger subjects showing increased FC compared to younger individuals. Follow-up analyses revealed this effect was driven by younger subjects who showed an increase in FC between striatum and motor cortices, as well as older subjects who showed decreased FC between hippocampus, striatum, and precuneus. Therefore, an opposite effect of sleep was observed in younger vs. older participants, where young participants primarily showed increased communication in the striatal-motor network and older participants showed decrease in key nodes of the default mode network.

Conclusion
This shows that changes to sleeps’ ability to optimize functional communication may disrupt sleep-enhanced MSL consolidation in old age.

Support (if any)
Canadian Institutes of Health Research
058 The interactions of Sleep, Heart Rate Variability and Aging on an Emotional Directed Forgetting Memory Task
Authors: Sattari Negin , Upadhya Anisha , Vinces Karla , Mednick Sara 
Published: May 2021

Abstract

Introduction
The ability to forget information plays an important role in our daily lives. Sleep plays a role in memory formation and as we age, sleep-quality and memory decrease. For emotional memory a drop in preference for negative stimuli is presented with aging. Heart-rate variability (HRV), a measurement of cardiac autonomic-activity, has been related to cognitive processes. It is unknown how HRV impacts sleep-dependent memory updates in older adults. Here, we investigated HRV and sleep-related emotional memory updates in the context of aging using a Directed-Forgetting (DF) paradigm.

Methods
We tested younger [N=105,18-25yr] and older adults [N=119,60-85yr]. Subjects encoded a DF Word-Paired task, in which either negatively/neutrally-valenced word-pairs were cued to-be-remembered (Retain) or forgotten (Alter) for a later test. They then took a polysomnographically-recorded (PSG) nap including HRV. Next, recognition was tested. Memory for both Retain and Alter words was measured. We compared memory, sleep-quality measured by Sleep-Efficiency (SE) and HRV, measured by normalized High-Frequency (HFnu), an indicator of parasympathetic activity. Bivariate correlations were used to measure the associations.

Results
Younger adults showed greater performance on both Retain and Alter word-pairs (p&lt;.001) with being able to better forget Alter word-pairs only for the negative-condition (p&lt;.001). Younger adults had a higher SE (p&lt;.001) and a higher HRV-HFnu in both Stage2 (p=.02) and Stage3 (p =.03). Only for older adults in the neutral-condition, we found correlations between memory and sleep [Retain: r(20)=.52, p=.01; Alter: r(20) =.51, p=.01]. Finally, among younger adults, in Stage 2, memory was related to HFnu for both neutral [Retain: r(17) = .46, p=.05] and negative-condition [Retain: r(25) = -.41, p =.03; Alter: r(25) = -.39, p =.05]. No correlations were found for older adults(all ps&gt;.11).

Conclusion
Our result indicate a possible loss of the ability to intentionally forget irrelevant information among older adults and a role for the saliency to forget irrelevant items among younger adults. In addition, aging brain may benefit from sleep only for the neutrally-valenced items; the memory biased seen in aging. Finally, for younger adults HRV may be related to memory updates and its role depends on specific sleep stages however this association is faded away with aging.
Support (if any):
072 Sleep Spindle Harmonics in Insomnia
Authors: Goldstein Michael , Haack Monika , Mullington Janet 
Published: May 2021

Abstract

Introduction
Prior research has reported NREM spectral EEG differences between individuals with insomnia and good-sleeper controls, including elevated high-frequency EEG power (beta/gamma bands, ~16-50Hz) and, to a lesser extent, elevations in sleep spindle parameters. However, the mechanisms driving these differences remain unclear. Harmonics have been observed in EEG data as spectral peaks at multiples of a fundamental frequency associated with an event (e.g., for a 14Hz spindle, the 2nd harmonic is expected to be a peak at 28Hz). Thus far, there has been very limited application of this idea of spectral harmonics to sleep spindles, even though these patterns can indeed be seen in some existing literature. We sought to build on this literature to apply spectral harmonic analysis to better understand differences between insomnia and good sleepers.

Methods
15 individuals with insomnia disorder (DSM-5 criteria, 13 female, age 18–32 years) and 15 good-sleeper controls (matched for sex, age, and BMI) completed an overnight polysomnography recording in the laboratory and subsequent daytime testing. Insomnia diagnosis was determined by a board-certified sleep specialist, and exclusion criteria included psychiatric history within past 6 months, other sleep disorders, significant medical conditions, and medications with significant effects on inflammation, autonomic function, or other psychotropic effects.

Results
Consistent with prior studies, we found elevated sleep spindle density and fast sigma power (14-16Hz). Despite no difference in beta or gamma band power when averaged across NREM sleep, time-frequency analysis centered on the peaks of detected spindles revealed a phasic elevation in spectral power surrounding the 28Hz harmonic peak in the insomnia group, especially for spindles coupled with slow waves. We also observed an overall pattern of time-locked delay in the 28Hz harmonic peak, occurring approximately 40 msec after spindle peaks. Furthermore, we observed a 42Hz ‘3rd harmonic’ peak, not yet predicted by the existing modeling work, which was also elevated for insomnia.

Conclusion
In conjunction with existing mathematical modeling work that has linked sleep spindle harmonic peaks with thalamic relay nuclei as the primary generators of this EEG signature, these findings may enable novel insights into specific thalamocortical mechanisms of insomnia and non-restorative sleep.

Support (if any)
NIH 5T32HL007901-22
077 Human activity levels reflect circadian influences independent of sleep/wake behavior
Authors: Klerman Elizabeth , McHill Andrew , Brown Lindsey , Czeisler Charles 
Published: May 2021

Abstract

Introduction
Actigraphy is a non-invasive method that allows long-term recordings of activity, light, and other variables in diverse environments. In real-world settings, activity usually has a 24-hour rhythm that may arise from sleep/wake-associated behavior and/or circadian rhythmicity. We tested for an independent circadian component using data from people living on non-24 hours “days” in the laboratory.

Methods
Data are from five inpatient studies with tightly-controlled forced desynchrony (FD) conditions. Participants (19–34 yo) were healthy by history, physical exam, laboratory tests of blood and urine, and clinical polysomnography, and did not report using prescription medicines. Caffeine-containing substances were prohibited during the study. Protocol 1: 7 participants (3 F) T-cycle (i.e., FD sleep-wake cycle duration) = 42.85h; Rest:Activity ratio 1:3.3. Protocol 2: 8 participants (3 F) T cycle =42.85h; Rest:Activity 1:2. Protocol 3: 9 participants (3 F) T cycle =28.0h; Rest:Activity 1:2. Protocol 4: 7 participants (3 F) T cycle =20.0h; Rest:Activity ratio 1:3.3. Protocol 5: 7 participants (5 F) T cycle =20.0h; Rest:Activity 1:2. At all times except during showers, participants wore an actiwatch that measured activity levels and light. Melatonin period and phase 0 (i.e., fit maximum) were computed using non-orthogonal spectral analyses. Data were analyzed relative to 3-hr Circadian Phase bins (1/8 of computed circadian period for each individual) and 3-hr Wake Duration bins. Activity data were summarized using Zero-Inflated-Poison-based statistics for each Circadian*Wake Duration bin for each individual and then across individuals within each study. Repeated measures ANOVA were conducted. Statistics were performed using SAS.

Results
For all protocols, there were significant differences (all p&lt;0.007) by individual participant, by Circadian Phase, and by Wake Duration bin, but not by the interaction term (Circadian Phase* Wake Duration). Highest levels of activity were at Circadian Phase 7.5–10.5 (~10am–1pm) and lowest values at Circadian Phase -1.5–1.5 (~midnight–3 am). Activity values were lowest at scheduled sleep times.

Conclusion
Circadian rhythms independent of sleep/wake behaviors influence activity levels and may be an important component of analyses. In individuals living on non-24-hr days (e.g., some blind people and some sighted people with Non-24-hr Sleep Disorder), it may be possible to derive circadian-based metrics.

Support (if any)
NIH K24-HL105664, P01-AG009975, T32-HL007901, K01-HL146992.
087 Gender differences in attitudes towards sleep moderate sleep hygiene behaviors
Authors: Zendels Philip , Ruggiero Aria , Peach Hannah , Gaultney Jane 
Published: May 2021

Abstract

Introduction
Attitudes towards sleep have been shown to be a predictor for sleep hygiene. Sleep hygiene is the set of behaviors and conditions that promote optimal sleep, such as avoiding arousing nighttime activities, avoiding eating too close before bed, having a dark and quiet bedroom, and having a regular sleep schedule. Previous literature indicates that there are gender differences in health attitudes. This study examined whether gender differences in sleep attitudes may explain differences in sleep hygiene.

Methods
A sample of 172 (101 males, 71 females) individuals completed surveys through Amazon’s Mechanical Turk. Sleep attitudes were assessed using the Charlotte Attitudes Towards Sleep Scale (CATS; Peach & Gaultney, 2017). Sleep hygiene was measured using the Sleep Hygiene Practice Scale (SHPS; Lin et al; 2007; Yang et al., 2010). Males were dummy coded as 0. Other data were collected surrounding sleep outcomes, health behaviors, and demographics. Linear regression analyses were ran to examine the impact of Sleep attitudes, gender, and an interaction term on each subscale of the SHPS.

Results
Sleep attitudes significantly predicted each of the components of the SHPS: arousal, eating, environment, and time (b = -3.44, -2.93, -3.80, -3.04; p&lt;.01 for each). Gender significantly predicted sleep hygiene behaviors for eating (b = -10.35, p&lt;.05) and environment (b = -15.40, p&lt;.05) only. The interaction term also significantly predicted sleep hygiene eating behaviors (b = 1.70 p&lt;.05) and environmental conditions (b = 2.91, p&lt;.05). These findings suggest that more favorable sleep attitudes lead to better sleep hygiene behaviors, and women tend to have better eating and environment related sleep hygiene behaviors. Graphs of the interactions indicated males’ sleep attitudes associated with greater differences in sleep hygiene practices, in that positive sleep attitudes predicted better eating and environment elements of sleep hygiene.

Conclusion
This exploratory research suggested that men’s sleep-related behaviors may be more sensitive to the role of sleep attitudes. Future research should explore causes for gender differences in sleep attitudes and seek ways to improve behaviors and outcomes that are most relevant for specific demographic groups.

Support (if any)
Psychological Sciences department funding
088 Irregular Sleep Patterns Predict Worse Sleep Quality and Poorer Psychosocial and Academic Outcomes
Authors: Gao Chenlu , Do Alexander , Scullin Michael 
Published: May 2021

Abstract

Introduction
While the consequences of short sleep duration are well understood, relatively little is known about how irregular sleep durations are related to daily functioning. We utilized actigraphy and self-report methods to investigate the correlates of intraindividual sleep variability in two populations.

Methods
In Study 1, N=699 adults (mean age=38.04, SD=11.65; 44.78% female) completed online questionnaires on sleep, work status, and time management. In Study 2, N=100 college students (mean age=19.08, SD=1.26; 50% female; 50% underrepresented minorities) wore actiwatches for two one-week sessions (1 month apart) and reported sleep, psychosocial functions, and academic outcomes. In both studies, variability of sleep duration was defined as the individual standard deviation (ISD) of sleep durations.

Results
In Study 1, after controlling for mean sleep duration, greater variability in sleep duration was related to shiftwork (F=8.68, p=.003), younger age (r=-.15, p&lt;.001), male gender (F=4.43, p=.036), and greater vulnerability to stress (r=.15, p=.001). Beyond mean sleep duration, variability in sleep duration also predicted poorer sleep quality (r=.25, p&lt;.001), greater sleepiness during the day (r=.10, p=.014), poorer time management (r=-.09, p=.031), lower work efficiency (r=-.14, p=.002), and more procrastination (r=.11, p=.009). In Study 2, variability in actigraphy-defined sleep duration increased as the semester progressed (ISD=1.25±0.55 hours at T1; ISD=1.57±0.80 hours at T2, t=4.64, p&lt;.001). After controlling for mean sleep duration, sleep variability was associated with greater perceived stress (r=.31, p=.002 at T1), poorer sleep quality (r=.39, p&lt;.001 at T1; r=.30, p=.003 at T2), and lower expected grades (r=-.27, p=.01 at T2). Sleep variability was unrelated to depression or perceptions of one’s overall health.

Conclusion
Keeping regular sleep habits appear just as important as average sleep duration to psychosocial, work, and academic outcomes. Sleep interventions should incorporate specific guidelines on how to promote regular sleep and employers should institute work schedules that promote regularity.

Support (if any)
This work is supported by the National Science Foundation, Psi Chi Honor Society, and the American Psychological Association.
092 Effect of the dual orexin receptor antagonist (DORA) daridorexant on behaviour upon awakening in rats and dogs
Authors: Bergamini Giorgio , Roch Catherine , Durkin Sean , Steiner Michel 
Published: May 2021

Abstract

Introduction
The ability to be fast alert and to interact with the environment without motor impairment upon waking up, is a critical feature of natural sleep. DORAs represent a new class of insomnia medications that specifically inhibit the wake-promoting effects of orexin neuropeptides. Daridorexant is a potent and selective DORA under late stage development for the treatment of insomnia. Here, we assessed the impact of sleep-promoting doses of daridorexant on rats’ and dogs’ behaviour upon forced awakening. Zolpidem (a positive GABAA receptor modulator) was used as active comparator in rats because of its known negative impact on motor functions.

Methods
Rats were woken up at different time points after oral administration of daridorexant (10, 30, 100 mg/kg) or zolpidem (30, 100 mg/kg) during their inactive phase, and repeatedly subjected to two motor tasks: 1) the rotating rod test (lasting 120 sec, at each time point) assessing gross motor skills and coordination, and 2) the forepaw grip strength test assessing fine motor skills and muscle strength. Dogs were presented with food as an external, salient stimulus, three hours after administration of daridorexant in gelatin capsules (10, 30 or 90 mg/dog) during their active phase. Behaviour and signs of muscle weakness, after having woken up, were assessed by manual inspection of video recordings and concomitant electroencephalogram/electromyogram recordings.

Results
In both the rotarod and grip tests, daridorexant treatment had no effect on motor behavior at any dose or time point tested, while zolpidem significantly reduced the time spent on the rotarod and the grip strength in a dose and time-dependent manner (N=12/group; p&lt;0.001;) (e.g. at 30 min post-dose, time spent on the rotarod was 84, 79–89 and 10–19 sec for vehicle, daridorexant and zolpidem, respectively). Dogs treated with daridorexant were able to wake up easily upon food presentation. They behaved and ate normally and did not show any signs of muscle weakness.

Conclusion
The type of sleep promoted by daridorexant is surmountable in rats and dogs and similar to physiological sleep. It allows animals to easily wake up, to behave normally without motor impairment and to respond efficiently to the environmental conditions.

Support (if any)
Funded by Idorsia Pharmaceuticals Ltd
093 Sleep and Mood Across the Menstrual Cycle in Young Women
Authors: Shuster Alessandra , Zhang Jing , Simon Katharine , Sattari Negin , Albinni Benedetta , Alzueta Elisabet , Dulai Teji , de Zambotti Massimiliano , Baker Fiona , Mednick Sara 
Published: May 2021

Abstract

Introduction
Sleep modulates mood, with adequate, good-quality sleep associated with a more positive mood. Additionally, sleep is affected by the menstrual cycle in women, with better self-reported sleep quality during non-menses, compared with pre- and during menses. The present study examines the interaction between self-reported sleep quality and mood across the menses (pre/during menses) and non-menses portion of the menstrual cycle.

Methods
10 female participants (27± 2.96) completed sleep and mood diaries over a two month period, answering questions about their nighttime sleep quality and daily mood, and also marking days of menstruation. Each morning participants indicated on a 7-point scale how their overall sleep quality was the previous night. Then, each evening, participants indicated on a 7-point scale the extent to which they felt specific positive and negative moods throughout the day. Time lag cross-correlation and linear regression models were used to determine directionality of sleep quality and mood, and interaction between sleep quality, menses status, and mood levels.

Results
Better sleep quality was associated with better mood, with prior sleep quality predicting mood, but prior mood did not predict sleep (cross-correlation time lag = 0) across menses and non-menses. Additionally, on average women reported higher levels of sleep quality and better mood during the non-menses portion of their cycle. During the non-menses portion, women reported higher levels of positive mood (happy, pleased, and joyful), which were mediated by level of sleep quality. Women also reported lower levels of negative mood (depression, frustration, anxiety, unhappiness, and overwhelmed feelings), which were similarly mediated by level of sleep quality.

Conclusion
These findings are consistent with the hypothesis that sleep modulates mood, which fluctuates over the course of a woman’s menstrual cycle. Moreover, our data suggest that perceived sleep quality impacts mood, and that the menstrual cycle affects both sleep quality and mood

Support (if any)
Supported by: RF1AG061355 (Baker/Mednick)