bluuebunny/crossref_metadata_2025 huggingface dataset:
White Matter Alteration Following SWAT Explosive Breaching Training and the Moderating Effect of a Neck Collar Device: A DTI and NODDI Study
Authors: Yuan Weihong , Dudley Jonathan , Slutsky-Ganesh Alexis B , Leach James , Scheifele Pete , Altaye Mekibib , Barber Foss Kim D , Diekfuss Jed D , Rhea Christopher K , Myer Gregory D
Published: May 2021

Introduction

Special Weapons and Tactics (SWAT) personnel who practice breaching with blast exposure are at risk for blast-related head trauma. We aimed to investigate the impact of low-level blast exposure on underlying white matter (WM) microstructure based on diffusion tensor imaging (DTI) and neurite orientation and density imaging (NODDI) in SWAT personnel before and after breacher training. Diffusion tensor imaging is an advanced MRI technique sensitive to underlying WM alterations. NODDI is a novel MRI technique emerged recently that acquires diffusion weighted data from multiple shells modeling for different compartments in the microstructural environment in the brain. We also aimed to evaluate the effect of a jugular vein compression collar device in mitigating the alteration of the diffusion properties in the WM as well as its role as a moderator on the association between the diffusion property changes and the blast exposure.

Materials and Methods

Twenty-one SWAT personnel (10 non-collar and 11 collar) completed the breacher training and underwent MRI at both baseline and after blast exposure. Diffusion weighted data were acquired with two shells (b = 1,000, 2,000 s/mm2) on 3T Phillips scanners. Diffusion tensor imaging metrices, including fractional anisotropy, mean, axial, and radial diffusivity, and NODDI metrics, including neurite density index (NDI), isotropic volume fraction (fiso), and orientation dispersion index, were calculated. Tract-based spatial statistics was used in the voxel-wise statistical analysis. Post hoc analyses were performed for the quantification of the pre- to post-blast exposure diffusion percentage change in the WM regions with significant group difference and for the assessment of the interaction of the relationship between blast exposure and diffusion alteration.

Results

The non-collar group exhibited significant pre- to post-blast increase in NDI (corrected P < .05) in the WM involving the right internal capsule, the right posterior corona radiation, the right posterior thalamic radiation, and the right sagittal stratum. A subset of these regions showed significantly greater alteration in NDI and fiso in the non-collar group when compared with those in the collar group (corrected P < .05). In addition, collar wearing exhibited a significant moderating effect for the alteration of fiso for its association with average peak pulse pressure.

Conclusions

Our data provided initial evidence of the impact of blast exposure on WM diffusion alteration based on both DTI and NODDI. The mitigating effect of WM diffusivity changes and the moderating effect of collar wearing suggest that the device may serve as a promising solution to protect WM against blast exposure.
Detection of metallicity correlations in 100 nearby galaxies
Authors: Li Zefeng , Krumholz Mark R , Wisnioski Emily , Mendel J Trevor , Kewley Lisa J , Sánchez Sebastian F , Galbany Lluís
Published: May 2021

In this paper, we analyse the statistics of the 2D gas-phase oxygen abundance distributions of 100 nearby galaxies drawn from the Calar Alto Legacy Integral Field spectroscopy Area survey. After removing the large-scale radial metallicity gradient, we compute the two-point correlation functions of the resulting metallicity fluctuation maps. We detect correlations in the majority of our targets, which we show are significantly in excess of what is expected due to beam-smearing, and are robust against the choice of metallicity diagnostic. We show that the correlation functions are generally well-fit by the predictions of a simple model for stochastic metal injection coupled with diffusion, and from the model we show that, after accounting for the effects of both beam smearing and noise, the galaxies in our sample have characteristic correlation lengths of ∼1 kpc. Correlation lengths increase with both stellar mass and star formation rate, but show no significant variation with Hubble type, barredness, or merging state. We also find no evidence for a theoretically predicted relationship between gas velocity dispersion and correlation length, though this may be due to the small dynamic range in gas velocity dispersion across our sample. Our results suggest that measurements of 2D metallicity correlation functions can be a powerful tool for studying galaxy evolution.
GEPIA2021: integrating multiple deconvolution-based analysis into GEPIA
Authors: Li Chenwei , Tang Zefang , Zhang Wenjie , Ye Zhaochen , Liu Fenglin
Published: May 2021

In 2017, we released GEPIA (Gene Expression Profiling Interactive Analysis) webserver to facilitate the widely used analyses based on the bulk gene expression datasets in the TCGA and the GTEx projects, providing the biologists and clinicians with a handy tool to perform comprehensive and complex data mining tasks. Recently, the deconvolution tools have led to revolutionary trends to resolve bulk RNA datasets at cell type-level resolution, interrogating the characteristics of different cell types in cancer and controlled cohorts became an important strategy to investigate the biological questions. Thus, we present GEPIA2021, a standalone extension of GEPIA, allowing users to perform multiple interactive analysis based on the deconvolution results, including cell type-level proportion comparison, correlation analysis, differential expression, and survival analysis. With GEPIA2021, experimental biologists could easily explore the large TCGA and GTEx datasets and validate their hypotheses in an enhanced resolution. GEPIA2021 is publicly accessible at http://gepia2021.cancer-pku.cn/.
The Austerity of Lone Motherhood: Discrimination Law and Benefit Reform
Authors: Campbell Meghan
Published: May 2021

The austerity-motivated reforms of the UK benefit system have had a devastating and disproportionate impact on vulnerable groups. Lone mothers are challenging these regulations as discriminatory. Their claims raise an under-theorised question: how should courts adjudicate claims for status equality in the realm of fiscal policy? The courts are adopting a fragmented model of equality that artificially divides status and economic inequalities. This approach fails to fully account for the multiple dimensions of disadvantage at stake in these claims. Using a substantive equality framework, this article uncovers the intertwined status and economic inequalities perpetuated by the benefit reforms. It then proceeds to evaluate how the courts’ fragmented approach to equality distorts the justification evaluation. Substantive equality can enrich the justification analysis in a manner that both respects the institutional limits of the court and holds the government to account for discrimination in social benefits.
Zooplankton size spectra and production assessed by two different nets in the subarctic Northeast Pacific
Authors: Kwong Lian E , Pakhomov Evgeny A
Published: May 2021

Normalized biomass size spectra (NBSS) are frequently used to describe pelagic communities. However, the underlying structure of NBSS may lead to varying intercepts and slopes when only a portion of the biomass range is sampled. This may be further perpetuated by the sampling efficiency of different gears/mesh sizes. Spatial and seasonal effects of mesh size on zooplankton NBSS and production were evaluated. Zooplankton were collected during winter, spring and summer (2017–2019) between Vancouver Island and Station Papa (50°N, 145°W) using a 64-μm Working Party 2 (WP-2) net and a 236-μm bongo net and analyzed using a bench-top laser optic particle counter. WP-2 and bongo NBSS overlapped in 11 size classes, for which the WP-2 more effectively sampled smaller size classes and converged with the bongo in larger size classes. Differences in NBSS slopes from the two nets were detected, yet no differences in total production. However, the contribution of individual size classes to total production varied spatially and seasonally. Total production in the coastal region exhibited strong seasonal variability. Notably, summer estimates of production in the coastal region were at least 2-fold higher than transitional and open ocean regions. This study suggests that using one mesh size may underestimate zooplankton NBSS and thus production.
Democracy, Complexity, and Science: Exploring Structural Sources of National Scientific Performance
Authors: Whetsell Travis A , Dimand Ana-Maria , Jonkers Koen , Baas Jeroen , Wagner Caroline S
Published: May 2021

Scholars have long hypothesized that democratic forms of government are more compatible with scientific advancement. However, empirical analysis testing the democracy–science compatibility hypothesis remains underdeveloped. This article explores the effect of democratic governance on scientific performance using panel data on 124 countries between 2007–2017. We find evidence supporting the democracy–science hypothesis. Further, using both internal and external measures of complexity, we estimate the effects of complexity as a moderating factor between the democracy–science connection. The results show differential main effects of economic complexity, globalization, and international collaboration on scientific performance, as well as significant interaction effects that moderate the effect of democracy on scientific performance. The findings show the significance of democratic governance and complex systems in national scientific performance.
019 A Simple, Objective Estimate of Dietary Timing as a Circadian Biomarker
Authors: Hanlon Erin , Nesheiwat Wajdey , Sintetas Stephanie , Van Cauter Eve , Knutson Kristen
Published: May 2021

Introduction

The importance of diet for health has been recognized for centuries, yet, the focus has mostly been on what someone eats. Recently, however, focus has expanded to include when someone eats. Experimental studies that manipulated timing of food intake demonstrated effects on metabolic function. Most population-based studies have had to rely on self-reported methods to assess dietary behavior, including food logs or dietary recall, but self-report is subjective, error-prone, and burdensome. The goal of this analysis was to identify an objective estimate of dietary timing in clock time format. Further, we planned to examine whether sleep “chronotype” and this dietary “chronotype” are correlated.

Methods

We used continuous glucose monitoring (CGM), which involves inserting a small sensor into the back of a participant’s upper arm. It measures interstitial glucose levels every 5 minutes continuously for up to 2 weeks. We had 13 participants wear a CGM device for 2–10 days. We characterized dietary timing by simply identifying the clock time at which glucose levels were the highest. We identified this time point for each day and then calculated the mean clock time for each participant. Participants also wore wrist actigraphy for approximately one week and we calculated mean sleep start, sleep end, and midpoint times. We calculated intervals between highest glucose and sleep timing measures.

Results

The mean time of highest glucose was 16:57 (SD 3:05) and ranged from 11:16 to 22:27. The mean (SD) intervals were 10.4 (2.9) hours for sleep end to highest glucose, 13.5 (2.8) hours for midpoint to highest glucose, and 5.8 (2.8) hours for highest glucose to sleep start. The correlations between highest glucose and sleep timing were .13 (p=.70) for sleep start, .05 (p=.88) for sleep end, and -.19 (p=.55) for midpoint.

Conclusion

There was a wide range in the timing of highest glucose values in this sample, Further, the timing of highest glucose does not correlate with sleep timing, which indicates that these two timing measures are not redundant with one another. The timing of highest glucose from CGM may provide an objective, simple circadian biomarker of dietary behavior.

Support (if any)

P01A1011412-18A1
020 Sleep Quality Affects the Plasma Exosomal MicroRNA Expression Profile in Military Personnel with Traumatic Brain Injury
Authors: Mithani Sara , Leete Jacqueline , Pucci Josephine , Guedes Viivan , Kenney Kimbra , Gill Jessica , Werner J Kent
Published: May 2021

Introduction

Disordered sleep is a critical issue facing the US military due to its negative impact on maintaining force readiness, health, and well-being. Traumatic brain injury (TBI) is highly prevalent among military personnel and commonly co-occurs with disturbed sleep: up to 89% of military service members with TBI report poor sleep quality. Disturbed sleep is a hallmark of post-traumatic stress disorder (PTSD), which often coexists with TBI, with upward of 90% of patients with PTSD reporting some form of sleep disturbance. The pathophysiological mechanisms underlying sleep disturbances in TBI patients remain elusive. Exosomal microRNA (exomiRs), which are implicated in intracellular communication, may provide novel insight into molecular networks related to sleep disturbances in TBI patients.

Methods

ExomiR was extracted from plasma samples of 108 post-9/11 military personnel, and veterans with a history of mild TBI enrolled in a multicenter prospective longitudinal study. ExomiR profiling analysis was conducted using nCounter Human v3 miRNA Expression Panel with 798 microRNA probes. Sleep quality was assessed using the global score on the Pittsburgh Sleep Quality Index (PSQI), and symptoms of PTSD were measured with the PTSD Checklist for DSM-5 (PCL-5). Generalized linear models and Spearman’s correlations were constructed to analyze the relationship between levels of exomiR and global PSQI score.

Results

We found 17 exomiR that were significantly (P < 0.05) associated with sleep quality and 11 exomiR significantly associated with PTSD symptoms. Two exomiR, has-miR-1268a and has-miR-139-5p, were significantly associated with both sleep quality and PTSD symptoms. The top three significant exomiR associated with sleep quality were hsa-miR-1250-5p (r = 0.2295, p = 0.0171), hsa-miR-3615(r = 0.2207, p = 0.0229), and hsa-miR-122-5p(r = 0.2069, p = 0.0132).

Conclusion

Overall, these findings suggest that analysis of exosomal miRNA expression may provide novel insights into the underlying pathobiology of sleep quality in military personnel with mild TBI, independent of PTSD symptoms. Further research is needed to understand the biological underpinnings of poor sleep quality in individuals with TBI and to determine causal links.

Support (if any)

Intramural Research Program at the NINR, Department of Defense, Chronic Effects of Neurotrauma Consortium (CENC) Award W81XWH-13-2-0095 and Department of Veterans Affairs CENC Award I01 CX001135.
030 The sleeping brain switches from frontal-subcortical working memory to hippocampal episodic memory processing during NREM sleep
Authors: Chen Pin-Chun , Niknazar Hamid , Whitehurst Lauren , Mednick Sara
Published: May 2021

Introduction

Working memory (WM) and long-term memory (LTM) serve separate functions. The former is a control process for planning and carrying out behavior that is information-independent, whereas the latter is an information-dependent vast store of knowledge and record of prior events. Both domains benefit from sleep. The overall picture emerging is that NREM sleep supports improvement in WM via strengthening of prefrontal-subcortical control networks, as well as the formation of LTM via thalamocortical sigma activity. Prior research suggests a potential antagonistic relation between the two neural processes during NREM sleep. Yet, how the sleeping brain performs both of these feats remain unknown.

Methods

Thirty-eight adults (age = 20.85 ± 2.97 years, 19 Females) were enrolled. We used a double-blind, placebo-controlled, within-subject design to investigate the role of autonomic and central activity on sleep-dependent LTM and WM improvement. We administered zolpidem, a GABA-A agonist, during PSG-recorded night and tested overnight LTM (word-paired-associates) and WM memory (operation-span) changes. We used effective connectivity to explore the causal information flow between central and autonomic sleep features and tested if the magnitude of this influence predicts the trade-off between overnight LTM and WM improvement.

Results

The intervention selectively suppressed vagal cardiac autonomic activity and increased sleep spindle sigma activity (12-15Hz) during non-rapid eye movement sleep (NREM). Behaviorally, the changes in sigma were associated with increased LTM and decreased WM improvement. Effective connectivity demonstrated a significantly decreased communication from autonomic to central regions with zolpidem compared with placebo, and this decrease in causal influence predicted the behavioral trade-off between LTM and WM.

Conclusion

Our results suggest evidence for a sleep switch that toggles between spindle-dependent and vagal-dependent processes during NREM. This switch supports enhancement of both LTM and WM during sleep via separate mechanisms. These results are consistent with prior studies reporting an antagonistic relation between neuromodulators governing the two systems, thalamocortical GABA and noradrenergic (NE) activity, respectively.

Support (if any):
033 The effect of sleep disturbance on cognition in late-life depression
Authors: Ricciardiello Andrea , Naismith Sharon , D’Rozario Angela , Kumfor Fiona , Wassing Rick
Published: May 2021

Introduction

Late-life depression is the most common psychiatric disorder in older adults and is associated with cognitive deficits, however, the role of sleep disturbance in cognitive deficits is poorly defined. In the current study we aimed to examine sleep macro and micro-architecture differences between those with late-life depression and controls. Secondly, we sought to determine how sleep changes relate to clinical memory and executive function measures in those with late-life depression and controls.

Methods

Using prior clinical data, this retrospective study assessed adults >50 years who had completed an overnight PSG study and comprehensive psychiatric, neuropsychological, and medical assessment. Memory performance was measured using the Weschler Memory Scale logical Memory 1 and 2 components, Rey Auditory Verbal Learning Test (Senior) 30-minute recall and Rey Complex Figure 3-minute recall. Executive function was defined by z scores from Trail Making Test, D-KEFS Stroop Test and Controlled Oral Word Association Test. The sample comprised of 71 depressed participants, defined by a Geriatric Depression Scale score ≥6, and 101 non-depressed participants (GDS <6 and no lifetime history of depression using DSM-IV criteria).

Results

Contrary to our hypothesis no significant macroarchitectural differences were observed between the groups. Less time spent in slow-wave sleep (SWS) was associated with worse delayed memory recall scores in the depression group (z=.342, p=0.008) although this was not seen in the control group. SWS and slow wave activity (SWA) were not related to measures of executive function performance. Depressed participants demonstrated a reduced level of sleep spindles (Dep= 159 ±142.8, con= 213±163, p=.03) although there were no associations with memory outcomes.

Conclusion

Compared to younger adults with depression, macroarchitectural differences in those with late-life depression are not as pronounced, due to a reduction of SWS and SWA power as a function of ageing. The efficiency of SWS hippocampal dependent memory processes in depression may be reduced, therefore, more time spent in SWS is related to better memory performance. This study assessed the density of sleep spindles but not spindle and slow wave oscillation coupling which may be more important for hippocampal dependent memory.

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051 Is Working Memory Associated with Ag- related Emotional Memory Bias?
Authors: Sattari Negin , Whitehurst Lauren , Mednick Sara
Published: May 2021

Introduction

Aging is accompanied by deterioration in both working memory (WM) and long-term memory (LTM), though the reason is not well understood. Sleep may play a role in young adults, but the findings in older adults are not as clear. In addition, older adults show better memory for positive memories, whereas youngers tend to hold on to negative memories. The prefrontal cortex has been implicated in this emotional memory bias. The current study investigated the role of working memory (a prefrontal task) on emotional memory consolidation across sleep and wake in young and older adults.

Methods

In the morning, 93 younger (18–39) and 121 older (60–85) adults took a WM task and encoded neutral or negative word pairs, and gave valence and arousal ratings for each pair. After a wake or polysomnography-recorded sleep condition, memory for the word pairs was tested plus valence and arousal ratings.

Results

Youngers had better overall memory (p<.001), with older adults showing better memory for neutral compared to negative word pairs (p=.04), as well as increased positivity (p=.02), which was correlated with LTM performance (p=.009). In contrast, youngers performed better on the negative word pairs (p=.01), but no change in ratings and no association between emotional reactivity and LTM. Further, WM was positively related to memory in youngers (r=.38, p=.02), but not in older adults. Lastly, no role for sleep likely due to the lack of an immediate test.

Conclusion

we found that the positivity bias in aging in both memory and valence, with increasing positivity associated with better memory. We found a robust relation between WM and LTM in youngers but not older adults. Our findings are consistent with the socioemotional-selectivity theory that posits that aging is associated with a relative suppression of negative information while WM may play a role.

Support (if any):
060 Challenging the current assessment criteria for scoring central sleep apnea at altitude
Authors: Bird Jordan , Chan Jason , Rimke Alexander , Kalker Anne , Chan Garrick , Brutsaert Tom , Sherpa Mingma , Day Trevor
Published: May 2021

Introduction

Sleep disordered breathing comes in two forms: obstructive and central sleep apnea (SA). Obstructive sleep apnea (OSA) is caused by upper airway collapse during sleep, and is associated with increases in morbidity and mortality. Conversely, central sleep apnea (CSA) results from increases in respiratory chemosensitivity to blood gas challenges in the context of high-altitude ascent. CSA increases in severity and apneas shorten in duration with higher ascent and/or time spent at altitude. Although both types of SA are characterized by intermittent periods of apnea and hyperventilation, the underlying mechanisms and phenotypes between OSA and CSA are different. A universal scoring system for the two types of context-dependent SA may lead to errors in quantification. The American Association of Sleep Medicine (AASM) developed assessment criteria for SA, which are universally-utilized for all types of SA to quantify an apnea-hypopnea index (AHI; events/hour), where apneas are scored as cessation of breathing ≥10-sec. We aimed to assess the effect of reducing the apnea-detection threshold (ADT) to <10-sec to quantitatively assess the extent that a shorter ADT affects the scoring of AHI in the context of high-altitude ascent, where CSA is universal.

Methods

We assessed CSA using portable polysomnography (ApneaLink, ResMed) during ascent to 5160m in the Nepal Himalaya over 10 days in 15 healthy participants. Files were archived digitally for later analysis using automated scoring software (ApneaLink Reporting Software, ResMed). We quantified and compared AHI using AASM criteria (i.e., 10-sec ADT) and a shorter 5-sec ADT.

Results

AHI was 3.9±4.1 events/hour at 1045m prior to ascent, with AHI increasing to 37.5±32.8 events/hour (P<0.0001) at 5160m after 10 days of incremental ascent using AASM criteria (i.e., 10-sec ADT). When the ADT was reduced to 5-sec at 5160m, AHI was increased to 61.6±38.1 (+61%; P=0.0002).

Conclusion

This preliminary report suggests that the AASM criterion for scoring apneas, which is broadly applied to OSA at low altitude, may underestimate the assessment and quantification of CSA with ascent to and prolonged stays at high altitude. Development of distinct assessment criteria for OSA and CSA may be warranted.

Support (if any)

Natural Science sand Engineering Research Council of Canada
061 Sleep Hygiene as an Intervention to Lower Blood Pressure
Authors: Vazquez Michael , Yang Huan , Dang Rammy , Haack Monika , Mullington Janet
Published: May 2021

Introduction

Insufficient sleep has been shown to increase the risk of a person developing hypertension. Impaired baroreflex sensitivity (BRS) is one of the known underlying mechanisms involved that is responsible for increasing blood pressure (BP). This project investigates the relationship between sleep, BRS, and BP during Valsalva’s Maneuver (VM).

Methods

Fifty participants (59.8 ± 1.5 years; 31 women) completed 3 overnight in-hospital stays. The first stay (S1) was a baseline control; the second stay (S2) followed a 4-week wait-list control condition; the third stay (S3) followed an 8-week randomly assigned intervention that used sleep hygiene approaches and scheduling to either A) stabilize sleep timing, or B) stabilize and extend the bed period. The study is still ongoing, and we are blind to whether participants were randomized to arm A or B of the study. A linear regression model analyzing the R-R Interval (RRI) and corresponding systolic BP was used to calculate the BRS function and the maximum change in SBP (BPMax) during Early Phase II (EPII) of VM.

Results

There was an increasing BRS trend across the three stays during EPII (p=.051). There was no significant increase between S1 and S2 (p=.876), but BRS significantly increased following 8 weeks of intervention at S3 compared to S1 (p=0.033) and S2 (p=0.037). There was also a significant decrease in BPMax across the three stays during EPII (p<.001). There was no significant decrease in EPII BPMax between S1 and S2 (p=.325), but BPMax significantly decreased in S3 compared to S1 (p<0.001) and S2 (p=0.002).

Conclusion

While we are still blind to condition, both conditions are considered active as they both involve stabilizing the sleep period using sleep hygiene. These preliminary data suggest that stabilization of sleep timing and possibly duration, has a positive impact on BP regulation.

Support (if any)

NIH (R01HL125379 to Dr. Janet Mullington), Harvard Catalyst, Harvard Clinical and Translational Science Center (UL1TR001102).
062 Sex Differences in Slow Wave Sleep Following Evening Binge Alcohol Consumption
Authors: Greenlund Ian , Bigalke Jeremy , Tikkanen Anne , Nicevski Jennifer , Smoot Carl , Carter Jason
Published: May 2021

Introduction

Binge alcohol consumption alters normal sleep architecture, often via increased slow wave sleep (SWS) and decreased rapid eye movement (REM) sleep. Women may be more susceptible to the sedative effects of alcohol during blood alcohol content (BAC) decrease as they report higher subjective sleepiness scores prior to bedtime. The purpose of the present study was to examine changes in SWS between men and women following binge alcohol consumption and determine the relation between BAC change at lights out and subsequent sleep architecture.

Methods

Twenty-three participants (11 men, 12 women) between the ages of 21–45 years were tested twice, once after evening binge alcohol consumption and once after fluid control (randomized, cross-over design). The alcohol dose was based on body weight and sex (1g/kg in men, 0.85g/kg in women) and served as a 4–5 drink equivalent consumed over two hours. Breath alcohol content (BrAC) was monitored in 15-minute increments from first drink consumption to lights out. Overnight polysomnography (PSG) was recorded in each individual and scored by a board-certified sleep physician. Statistical analysis consisted of repeated measures ANOVA and Pearson correlation (p>0.05).

Results

Age (24±4 vs. 26±6 years) and BMI (27±4 vs. 27±4 kg/m2) were similar between men and women. Peak BrAC (0.10±0.02% vs. 0.10±0.02%) and percent change (-19±11% vs. -19±11%) in BrAC from peak to lights out were also similar between the sexes. Peak BrAC was significantly correlated to the percentage of SWS in women (r=-0.71; p=0.01), but not men (r=-0.25; p=0.45). Similarly, the percent change in BrAC from peak to lights out was significantly correlated to the percentage of SWS in women (r=-0.66; p=0.02), but not men (r=-0.40; p=0.22). The SWS and REM latencies were not associated with either peak or lights out BrAC in both men and women.

Conclusion

Peak BrAC, and the rate of BrAC clearance prior to lights out, appear to impact SWS differently in men and women. Specifically, women appear to have more SWS in response to high BrAC than their male counterparts, suggesting a stronger depressor impact with regards to SWS in women.

Support (if any)

National Institutes of Health (AA-024892; U54GM115371; P20GM103474).
068 Morning Cardiovascular Function in Chronic Cannabis Users and Healthy Controls
Authors: Robinson LaTroy , Thosar Saurabh , Stewart Alicia , Clemons Noal , Chess Daniel , Herzig Maya , Gagnon Jacqueline , Ordaz-Johnson Omar , Emens Jonathan , Shea Steven , Bowles Nicole
Published: May 2021

Introduction

In the US cannabis is recreationally legal in 15 states and medically legal in 34 states. Preclinical studies suggest beneficial effects of cannabis on the cardiovascular system (e.g., vasorelaxation). Yet, acute cases of hospitalization after cannabis consumption indicate potential adverse cardiac effects. Vascular endothelial function is a marker of cardiovascular disease and is measured as a change in resting brachial artery diameter (flow-mediated dilation, FMD) during reactive hyperemia. Both resting diameter (positively) and FMD response (negatively) are associated with cardiovascular risk. Resting diameter likely depends on long-term structural changes, and FMD response mostly depends on nitric oxide. Reactive hyperemia is more complex and depends on numerous variables, including adenosine and prostaglandins. FMD is attenuated in the morning when the frequency of adverse cardiovascular events peaks. To begin to understand the effects of chronic cannabis use on the cardiovascular system, in this pilot study, we compared morning measurements of vascular endothelial function, blood pressure, and heart rate between chronic cannabis users and controls while controlling for prior nighttime sleep opportunities.

Methods

Participants, cannabis non-users (n=5) and users (n=4), 44% female, age 25.4 ± 3.6 years - no demographic differences between groups, kept a consistent 2-week sleep schedule at home followed by an 8h sleep opportunity at their habitual time in the laboratory. Upon-wakening, we measured resting blood pressure, heart rate, baseline diameter, hyperemic response, and FMD. Statistical differences between groups were calculated using a two-tailed t-test.

Results

Systolic and diastolic blood pressures (p=0.13 and 0.26 respectively), heart rate (p=0.97), and FMD response (p=0.99) did not differ between groups. However, chronic cannabis users had a significantly higher baseline brachial artery diameter (mean difference: 1.04 mm ± 0.26, p=0.005), and lower hyperemic response (mean difference: -7944 iu/s ± 2538, p=0.02) compared to non-users.

Conclusion

These preliminary findings suggest that chronic cannabis consumption may be associated with adverse structural and functional changes in the vasculature of otherwise healthy young adults. Based on these initial observations, cannabis may act on the cardiovascular system via non-nitric oxide mechanisms. However, it is necessary to increase our sample size to test the robustness of these findings.

Support (if any)

KL2TR002370, AASM
074 Basal Forebrain GABAergic Neurons Promote Arousal by Disinhibiting the Orexin Neurons via Local GABAergic Interneurons
Authors: Cristofolini Michela , De Luca Roberto , Venner Anne , Ferrari Loris , Grace Kevin , Fuller Patrick , Arrigoni Elda
Published: May 2021

Introduction

Optogenetic and chemogenetic studies have shown that activation of basal forebrain (BF) GABAergic neurons rapidly wakes up mice from non-REM (NREM) sleep. These wake-promoting responses have been attributed to BF GABAergic neurons projecting to the cerebral cortex and more specifically to the inhibition of cortical fast-spiking interneurons. Tracing studies have however found that BF GABAergic neurons also densely innervate the lateral hypothalamus (LH) perifornical area, although the role of this pathway in behavioral state control remains mostly unexplored.

Methods

We conducted in vivo and in vitro optogenetic studies. We selectively expressed channelrhodopsin-2 (ChR2) in BF GABAergic neurons by injecting a cre-dependent viral vector encoding for ChR2 into the BF of VGAT-cre mice. We photostimulated the BF GABAergic input to the LH with optical fibers placed into the LH of EEG instrumented mice. For in vitro recordings we expressed ChR2 in BF GABAergic neurons and we fluorescently labeled orexin or LH GABAergic neurons. We recorded in brain slices from identified orexin neurons or GABA neurons while photostimulating the BF GABAergic input.

Results

Optogenetic stimulation of the BF GABAergic fibers in the LH produced rapid arousals from NREM sleep. The same stimulation however did not wake up the mice if they were in REM sleep. We conducted additional studies in brain slices to identify the postsynaptic neurons in the LH targeted by the BF GABAergic input. We found that while optogenetic stimulation of the BF GABAergic input did not produce opto-evoked synaptic responses in the orexin neurons, it produced short-latency opto-evoked inhibitory postsynaptic currents (IPSCs) in LH GABAergic neurons. These opto-evoked IPSCs were GABAA receptor-mediated and were maintained in tetrodotoxin (TTX) indicating monosynaptic connectivity. We have previously found that orexin neurons are inhibited by local LH GABAergic neurons. Our hypothesis is that these local GABAergic interneurons are the target of the BF GABAergic arousal input.

Conclusion

BF GABAergic neurons drive arousal through projections to the LH. We propose that this arousal response is due to the inhibition of local GABAergic interneurons which in turn disinhibit the LH wake-promoting neurons including the orexin neurons.

Support (if any)

NS091126 and HL149630
076 Bright light during wakefulness improves objective and subjective sleep quality: a forced desynchrony study
Authors: Lok Renske , Woelders Tom , Gordijn Marijke , van Koningsveld Minke , Oberman Klaske , Fuhler Sebastiaan , Beersma Domien , Hut Roelof
Published: May 2021

Introduction

Under real life conditions, increased light exposure during wakefulness seems associated with improved sleep quality, quantified as reduced time awake during bed time, increased time spent in non-REM (NREM) sleep or increased power in the EEG delta band (0.5–4 Hz). The causality of these important relationships and their dependency on circadian clock phase and/or time awake has not been studied in depth. To establish causality of light effects during wake time on subsequent sleep, and to disentangle possible circadian and homeostatic interactions, we employed a forced desynchrony (FD) protocol under dim light (6.5 lux) and bright light (1307 lux) during wakefulness.

Methods

The protocol consisted of a fast cycling sleep-wake schedule (13h wakefulness – 5h sleep; 4 cycles), followed by 3h recovery sleep in a within subject cross-over design. Individuals (7 men) were equipped with 10 polysomnography electrodes. Subjective sleep quality was measured immediately after wakening.

Results

Results indicated that circadian variation in delta power was only detected under dim light. Circadian variation in time in rapid eye movement (REM) sleep and wakefulness were uninfluenced by light. Prior light exposure increased accumulation of delta power and time in NREM sleep, while decreasing wakefulness, especially during the circadian wake phase. Subjective sleep quality scores showed that participants were only able to assess light induced improvement of sleep quality correctly when the circadian system promoted wakefulness.

Conclusion

This study presents significant effects of bright light exposure on sleep architecture, leading to sleep pressure related changes in objective sleep quality. At the end of the scheduled sleep phase after increased light exposure, more delta power and NREM sleep were detected, especially when sleep occurred outside the normal sleep phase. Subjective sleep quality scores showed light-induced improvements coinciding with increased delta power and time spend in NREM sleep, suggesting that light during wakefulness may improve subsequent sleep quality. These findings may have important implications for insomnia treatment and clinical applications of light therapy.

Support (if any)

This research was funded by the University of Groningen Campus Fryslân (Grant No. 01110939; co-financed by Philips Drachten and Provincie Fryslân). Additional financial support was obtained from a NWO-STW Program Grant “OnTime” (project 12185).
078 Chronic sleep and circadian disruption differentially affects blood pressure, renal sodium retention, and aldosterone secretion
Authors: McHill Andrew , McMullan Ciaran , Hull Joseph , Wang Wei , Klerman Elizabeth
Published: May 2021

Introduction

Chronic sleep restriction (CSR) and recurrent circadian disruption (RCD; e.g., rotating shiftwork) can increase an individual’s risk of cardiovascular and kidney disease. However, no study has assessed whether CSR and RCD together increase blood pressure (BP) and alter renal function (RF). We tested the hypotheses that the combination of CSR and RCD would increase blood pressure, renal sodium retention, and aldosterone secretion in individuals living for 3 weeks on an imposed non-24-h sleep-wake (SW) schedule (induces RCD) and controlled diet with or without CSR.

Methods

Seventeen (9M) healthy participants (aged 26.1±4.5y [mean±SD]) were scheduled to twenty-four 20-h Forced Desynchrony days and were randomized to either Control (1:2 sleep:wake, 6.67h sleep:13.33h wake; n=8) or CSR (1:3.3 sleep:wake, 4.67h sleep: 5.33h wake; n=9) SW conditions during a 32-day inpatient protocol. BP was measured following ~80–90 min in constant seated posture after scheduled waketime. All urine voids were collected, combined and sampled in 3-6h blocks throughout the study. Samples were assayed for sodium, potassium and aldosterone and analyzed as both excretion rates and total secretion (both per 20h). Data were assigned circadian phase using fitted core body temperature and analyzed using mixed-effects models with circadian phase, aligned/misaligned sleep, or time awake (with associated scheduled activity, sleep/wake, and feeding behaviors) and their interactions as fixed effects.

Results

There was a significant interaction between aligned/misaligned sleep and condition for resting BP (p=0.02), such that systolic BP was ~6% higher following circadian-misaligned sleep in CSR compared to Control (p=0.04). Renal sodium and potassium followed a robust circadian pattern (p<0.0001), with limited influence of time awake. In contrast, the timing of aldosterone excretion was affected by time awake (p<0.05). Total daily renal sodium secretion decreased from beginning to end of the protocol (p=0.03), with no change in sodium consumption and aldosterone secretion (p=0.95).

Conclusion

Under conditions similar to rotating shiftwork, systolic BP increased and sodium, potassium, and aldosterone were differentially influenced by circadian phase and scheduled behaviors. Additionally, renal sodium secretion decreased despite minimal changes in aldosterone secretion, suggesting increased renal aldosterone sensitivity. These findings may provide insight into mechanisms contributing to poor cardiovascular and renal health observed in shiftwork.

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081 Implicit and Explicit Stigma Towards Evening Types
Authors: Kim Kelly , Dietch Jessica , Douglas Megan
Published: May 2021

Introduction

Negative explicit and implicit stigma surrounding mental and physical health conditions are endorsed by people with and without these conditions. Stigma can lead to adverse consequences such as higher levels of distress and isolation. People with insomnia report internalized stigma associated with their insomnia and often delay treatment as a result. Although anecdotal reports of a similar stigma exist for delayed chronotypes, particularly among emerging adults, this effect has not been empirically examined. The present study aims to examine explicit and implicit attitudes about chronotype in a sample of emerging adults.

Methods

Participants were undergraduates (M age=19.9 [SD=1.5], 83.7% female). Demographic, sleep, and circadian questionnaires, including the Morningness-Eveningness Questionnaire to assess chronotype, were collected. Explicit stigma was measured by rating morning and evening types from 0–100 on eight pairs of opposing characteristics (e.g., lazy/motivated) and means were compared with paired samples t-tests using correction for multiple comparisons. Implicit stigma was measured using the Implicit Association Test with attributes associated with “good” and “bad” and targets of “night owl” or “early bird” and the mean score was compared to benchmarks. Regression was conducted to determine whether chronotype predicted implicit or explicit attitudes.

Results

Analyses of explicit attitudes revealed evening types were rated as possessing significantly more of the following characteristics: Lazy (Cohen’s d=0.71), Unhealthy (1.22), Undisciplined (1.19), Immature (0.64), Creative (0.59), and Young (1.20), adjusted ps<.01. Analysis of implicit attitudes revealed a d score of 0.57 (SD=0.47), which indicates a moderate implicit bias of pairing “night owl” with “bad” and “early bird” with “good.” Chronotype was not significantly associated with implicit or explicit attitudes, F(1,47)=0.04, p=.849.

Conclusion

Overall, greater negative explicit and implicit stigma were found for eveningness tendency compared to morningness tendency. Creativity and youthfulness were also rated higher for eveningness. Individual chronotype did not predict implicit or explicit attitudes, suggesting a potential broad societal bias rather than a specific internalized bias. As explicit and implicit stigma often predict discriminatory behavior and lead to negative consequences for the target group, future studies should examine how negative stigma may impact evening types and the behavioral and psychological consequences of stigma.

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085 Effort Exertion and Good Sleep Interactively Increase the Subjective Value of the Future
Authors: Butterworth James , Kelley Nicholas , Boland Elaine , Sedikides Constantine
Published: May 2021

Introduction

The present study examined how habitual variation in sleep quality shapes reward responsivity following effort exertion. Behavioural and neuroscientific theory and research suggest that expending effort leads to compensatory increases in reward responsivity. Converging evidence links the preference for larger-but-delayed rewards to increases in reward sensitivity in psychophysiological, psychopharmacological, and animal studies. Accordingly, we hypothesized that exerting mental effort would increase the preference for larger-but-delayed rewards (i.e., the subjective value of the future) insofar as these preferences reflect elevated reward responsivity. Furthermore, given that sleep shapes perceptions of effort and preferences for larger-but-delayed rewards, we hypothesized that this finding would be moderated by habitual variation in sleep quality, with the strongest effects apparent among participants reporting habitually good sleep.

Methods

To test these hypotheses, we recruited 79 participants to complete a 10-minute effortful (vs. control) writing task followed by a delay discounting task and the Pittsburgh Sleep Quality Index.

Results

As hypothesized, the effortful writing task (vs. control) participants demonstrated a greater preference for larger-but-delayed rewards (vs. smaller-but-immediate rewards). This effect was moderated by sleep quality with those high but not low in sleep quality showing the hypothesized effect.

Conclusion

Ultimately, we found that exerting mental effort increases the subjective value of the future, particularly among participants who habitually report good sleep. These results suggest that good sleep quality helps us contend with the effortful demands of daily life in a way that promotes long-term goal pursuit.

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097 Subjective Sleep Quality is Associated with the Regulation of Positive Emotions
Authors: Powell Suzanna , Bower Joanne , Deutchman Dagny , Palmer Cara
Published: May 2021

Introduction

Sleep disturbances have been associated with emotion regulation difficulties, which in turn predicts the onset and maintenance of mental health disorders. However, research has primarily focused on the regulation of negative emotions. Associations between sleep and positive emotion regulation strategies are unknown. The current research examined relationships between subjective sleep disturbances (Study 1 and Study 2), objective sleep (Study 2), and positive emotion regulation strategies, including strategies that enhance or maintain positive emotions (i.e., savoring) and strategies that reduce positive emotion (i.e., dampening).

Methods

In Study 1, participants (N = 388, ages 18–64 years, 65% female) completed the Pittsburgh Sleep Quality Index and the Responses to Positive Affect questionnaire to assess their positive emotion regulation strategy use, which consists of three subscales (emotion-focused savoring, self-focused savoring, and dampening). Participants in Study 2 (N = 59, ages 18–30 years, 84% female) completed the Pittsburgh Sleep Quality Index, the Responses to Positive Affect questionnaire, and wore an actigraph for one week.

Results

In Study 1, greater subjective sleep disturbances were associated with increased dampening (β = .45, B = .45, SE = .05, 95% C.I. = .35, .55, p <.001), less emotion-focused savoring (β = -.16, B = -.10, SE = .03, 95% C.I. = -.16, -.04, p <.005) and less self-focused savoring (β = -.16, B = -.08, SE = .03, 95% C.I. = -.13, -.03, p < .05). In Study 2, subjective sleep disturbances were associated with greater dampening (β = .31, B = .70, SE = .32, 95% C.I. = .07, 1.34, p < .05), and marginally less self-focused savoring (β = -.28, B = -.82, SE = .42, 95% C.I. = -1.67, .02, p = .05). Actigraphy-measured sleep was unrelated to positive emotion regulation. All models adjusted for adjusted for age and gender.

Conclusion

Subjective sleep disturbances are associated with positive emotion regulation strategies, particularly strategies that dampen positive emotional experiences. These findings complement prior associations among sleep and the dysregulation of negative emotions, and suggest that sleep-related positive emotion dysregulation may be one mechanism by which sleep can lead to the development of emotional disorders.

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