Daytime Activity Research Articles

Actigraphy-based sleep and activity measurements in intensive care unit patients randomized to ramelteon or placebo for delirium prevention

Patients in the ICU often sleep poorly for various reasons, which may predispose to delirium. We previously conducted a clinical trial in which we tested the efficacy of ramelteon, a melatonin-receptor agonist used to treat insomnia, versus placebo, in preventing ICU delirium in patients who underwent elective pulmonary thromboendarterectomy (PTE) surgery. Here we examine sleep, activity, and circadian patterns, measured with actigraphy, to understand changes in these metrics with our intervention and in those with and without delirium. Participants wore wrist actigraphy devices while recovering post-operatively in the ICU. For sleep analysis, we extracted total sleep time and sleep fragmentation metrics over the 22:00 to 06:00 period nightly, and daytime nap duration from the daytime period (0:600 to 22:00) for each participant. For activity analyses, we extracted the following metrics: total daytime activity count (AC), maximum daytime AC, total nighttime AC, and maximum nighttime AC. Next, we performed a nonparametric circadian analysis on ACs over each 24-h day and extracted the following: interdaily stability (IS), intra-daily variability (IV), relative amplitude (RA), and low and high periods of activity (L5 and M10) as well as their start times. These metrics were compared between patients who received ramelteon versus placebo, and between patients who became delirious versus those who did not develop delirium. We additionally made comparisons between groups for daytime and nighttime light levels. No differences in sleep, activity, circadian metrics or light levels were found between drug groups. Delirious patients, when compared to those who were never delirious, had a lower IS (0.35 ± 0.16 vs. 0.47 ± 0.23; P = 0.006). Otherewise, no differences in IV, L5, M10, or RA were found between groups. L5 and M10 activity values increased significantly over the post-extubation for the whole cohort. No differences were found for daytime or nighttime light levels between groups. Overall, ramelteon did not impact sleep or circadian metrics in this cohort. Consistent with clinical experience, delirious patients had less inter-daily stability in their rest-activity rhythms. These data suggest that actigraphy might have value for individual assessment of sleep in the ICU, and for determining and detecting the impact of interventions directed at improving sleep and circadian activity rhythms in the ICU.Trial registration: REGISTERED at CLINICALTRIALS.GOV: NCT02691013. Registered on February 24, 2016 by principal investigator, Dr. Robert L. Owens.

Interaction-feedback network for multi-task daily activity forecasting

The category and occurrence time of daily activity are two basic tasks of daily activity forecasting in a smart home. Multi-task learning has been employed for daily activity forecasting. However, the category and occurrence time of daily activity are weakly correlated to each other, and the loss functions of the two tasks are difficult to achieve at the same time in multi-task learning. In this paper, a daily activity forecasting approach based on an interaction-feedback network is presented. The proposed method combines the multi-head attention mechanism, convolutional neural networks (CNNs), and bidirectional long short-term (Bi-LSTM) memory units to generate a parallel multi-task forecasting model. In addition, a feedback mechanism is introduced to supervise the learning of the two involved tasks. Public datasets are utilized to evaluate the proposed method. Experimental findings show its effectiveness for multi-task daily activity forecasting in terms of precision, recall, F-score, MAE, RMSE, and R2.

Determinants of diurnal variation in lumbar intervertebral discs and paraspinal muscles: A prospective quantitative magnetic resonance imaging study

PurposeTo prospectively investigate the determinants of diurnal variations in lumbar intervertebral discs and paraspinal muscles. Method71 females aged 19 ∼ 31 years were examined by morning-evening T2 mapping/diffusion kurtosis imaging (DKI), with weight and lifestyle information (time in night bed-rest [TIB], bed-napping, activity time, and sitting time) assessed by standardized questionnaires. Diurnal shifts in T2, mean diffusivity and mean kurtosis (T2-DS, MD-DS and MK-DS; morning-value minus evening-value) were evaluated for L4-S1 discs (normal, Pfirrmann grade Ⅰ/Ⅱ; degenerative, III/IV). T2 and T2-DS were assessed for L4/5 multifidus and erector spinalis. ResultsFor normal discs, bed-napping correlated with MD-DS and MK-DS in disc entirety (p = 0.001 and 0.004); increased activity time suggested higher T2-DS in nucleus pulposus (p = 0.004); prolonged sitting time predicted greater T2-DS in disc entirety and posterior inner annulus fibrosus (PI-AF, p ≤ 0.011); decreased TIB and weight suggested lower T2-DS and higher MK-DS in PI-AF (p = 0.001 ∼ 0.035). For degenerative discs, bed-napping predicted lower T2-DS in nucleus pulposus and PI-AF (p = 0.019); increased TIBsuggested higher T2-DS and lower MK-DS in PI-AF (p = 0.006 and 0.034); longer sitting time predicted higher MK-DS in PI-AF (p = 0.020). Paraspinal muscles exhibited diurnal T2 variation (p < 0.001) which did not correlate with lifestyle factors (p > 0.050). ConclusionsLifestyle and weight have causal effects on the diurnal variation of lumbar discs. Bed-rest may correlate with disc hydration and microstructural stability reserves for subsequent daytime activities. Sitting behavior could induce greater dehydration in normal discs and may alleviate diurnal microstructural rearrangement in degenerative discs. T2 mapping and DKI are promising tools to evaluate disc biomechanics in clinics.

Partial COVID-19 closure of a national park reveals negative influence of low-impact recreation on wildlife spatiotemporal ecology

Human presence exerts complex effects on the ecology of species, which has implications for biodiversity persistence in protected areas experiencing increasing human recreation levels. However, the difficulty of separating the effect on species of human presence from other environmental or disturbance gradients remains a challenge. The cessation of human activity that occurred with COVID-19 restrictions provides a ‘natural experiment’ to better understand the influence of human presence on wildlife. Here, we use a COVID-19 closure within a heavily visited and highly protected national park (Glacier National Park, MT, USA) to examine how ‘low-impact’ recreational hiking affects the spatiotemporal ecology of a diverse mammal community. Based on data collected from camera traps when the park was closed and then subsequently open to recreation, we found consistent negative responses to human recreation across most of our assemblage of 24 species, with fewer detections, reduced site use, and decreased daytime activity. Our results suggest that the dual mandates of national parks and protected areas to conserve biodiversity and promote recreation have potential to be in conflict, even for presumably innocuous recreational activities. There is an urgent need to understand the fitness consequences of these spatiotemporal changes to inform management decisions in protected areas.

Physical activity levels associated with insomnia and depressive symptoms in middle-aged and elderly patients with chronic schizophrenia.

Previous evidence suggested that physical activity had beneficial effects on psychopathological symptoms, insomnia, or depressive symptoms in people with schizophrenia. This study investigated the association between physical activity levels and insomnia and depressive symptoms in middle-aged and elderly hospitalized patients with chronic schizophrenia (CS). 179 participants were enrolled. We used the 30-item Positive and Negative Syndrome Scale (PANSS-30) to assess the psychopathological symptoms. We used the Insomnia Severity Index scale (ISI) and 17-item Hamilton Depression Scale (HAMD-17) to evaluate insomnia and depressive symptoms. Daily physical activity time less than 30 min, within 30-60 min, and more than 60 min were defined as physical inactivity, moderate physical activity, and vigorous physical activity, respectively. The Chi-square test, analysis of variance (ANOVA), and Mann-Whitney U-test were applied for categorical, continuous, and non-normal distribution variables, respectively. The Pearson or Spearman's correlation analyses were utilized to examine the association between physical activity levels, ISI total scores, HAMD total scores, and socio-demographic and clinical variables. Finally, socio-demographic variables with a P-value < 0.05 in the comparison between insomnia/depressive group and non-insomnia/depressive group were considered for inclusion in binary logistic regression analysis to determine the relationship between physical activity levels and insomnia or depressive symptoms. The ISI total scores (r = -0.247, P = 0.001) and HAMD total scores (r = -0.312, P < 0.001) were negatively correlated with physical activity levels. Logistic regression analysis revealed that older age, higher depressive factor scores, and lower physical activity level were influential factors of insomnia symptoms in CS patients (P < 0.05). In addition, vigorous physical activity (compared with physical inactivity) and higher negative and depressive factor scores were independently associated with depressive symptoms in CS patients (P < 0.05). Physical activity levels were influential factors in comorbid insomnia and depressive symptoms in CS patients. Given the benefits of physical activity, it should be strengthened as a routine adjunct to clinical treatment or psychiatric care so as to improve the physical and mental health of patients with psychiatric symptoms.

Differences in adherence to using removable cast walker treatment during daytime and nighttime weight-bearing activities in people with diabetes-related foot ulcers.

Patients' adherence to using knee-high offloading treatment is critical to effective healing of diabetes-related foot ulcers (DFUs). Previous studies have found that patients generally have low adherence to using removable knee-high offloading treatments, yet no study has investigated whether their adherence differs during daytime and nighttime. This study aimed to investigate the levels and factors associated with adherence to using knee-high removable cast walker (RCW) treatment during daytime and nighttime weight-bearing activities in people with DFUs. This was a secondary analysis of data collected from a multi-centre cross-sectional study investigating adherence to using knee-high RCWs among 57 participants with DFUs. All participants had multiple socio-demographic, physiological and psychosocial factors collected, before having their adherence to using RCWs during weight-bearing activity monitored over a 1-week period using the dual activity monitor method. Adherence data were categorised into daytime (06:00-18:00) and nighttime (18:00-06:00) periods and calculated separately. Multiple linear regression was used to identify factors associated with daytime and nighttime adherence. Mean adherence to using RCW during weight-bearing activities in people with DFUs was higher during daytime compared with nighttime [39.9% (SD = 18.9) versus 20.4% (SD = 16.7), p < 0.001]. Factors independently associated with lower adherence during daytime were being male, longer diabetes duration, not having peripheral artery disease (PAD), and higher perceived RCW heaviness. Factors associated with lower adherence during nighttime were higher mean daytime steps, not having retinopathy and having dyslipidaemia. Adherence to using RCWs during weight-bearing activities reduced significantly at nighttime compared with daytime among people with DFUs, and this was associated with different factors. Interventions to improve adherence, in research and clinical practice, should incorporate methods to target daytime or nighttime adherence specifically.

COVID-19 lockdown has indirect, non-equivalent effects on activity patterns of Reeves’s Pheasant (Syrmaticus reevesii) and sympatric species

The outbreak of the COVID-19 pandemic has brought massive shifts in human activities through a global blockade, directly affecting wildlife survival. However, the indirect impacts of changes in human activities are often easily overlooked. We conducted surveys of Reeves’s Pheasant (Syrmaticus reevesii) and its sympatric species by camera traps in forest-type nature reserves in three different scenarios: pre-lockdown, lockdown and post-lockdown. An increase in livestock activities observed during the lockdown and post-lockdown period in our study area provided us an opportunity to investigate the indirect impact of the lockdown on wildlife. The pre-lockdown period was used as a baseline to compare any changes in trends of relative abundance index, activity patterns and temporal spacing of targeted species and livestock. During the lockdown period, the relative abundance index of livestock increased by 50% and there was an increase in daytime activity. Reeves's Pheasant showed avoidance responses to almost all sympatric species and livestock in three different periods, and the livestock avoidance level of Reeves's Pheasant during the lockdown period was significantly and positively correlated with the relative abundance index of livestock. Species-specific changes in activity patterns of study species were observed, with reduced daytime activities of Hog Badger and Raccoon Dog during and after the confinement periods. This study highlights the effect of the COVID-19 lockdown on the responses of wildlife by considering the changes in their temporal and spatial use before, during and after lockdown. The knowledge gained on wildlife during reduced human mobility because of the pandemic aids in understanding the effect of human disturbances and developing future conservation strategies in the shared space, to manage both wildlife and livestock.

Тугоухость и деменция – сопряженность развития: неизбежность и возможная обратимость, желаемое и действительное

In people over 65 years of age, hearing disorders occur in 30% of cases. Hearing impairment affects the psychoemotional status of patients, exacerbating the progression of cognitive deficits. One of the variants of frontotemporal dementia (FTD) is pathogenetically caused by intracranial hypotension syndrome (IHS). The incidence of IHS is estimated to be approximately 2–5 cases per 100,000 inhabitants. One of the complications of SVH is dementia with sagging brain syndrome (BSD), clinically similar to FTD. IHS is regularly accompanied by cochleovestibular disorders, among which audiological deviations prevail. To confirm IHS, positional audiometry is of great importance. Unlike typical FTD, for which effective therapy is unknown, BSD treatment results are positive in 81% of cases. The authors of the publication note an improvement in concentration of attention, analytical ability, and daytime activity in their patients after the course of treatment of IHS. For earlier detection, or confirmation, of the mentioned pathology at the diagnostic stage, the authors propose an increase in the number of studies due to audiometric tests.

Night Time Gadget Use and Quality of Sleep among Health Science Students in Bangalore, India

INTRODUCTION: Electronic gadgets have become a necessity for modern life, and unstructured use of these devices can result in sleep disturbances among youth in the digital era. This study correlated patterns of nighttime electronic gadget use and quality of sleep among health science students.METHODS: Cross-sectional research study was conducted among 243 health science students of selected colleges in Bangalore. The subjects comprised students from pharmacy 79 (32.6%), physiotherapy 79 (32.6%) and nursing 84 (34.7%). A self-administered questionnaire was used to collect demographic information on nighttime electronic gadget use. Sleep quality was assessed using Pittsburgh Sleep Quality Index (PSQI). RESULTS: Watching movies (43.6%), communicating (36.1%) and academic use (20.3%) were the most reported purposes of nighttime gadget use among the students. 22.8 % of the participants were using the gadgets for 2-4 hours and 7.5 % of the students used them for more than 5 hours at night. Linear regression analysis revealed that the habit of checking one’s phone at night and staying up late at night had an impact on the daytime activity of students. Subjective sleep quality, sleep latency, sleep duration and sleep efficiency were significantly affected by nighttime gadget use.CONCLUSION: Unrestricted gadget use during nighttime can result in sleep-deprived individuals who may not be able to perform as efficiently. Effective measures should be initiated to structure the use of technologies.

Circadian clock control of tRNA synthetases in Neurospora crassa

Background: In Neurospora crassa, the circadian clock controls rhythmic mRNA translation initiation through regulation of the eIF2α kinase CPC-3 (the homolog of yeast and mammalian GCN2). Active CPC-3 phosphorylates and inactivates eIF2α, leading to higher phosphorylated eIF2α (P-eIF2α) levels and reduced translation initiation during the subjective day. This daytime activation of CPC-3 is driven by its binding to uncharged tRNA, and uncharged tRNA levels peak during the day under control of the circadian clock. The daily rhythm in uncharged tRNA levels could arise from rhythmic amino acid levels or aminoacyl-tRNA synthetase (aaRSs) levels. Methods: To determine if and how the clock potentially controls rhythms in aspartyl-tRNA synthetase (AspRS) and glutaminyl-tRNA synthetase (GlnRS), both observed to be rhythmic in circadian genomic datasets, transcriptional and translational fusions to luciferase were generated. These luciferase reporter fusions were examined in wild type (WT), clock mutant Δfrq, and clock-controlled transcription factor deletion strains. Results: Translational and transcriptional fusions of AspRS and GlnRS to luciferase confirmed that their protein levels are clock-controlled with peak levels at night. Moreover, clock-controlled transcription factors NCU00275 and ADV-1 drive robust rhythmic protein expression of AspRS and GlnRS, respectively. Conclusions: These data support a model whereby coordinate clock control of select aaRSs drives rhythms in uncharged tRNAs, leading to rhythmic CPC-3 activation, and rhythms in translation of specific mRNAs.

Human disturbance compresses the spatiotemporal niche

Human disturbance may fundamentally alter the way that species interact, a prospect that remains poorly understood. We investigated whether anthropogenic landscape modification increases or decreases co-occurrence-a prerequisite for species interactions-within wildlife communities. Using 4 y of data from >2,000 camera traps across a human disturbance gradient in Wisconsin, USA, we considered 74 species pairs (classifying pairs as low, medium, or high antagonism to account for different interaction types) and used the time between successive detections of pairs as a measure of their co-occurrence probability and to define co-occurrence networks. Pairs averaged 6.1 [95% CI: 5.3, 6.8] d between detections in low-disturbance landscapes (e.g., national forests) but 4.1 [3.5, 4.7] d between detections in high-disturbance landscapes, such as those dominated by urbanization or intensive agriculture. Co-occurrence networks showed higher connectance (i.e., a larger proportion of the possible co-occurrences) and greater proportions of low-antagonism pairs in disturbed landscapes. Human-mediated increases in species abundance (possibly via resource subsidies) appeared more important than behavioral mechanisms (e.g., changes in daily activity timing) in driving these patterns of compressed co-occurrence in disturbed landscapes. The spatiotemporal compression of species co-occurrences in disturbed landscapes likely strengthens interactions like competition, predation, and infection unless species can avoid each other at fine spatiotemporal scales. Regardless, human-mediated increases in co-occurrence with-and hence increased exposure to-predators or competitors might elevate stress levels in individual animals, with possible cascading effects across populations, communities, and ecosystems.

240: ASSOCIATIONS BETWEEN ACTIVITY AND COGNITIVE FUNCTION IN OLDER INTENSIVE CARE UNIT SURVIVORS

Introduction: Critically ill older adults are profoundly inactive while in ICU; therefore, activity promotion after ICU discharge is crucial for recovery. Poor cognitive function predicts institutionalization (i.e., discharge to long-term care facility). We calculated a ratio of daytime-to-nighttime activity among older ICU survivors during the early post-ICU transition period. We hypothesized that higher daytime-to-nighttime activity ratios (i.e., proportionally higher activity during daytime hours) would be associated with better cognitive function. Methods: This was a secondary analysis of pooled data from 2 primary studies of older adults (n = 44) who were functionally independent prior to hospitalization, mechanically ventilated while in ICU, and within 24-48 hours post-ICU discharge. Actigraphy recorded daytime activity (mean activity counts/minute, 06:00 AM-21:59 PM) and nighttime activity (mean activity counts/minute, 22:00 PM-05:59 AM). We calculated a daytime-to-nighttime activity ratio by dividing daytime activity by nighttime activity. The NIH Toolbox Dimensional Change Card Sort Test assessed cognitive flexibility (DCCST: fully-corrected T score). Multivariate regression examined the association between the daytime-to-nighttime activity ratio and DCCST scores, adjusting for 3 covariates (age, CAM-S delirium severity score, and NIH Toolbox Grip Strength fully-corrected T score). Results: The mean daytime-to-nighttime activity ratio was 2.10 ± 1.17 (IQR: 1.42). Ratios for 6 (13%) participants were less than 1—these participants were proportionally more active during nighttime hours, rather than daytime hours. Higher ratios were associated with better DCCST scores (β = 0.288, p = .015). Conclusions: Among this cohort of older ICU survivors, the proportion of daytime activity versus nighttime activity was considerably low, indicating severe alterations in the rest/activity and sleep/wake cycles. Higher daytime-to-nighttime activity ratios were associated with better executive function scores, suggesting that daytime inactivity and sleepiness may be an indicator of worse cognitive outcomes. Assessment and promotion of daytime activity and nighttime sleep could identify at-risk older ICU survivors during the early post-ICU transition period.

Post-operative sleep and activity patterns in critically ill children after cardiac surgery

BackgroundChildren with congenital heart disease often have medical and surgical complexity and prolonged and complicated recovery time in the intensive care unit. Limited data are published describing sleep duration, timing, and quality in this population. ObjectivesThis study was performed to describe sleep and activity patterns of children with congenital heart disease in the immediate post-operative period. MethodsThis was a secondary analysis of an observational trial of children (0-18 years) who underwent cardiac surgery and had accelerometer data. The primary outcome was the daytime activity ratio estimate (DARE), defined as the proportion of activity that occurred during the daytime hours. Secondary outcomes were sleep quality, including sleep fragmentation index and sleep duration. ResultsIn total, 130 subjects with 794 hospital days of sleep data were included. Median age was 2.9 years (IQR 0.6-9.9). 83 (63.8%) were males, and 51 (39%) had cyanotic lesions. 35 subjects (26.9%) underwent single ventricle repairs. Average nighttime activity levels were higher than normal in all subjects with an average DARE of 61.1% (±5), normal 75%. Variables independently associated with DARE were total daily sleep time (p=0.005) and total benzodiazepine dose in mcg/kg (p=0.006). Almost half of the subjects had inadequate total sleep time (60, 46%). There was a significant decrease in total sleep time and proportion of subjects with adequate sleep duration in the lower age categories. For every year increase in age, the odds of adequate sleep increased by 27%, p<0.001. ConclusionChildren post cardiac surgery have higher than normal levels of nighttime activity and almost half do not meet the recommended daily hours of sleep. Infants under 1 year of age may be at a higher risk of inadequate sleep. Exposure to benzodiazepines may also affect the balance between daytime and nighttime sleep patterns after cardiac surgery.

Activity patterns throughout the annual cycle in a long-distance migratory songbird, the red-backed shrike Lanius collurio

BackgroundLong-distance migratory birds undergo complex annual cycles during which they must adjust their behaviour according to the needs and conditions encountered throughout the year. Yet, variation in activity throughout the entire annual cycle has rarely been studied in wild migratory birds.MethodsWe used multisensor data loggers to evaluate the patterns of activity throughout the complete annual cycle of a long-distance migratory bird, the red-backed shrike Lanius collurio. Accelerometer data was used to identify life-history stages and to estimate levels of activity during various phases of the annual cycle. In this study, we analysed the variation in daytime activity along the annual cycle and between migratory and non-migratory days.ResultsThe birds’ daytime activity varied throughout the annual cycle while night-time activity was almost exclusively restricted to migratory flights. The highest daytime activity levels were observed during the breeding season, while it remained low during autumn migration and the winter period. Daytime activity differed between sexes during the breeding period, when the males showed the highest level in activity. During migratory periods, both sexes exhibited a higher daytime activity in spring compared to autumn migration, being particularly high in the final migratory leg towards the breeding ground. The birds showed a lower daytime activity on migratory days (days when a migratory flight took place during the succeeding night) than on non-migratory days during both migratory seasons.ConclusionsActivity measured during daytime results from a combination of several behaviours, and a high daytime activity during spring migration and the breeding period is possibly reflecting particularly energy-demanding periods in the annual cycle of migratory birds. The use of multisensor data loggers to track annual activity provides us with a full annual perspective on variation in activity in long-distance migratory species, an essential approach for understanding possible critical life-history stages and migration ecology.

Actigraphy and sleep‐monitoring devices to help differentiate dementia with Lewy bodies from Alzheimer’s disease

AbstractBackgroundDementia with Lewy bodies (DLB) is difficult to differentiate from Alzheimer’s disease (AD) in clinical settings. Actigraphy and sleep‐monitoring devices have the potential to generate data in between clinic visits to help improve the identification of DLB.ObjectiveWe will assess the feasibility of measuring activity and sleep, including day/night reversal, in participants with DLB (n=5) and AD (n=4).MethodParticipants were asked to wear actigraphy devices on their wrists for 2 weeks and sleep‐monitoring EEG devices on their foreheads for 2 nights. Actigraphy recording errors were detected by logging instances in which the majority of acceleration values approached the maximum; reliability was evaluated by logging 15‐minute actigraphy and 1‐hour sleep‐monitoring periods with at least some valid data. Actigraphy tolerability was evaluated by examining non‐wear times. Ten variables were selected to evaluate day/night reversal.ResultAveraged across all individuals, only 0.02% of the 15‐minute actigraphy recording periods had a recording error, 100% of the 15‐minute periods had at least some valid data, and only 0.15% of the periods reflected non‐wear times. For the sleep‐monitoring device, an average of 78% of each nightly recording were considered valid. Of the ten day/night reversal variables, two sleep‐monitor variables showed the strongest differences between DLB and AD: sleep efficiency (mean [SD] = 0.56 [0.19] for DLB; mean [SD] = 0.74 [0.11] for AD; see Fig. 1) and percent sleep in REM (mean [SD] = 6.83 [9.16] for DLB; mean [SD] = 18.3 [4.13] for AD; see Fig. 2). The ratio of nighttime to daytime activity as measured by actigraphy (mean [SD] = 0.37 [0.18] for DLB; mean [SD] = 0.38 [0.08] for AD) showed strong differences in the variability of measurements between AD and DLB (see Fig. 3).ConclusionThese findings suggest that actigraphy and sleep‐monitoring devices are tolerable for participants with dementia and that the devices can reliably collect valid activity and sleep data in between clinic visits. Sleep efficiency and percentage REM sleep were lower in participants with DLB than in participants with AD. Larger studies should further explore the promise of actigraphy and sleep‐monitoring devices for differentiating DLB and AD.

Inverse forgetting in unconscious episodic memory

Forming memories of experienced episodes calls upon the episodic memory system. Episodic encoding may proceed with and without awareness of episodes. While up to 60% of consciously encoded episodes are forgotten after 10 h, the fate of unconsciously encoded episodes is unknown. Here we track over 10 h, which are filled with sleep or daytime activities, the retention of unconsciously and consciously experienced episodes. The episodes were displayed in cartoon clips that were presented weakly and strongly masked for conscious and unconscious encoding, respectively. Clip retention was tested for distinct clips directly after encoding, 3 min and 10 h after encoding using a forced-choice test that demands deliberate responses in both consciousness conditions. When encoding was conscious, retrieval accuracy decreased by 25% from 3 min to 10 h, irrespective of sleep or wakefulness. When encoding was unconscious, retrieval accuracy increased from 3 min to 10 h and depended on sleep. Hence, opposite to the classic forgetting curve, unconsciously acquired episodic memories strengthen over time and hinge on sleep on the day of learning to gain influence over human behavior.

Anthropogenic risk increases night‐time activities and associations in African elephants (Loxodonta africana) in the Ruaha‐Rungwa ecosystem, Tanzania

AbstractElephants face diverse threats from human activities and use temporal and social strategies to reduce human‐induced mortality risk. We used data from camera trap surveys in 2018–2019 (n = 1625 independent detection events from 11,751 sampling days) to investigate elephant responses to anthropogenic risk in the Ruaha‐Rungwa ecosystem, Tanzania. The study was conducted in one low‐risk and three high‐risk sites using 26–40 paired camera trap stations per site. Risk influenced the active periods, use of roads and water sources, social associations and behaviour of elephants. Elephants demonstrated significantly more night‐time and reduced daytime activity in the high‐risk sites relative to the low‐risk site. This higher night‐time activity in the high‐risk sites was observed for both males and females, though it was more pronounced for cow–calf groups than lone males. Foraging events and use of water sources were more frequent at night in the high‐risk sites. Elephants used roads as movement routes in the low‐risk site but avoided roads in the high‐risk sites. Males were significantly more likely to associate with other males and cow–calf groups in the high‐risk sites. Fewer occurrences of relaxed behaviours were observed in the high‐risk sites compared to the low‐risk site. We discuss the potential implications of our findings for elephant survival and reproduction.

Preterm toddlers have low nighttime sleep quality and high daytime activity

A number of studies have been made on the sleep characteristics of children born preterm in an attempt to develop methods to address the sleep problems commonly observed among such children. However, the reported sleep characteristics from these studies vary depending on the observation methods used, i.e., actigraphy, polysomnography and questionnaire. In the current study, to obtain reliable data on the sleep characteristics of preterm-born children, we investigated the difference in sleep properties between 97 preterm and 97 term toddlers of approximately 1.5 years of age using actigraphy. Actigraphy units were attached to the toddlers’ waists with an adjustable elastic belt for 7 consecutive days, and a child sleep diary was completed by their parents. In the study, we found that preterm toddlers had more nocturnal awakenings and more daytime activity, suggesting that preterm-born children may have a different process of sleep development in their early development.

Setting your clock: associations between timing of objective physical activity and cardiovascular disease risk in the general population.

Little is known about the impact of daily physical activity timing (here referred to as 'chronoactivity') on cardiovascular disease (CVD) risk. We aimed to examined the associations between chronoactivity and multiple CVD outcomes in the UK Biobank. physical activity data were collected in the UK-Biobank through triaxial accelerometer over a 7-day measurement period. We used K-means clustering to create clusters of participants with similar chronoactivity irrespective of the mean daily intensity of the physical activity. Multivariable-adjusted Cox-proportional hazard models were used to estimate hazard ratios (HRs) comparing the different clusters adjusted for age and sex (model 1), and baseline cardiovascular risk factors (model 2). Additional stratified analyses were done by sex, mean activity level, and self-reported sleep chronotype. We included 86 657 individuals (58% female, mean age: 61.6 [SD: 7.8] years, mean BMI: 26.6 [4.5] kg/m2). Over a follow-up period of 6 years, 3707 incident CVD events were reported. Overall, participants with a tendency of late morning physical activity had a lower risk of incident coronary artery disease (HR: 0.84, 95%CI: 0.77, 0.92) and stroke (HR: 0.83, 95%CI: 0.70, 0.98) compared to participants with a midday pattern of physical activity. These effects were more pronounced in women (P-value for interaction = 0.001). We did not find evidence favouring effect modification by total activity level and sleep chronotype. Irrespective of total physical activity, morning physical activity was associated with lower risks of incident cardiovascular diseases, highlighting the potential importance of chronoactivity in CVD prevention.

Dietary ketosis improves circadian dysfunction as well as motor symptoms in the BACHD mouse model of Huntington's disease.

Disturbances in sleep/wake cycles are common among patients with neurodegenerative diseases including Huntington's disease (HD) and represent an appealing target for chrono-nutrition-based interventions. In the present work, we sought to determine whether a low-carbohydrate, high-fat diet would ameliorate the symptoms and delay disease progression in the BACHD mouse model of HD. Adult WT and BACHD male mice were fed a normal or a ketogenic diet (KD) for 3 months. The KD evoked a robust rhythm in serum levels of β-hydroxybutyrate and dramatic changes in the microbiome of male WT and BACHD mice. NanoString analysis revealed transcriptional changes driven by the KD in the striatum of both WT and BACHD mice. Disturbances in sleep/wake cycles have been reported in mouse models of HD and are common among HD patients. Having established that the KD had effects on both the WT and mutant mice, we examined its impact on sleep/wake cycles. KD increased daytime sleep and improved the timing of sleep onset, while other sleep parameters were not altered. In addition, KD improved activity rhythms, including rhythmic power, and reduced inappropriate daytime activity and onset variability. Importantly, KD improved motor performance on the rotarod and challenging beam tests. It is worth emphasizing that HD is a genetically caused disease with no known cure. Life-style changes that not only improve the quality of life but also delay disease progression for HD patients are greatly needed. Our study demonstrates the therapeutic potential of diet-based treatment strategies in a pre-clinical model of HD.