Sleep Bouts Research Articles

Variable and consistent traffic noise negatively affect the sleep behavior of a free-living songbird.

Anthropogenic noise is a ubiquitous disturbance factor, which, owing to the extensive nature of transportation networks, and ability of sound waves to penetrate distances, has wide-reaching impacts on biological communities. Research effort on biological effects of anthropogenic noise is extensive, but has focused on waking behavior, and to our knowledge, no published experimental study exists on how noise affects sleep in free-living animals. Sleep plays vital functions in processes such as cellular repair and memory consolidation. Thus, understanding the potential for noise to disrupt sleep is a critical research objective. Whether different noise regimes exert distinct effects on behavior also remains poorly understood, as does intraspecific variation in noise sensitivity. To address these knowledge gaps, we used a repeated-measures field experiment involving broad-casting traffic noise recordings at great tit (Parus major) nest boxes over a series of consecutive nights. We evaluated whether increasing the temporal variability and amplitude of traffic noise increased deleterious effects on sleep behavior in free-living great tits, and whether individuals differed in the magnitude of responses. We found that traffic noise reduced sleep duration, proportion, and bout length, and induced birds to exit nest boxes earlier in the morning. There was some support for a stronger effect of more variable noise, and relative to lower amplitude noise, higher amplitude noise resulted in less and more fragmented sleep. Effects of noise on sleep duration were stronger in older adults, and substantial, repeatable variation existed in individual responses. We demonstrate for the first time that anthropogenic noise can have strong effects on sleep in free-living animals, which may have cascading effects on waking behavior, physiology and fitness. Results suggest that reducing the amplitude of traffic noise may be an effective mitigation strategy, and that differences in individual sensitivity are important to consider when evaluating effects of noise exposure. CAPSULE: Experimental exposure to temporally variable and consistent traffic noise negatively affected sleep behavior in a free-living songbird.

The feasibility and reliability of actigraphy to monitor sleep in intensive care patients: an observational study

BackgroundSleep amongst intensive care patients is reduced and highly fragmented which may adversely impact on recovery. The current challenge for Intensive Care clinicians is identifying feasible and accurate assessments of sleep that can be widely implemented. The objective of this study was to investigate the feasibility and reliability of a minimally invasive sleep monitoring technique compared to the gold standard, polysomnography, for sleep monitoring.MethodsProspective observational study employing a within subject design in adult patients admitted to an Intensive Care Unit. Sleep monitoring was undertaken amongst minimally sedated patients via concurrent polysomnography and actigraphy monitoring over a 24-h duration to assess agreement between the two methods; total sleep time and wake time.ResultsWe recruited 80 patients who were mechanically ventilated (24%) and non-ventilated (76%) within the intensive care unit. Sleep was found to be highly fragmented, composed of numerous sleep bouts and characterized by abnormal sleep architecture. Actigraphy was found to have a moderate level of overall agreement in identifying sleep and wake states with polysomnography (69.4%; K = 0.386, p < 0.05) in an epoch by epoch analysis, with a moderate level of sensitivity (65.5%) and specificity (76.1%). Monitoring accuracy via actigraphy was improved amongst non-ventilated patients (specificity 83.7%; sensitivity 56.7%). Actigraphy was found to have a moderate correlation with polysomnography reported total sleep time (r = 0.359, p < 0.05) and wakefulness (r = 0.371, p < 0.05). Bland–Altman plots indicated that sleep was underestimated by actigraphy, with wakeful states overestimated.ConclusionsActigraphy was easy and safe to use, provided moderate level of agreement with polysomnography in distinguishing between sleep and wakeful states, and may be a reasonable alternative to measure sleep in intensive care patients.Clinical Trial Registration number ACTRN12615000945527 (Registered 9/9/2015).

Sleep Patterns of Aging Chimpanzees (Pan troglodytes)

Diurnal primates spend around half of their lifetime sleeping or inactive. These nocturnal behaviors are considerably understudied compared to daytime activities. While it is well established that sleep quality diminishes with age in humans, little is known about the effects of advanced age on sleep in our closest primate relatives. We aimed to describe captive chimpanzee (Pan troglodytes) sleep patterns and examine whether individual sleep quality changed over an 11-yr period. We recorded the individual night rooms of 12 chimpanzees for six nights using infrared video cameras and analyzed 72 nights (936 h) of video. To evaluate long-term changes, we compared our data from 2018–2019 with previously published data from 2007–2008 on the same individuals living under the same conditions. We used complete inactivity and a head-down, lying posture as a proxy measurement for sleep. Each night individuals slept a mean of 10.5 (± SD 1.8) h and woke up 15.1 (± 3.6) times. The mean duration of sleep bouts was 45.4 (± 16.8) and the mean duration of awake bouts was 10.2 (± 8.2) min. We found that as chimpanzees aged they experienced significantly more frequent awakenings and shorter sleep bouts (i.e., more fragmented sleep), but nightly sleep duration and the length of awake bouts did not differ significantly between the two study periods. Our results suggest that chimpanzees experience some changes in sleep with age similar to those in humans and other animals.

Regulation of Sleep Behavior by Overexpression of Amyloid Precursor Protein in Drosophila Neurons

Amyloid precursor protein (APP) can generate neurotoxic β-amyloid 42 (Aβ42) by proteolytic process, which plays a crucial role in the pathogenesis of Alzheimer’s disease (AD). Individuals with mild to moderate AD exhibit sleep disturbance, even before the onset of AD. The purpose of this study is to verify the effect of APP on sleep behavior by using an APP overexpressing Drosophila AD model. APP-overexpressed flies were grouped by age, and their sleep amounts were monitored. Our results demonstrated that APP overexpression had no impacts on sleep amounts in young (4–7 days after eclosion, 4–7AE) flies. However, APP overexpression contributed to lower day and total sleep amounts in the middle-aged (11–14AE) flies. Moreover, old-aged (40AE) flies with overexpressing APP exhibited increased number of sleep bouts and decreased sleep time, indicating sleep fragmentation in these flies. Our results indicated that overexpression of APP in neurons has distinct effects on sleep behavior at different ages, but the specific mechanisms underlying the sleep regulation by APP are needed for further study. In addition, our data also suggest that sleep disturbance in AD animals can be caused by APP expression alterations, which provide a potential treating target for sleep intervention and therapy for AD patients.

Comparing Objective and Subjective Measures of Sleep Loss with Balance Performance in Farmers.

HIGHLIGHTS The farming population is at risk of injury due to sleep deprivation. Loss of sleep during previous night affects balance performance in farmers. Objective measures of sleep are more reliable than subjective measures for predicting balance performance. ABSTRACT. This study aimed to investigate the ability of both subjective and objective sleep measures to predict balance difficulty in agricultural workers. Seven male farmers from rural Nebraska were analyzed for static balance performance following a bout of sleep. Actiwatches were used to measure objective sleep hours and subjective questionnaires, including the Epworth Sleepiness Scale and the Pittsburgh Sleep Quality Index, were used to measure subjective hours of sleep and sleep quality. The participants were observed for 12 sessions, with six in planting season and six in harvest season. Static balance testing consisted of measuring the area, total displacement, and maximum range in the anteroposterior and mediolateral directions of the individual's center of pressure with Tekscan pressure mats. Overall, it was found that objective measures had a higher correlation with the magnitude of balance deviations than subjective measures.

Sleep-Wake Dynamics Pre- and Post-Exposure to Chronic Social Stress

An analytical approach combining the statistical distributions of the sleep-wake bouts and the Markov Transition Matrix is used to explain the under-examined association between the microarchitecture of the sleep-wake cycle and susceptibility to chronic social stress in C57BL/6J mice. We separated the sleep-wake transitions into distinct sleep-wake sequences, NREM⟷Wake and NREM→REM→Wake, which are controlled by independent neural circuits. Our findings imply greater pull towards the wake leading to early termination and fragmentation of the sleep bouts in the light in both sleep-wake sequences pre- and post-stress. Moreover, the stability of NREM in the NREM⟷Wake transition was lower and the probability of transitioning to wake was higher in susceptible relative to resilient or stress-naive mice pre- and post-stress. Our findings help elucidate the mechanistic interplay between sleep and mood by suggesting the potential neural underpinnings of sleep disturbances responsible the aberrant transitions of sleep-wake bouts exhibited by the stress-susceptible phenotype. Funding Information: This study was supported in part by grants from: (NYUAD Annual Research Budget, Brain and Behavior Research Foundation (NARSAD), NYUAD Research Enhancement Fund, NYU Research Enhancement Fund, Al Jalila Research Foundation: DC) and L’OREAL-UNESCO “For Women in Science (FWIS)” Middle East Fellowship (BR). Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: All experiments performed were approved by the NYUAD Animal Care and Use Committee, and all experimental protocols were conducted according to the National Institute of Health Guide for Care and Use of Laboratory Animals (IACUC Protocol: 150005A2).

Multi-parameter Behavioral Phenotyping of the MPP+ Model of Parkinson's Disease in Zebrafish.

Parkinson’s disease (PD) has been modeled in several animal species using the neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its oxidized product 1-methyl-4-phenylpyridinium (MPP+). MPP+ selectively kills dopaminergic neurons in pars compacta of the substantia nigra, inducing parkinsonian symptoms in animals. Typically, neurotoxicity models of PD in zebrafish assess acute drug effects on locomotion. In the present study, we examined the lasting effects of MPP+ exposure and drug treatment in zebrafish larvae. Larvae were incubated in 500 μM MPP+, from 1 to 5 days post fertilization (dpf), followed by 24 h drug-free acclimation. At 6 dpf, the behavior was analyzed for locomotion, thigmotaxis, and sleep. Next, in separate assays we assessed the drug effects of brain injected glial cell-derived neurotrophic factor (GDNF) and 4-phenylbutyrate (PBA), co-incubated with MPP+. We show that MPP+ exposure consistently reduces swim distance, movement frequency, and cumulative time of movement; thus mimicking a parkinsonian phenotype of reduced movement. In contrast, MPP+ exposed larvae demonstrate reduced anxiety-like behavior and exhibit a sleep phenotype inconsistent with human PD: the larvae display longer sleep bouts, less sleep fragmentation, and more sleep. Previously reported rescuing effects of PBA were not replicated in this study. Moreover, whereas GDNF attenuated the sleep phenotype induced by MPP+, PBA augmented it. The current data suggest that MPP+ exposure generates a multifaceted phenotype in zebrafish and highlights that analyzing a narrow window of data can reveal effects that may be inconsistent with longer multi-parameter approaches. It further indicates that the model generally captures motor symptoms more faithfully than non-motor symptoms.

Pharmacotherapies for sleep disturbances in dementia.

Abstract available in English Español فارسی Français 한국어 Português ภาษาไทย 简体中文

Role of Napping for Learning across the Lifespan.

Napping is a common behavior across age groups. While studies have shown a benefit of overnight sleep on memory consolidation, given differences in nap frequency, composition, and intent, it is important to consider whether naps serve a memory function across development and aging. We review studies of the role of naps in declarative, emotional, and motor procedural memory consolidation across age groups. Recent findings in both developmental and aging populations find that naps benefit learning of many tasks but may require additional learning or sleep bouts compared to young adult populations. These studies have also identified variations in nap physiology based on the purpose of the nap, timing of the nap, or age. These studies lend to our understanding of the function of sleep, and the potential for naps as an intervention for those with reduced nighttime sleep or learning impairments.

A Focal Inactivation and Computational Study of Ventrolateral Periaqueductal Gray and Deep Mesencephalic Reticular Nucleus Involvement in Sleep State Switching and Bistability.

Neurons of the ventrolateral periaqueductal gray (vlPAG) and adjacent deep mesencephalic reticular nucleus (DpMe) are implicated in the control of sleep-wake state and are hypothesized components of a flip-flop circuit that maintains sleep bistability by preventing the overexpression of non-rapid eye movement (NREM)/REM sleep intermediary states (NRt). To determine the contribution of vlPAG/DpMe neurons in maintaining sleep bistability we combined computer simulations of flip-flop circuitry with focal inactivation of vlPAG/DpMe neurons by microdialysis delivery of the GABAA receptor agonist muscimol in freely behaving male rats (n = 25) instrumented for electroencephalographic and electromyographic recording. REM sleep was enhanced by muscimol at the vlPAG/DpMe, consistent with previous studies; however, our analyses of NRt dynamics in vivo and those produced by flop-flop circuit simulations show that current thinking is too narrowly focused on the contribution of REM sleep-inactive populations toward vlPAG/DpMe involvement in REM sleep control. We found that much of the muscimol-mediated increase in REM sleep was more appropriately classified as NRt. This loss of sleep bistability was accompanied by fragmentation of REM sleep, as evidenced by an increased number of short REM sleep bouts. REM sleep fragmentation stemmed from an increased number and duration of NRt bouts originating in REM sleep. By contrast, NREM sleep bouts were not likewise fragmented by vlPAG/DpMe inactivation. In flip-flop circuit simulations, these changes could not be replicated through inhibition of the REM sleep-inactive population alone. Instead, combined suppression of REM sleep active and inactive vlPAG/DpMe subpopulations was required to replicate the changes in NRt dynamics.

Objectively measured sleep fragmentation is associated with incident delirium in older hospitalized patients: Analysis of data collected from an randomized controlled trial.

Delirium may lead to poor outcomes in hospitalized older adults, and sleep deprivation may contribute to its pathogenesis. Thus, we sought to measure sleep duration and fragmentation using wrist-worn actigraphy in older, hospitalized patients with and without delirium, and to determine if actigraphy-based parameters could be used to predict delirium prior to clinical recognition. We conducted a secondary analysis of data from a recent, randomized clinical trial aimed at preventing inpatient delirium. Participants (n=70) were aged≥65 years admitted to an internal medicine service. Delirium was defined by the Confusion Assessment Method, or altered mental status identified by a clinician. Sleep measurements were actigraphy-based, and included total sleep time, median sleep bout duration and other measures of sleep fragmentation. We found that total sleep duration was similar between patients with (n=17) and without (n=53) delirium (mean 384.9±SD 162.7 versus mean 456.6±SD 135.8min; p=.081). Mean sleep bout times were shorter in delirious versus never-delirious patients (median 6.1 [interquartile range 4.3-8.9] versus 7.9 [interquartile range 5.7-11.3] min, p=.048). Patients with delirium had more short sleep bouts (< 10min) and fewer longer sleep bouts (> 30min) compared with those without delirium. Increased sleep fragmentation was present prior to the clinical recognition of delirium. Overall, delirium was associated with increased sleep fragmentation detected by actigraphy, and sleep fragmentation might be useful as a biomarker for delirium prediction in the future.

Social and environmental impacts on sleep in captive Asian elephants (Elephas maximus).

Modern zoos strive to improve standards of animal management, husbandry and welfare of their animals as part of a continual evaluation process. Elephants (Elephantidae) have received particular attention in recent years due to the challenge of providing environments which promote natural behavior and opportunities for social interaction. A number of measures have been proposed to measure wellbeing, with sleep quality increasingly being used. Sleep is a vital aspect of life for cell replenishment as well as optimal development of young. Sleep deprivation can lead to immunosuppression and illness; therefore animal managers have a responsibility to ensure they reduce the potential for disturbance through noise, light, or other environmental factors. The social environment also plays an essential role in wellbeing, particularly for species that live in multi-generational family units. In this study the nocturnal behavior of a multi-generational captive herd was observed to determine impacts of husbandry changes on sleep duration and bout length (measured as recumbent rest). As expected, average total duration of sleep was higher in younger elephants and rates were comparable to those reported in other studies of Asian elephants. Overnight access to an outdoor paddock in warmer weather increased overall average bout length of sleep in the herd. Average total duration of sleep also increased for the herd following the movement of an unrelated adult female who had previously shown weak bonds with other herd members. This indicates that social compatibility is a vital component of elephant welfare, impacting not only behavioral interactions but sleep quality and duration.

Association of CSF orexin-A levels and nocturnal sleep stability in patients with hypersomnolence.

To evaluate the associations between CSF orexin-A (ORX) levels and markers of nocturnal sleep stability, assessed by polysomnography. Nocturnal polysomnography data and ORX levels of 300 drug-free participants (55% men, 29.9±15.5 years, ORX level 155.1±153.7 pg/mL) with hypersomnolence were collected. Several markers of nocturnal sleep stability were analyzed: sleep and wake bouts and sleep/wake transitions. Groups were categorized according to ORX levels, in 2 categories (deficient ≤110; >110), in tertiles (≤26, 26-254, >254), and compared using logistic regression models. Results were adjusted for age, sex, and body mass index. We found higher number of wake bouts (43 vs 25, p < 0.0001), sleep bouts (43 vs 25.5, p < 0.0001), and index of sleep bouts/hour of sleep time, but lower index of wake bouts/hour of wake time (41.4 vs 50.6, p < 0.0001), in patients with ORX deficiency. The percentage of wake bouts <30 seconds was lower (51.3% vs 60.8%, p < 0.001) and of wake bouts ≥1 minutes 30 seconds higher (7.7% vs 6.7%, p = 0.02) when ORX deficient. The percentage of sleep bouts ≤14 minutes was higher (2-5 minutes: 23.7% vs 16.1%, p < 0.0001), and of long sleep bouts lower (>32 minutes 30 seconds: 7.3% vs 18.3%, p < 0.0001), when ORX deficient. These findings were confirmed when groups were categorized according to ORX tertiles, with a dose-response effect of ORX levels in post hoc comparisons, and in adjusted models. This study shows an association between ORX levels and nocturnal sleep stabilization in patients with hypersomnolence. Sleep and wake bouts are reliable markers of nighttime sleep stability that correlate with CSF ORX levels in a dose-dependent manner.

Use of actigraphy and sleep diaries to assess sleep and academic performance in pharmacy students

IntroductionSleep parameters have been shown to correlate with academic performance. Current studies assessing sleep in doctor of pharmacy (PharmD) students rely on self-reported sleep parameters and academic performance. The objectives of this study were to describe and compare sleep parameters in pharmacy students using actigraphy and sleep diaries and to assess the correlation of sleep parameters with academic performance. MethodsThis prospective cohort study with convenience sampling assessed sleep parameters in pharmacy students. Thirty-five students completing the second year of a PharmD program participated in the study. Participants wore actigraph watches and maintained sleep diaries for seven consecutive days during the spring and fall semesters, while classes were in session, except for one week prior to exams and the week of exams. Academic performance was tracked during fall and spring semesters. ResultsActigraphy and sleep diaries showed significant differences in sleep latency (SL), actual sleep time (AST), wake bouts, and sleep efficiency (SE). Actigraphy results indicated that the participants fell asleep faster (SL), slept a shorter duration (AST), had more wake bouts, and lower SE than results reported in the sleep diaries. SE and SL from the sleep diaries positively correlated with the fall semester pharmaceutical sciences course and overall spring semester academic performance. Actigraphy recorded AST correlated with performance in both semesters' clinical sciences courses. ConclusionsThe results of actigraphy differed from the sleep diaries. More studies are needed to assess differences in detection of sleep parameters using sleep diaries and actigraphs.

Longitudinal changes in EEG power, sleep cycles and behaviour in a tau model of neurodegeneration

BackgroundDisturbed sleep is associated with cognitive decline in neurodegenerative diseases such as Alzheimer’s disease (AD) and frontotemporal dementia (FTD). The progressive sequence of how neurodegeneration affects aspects of sleep architecture in conjunction with behavioural changes is not well understood.MethodsWe investigated changes in sleep architecture, spectral power and circadian rhythmicity in the tet-off rTg4510 mouse overexpressing human P301L tau within the same subjects over time. Doxycycline-induced transgene-suppressed rTg4510 mice, tTa carriers and wild-type mice were used as comparators. Spectral power and sleep stages were measured from within the home cage environment using EEG electrodes. In addition, locomotor activity and performance during a T-maze task were measured.ResultsSpectral power in the delta and theta bands showed a time-dependent decrease in rTg4510 mice compared to all other groups. After the initial changes in spectral power, wake during the dark period increased whereas NREM and number of REM sleep bouts decreased in rTg4510 compared to wild-type mice. Home cage locomotor activity in the dark phase significantly increased in rTg4510 compared to wild-type mice by 40 weeks of age. Peak-to-peak circadian rhythm amplitude and performance in the T-maze was impaired throughout the experiment independent of time. At 46 weeks, rTG4510 mice had significant degeneration in the hippocampus and cortex whereas doxycycline-treated rTG4510 mice were protected. Pathology significantly correlated with sleep and EEG outcomes, in addition to locomotor and cognitive measures.ConclusionsWe show that reduced EEG spectral power precedes reductions in sleep and home cage locomotor activity in a mouse model of tauopathy. The data shows increasing mutant tau changes sleep architecture, EEG properties, behaviour and cognition, which suggest tau-related effects on sleep architecture in patients with neurodegenerative diseases.

Sleep in honey bees is affected by the herbicide glyphosate

Sleep plays an essential role in both neural and energetic homeostasis of animals. Honey bees (Apis mellifera) manifest the sleep state as a reduction in muscle tone and antennal movements, which is susceptible to physical or chemical disturbances. This social insect is one of the most important pollinators in agricultural ecosystems, being exposed to a great variety of agrochemicals, which might affect its sleep behaviour. The intake of glyphosate (GLY), the herbicide most widely used worldwide, impairs learning, gustatory responsiveness and navigation in honey bees. In general, these cognitive abilities are linked with the amount and quality of sleep. Furthermore, it has been reported that animals exposed to sleep disturbances show impairments in both metabolism and memory consolidation. Consequently, we assessed the sleep pattern of bees fed with a sugar solution containing GLY (0, 25, 50 and 100 ng) by quantifying their antennal activity during the scotophase. We found that the ingestion of 50 ng of GLY decreased both antennal activity and sleep bout frequency. This sleep deepening after GLY intake could be explained as a consequence of the regenerative function of sleep and the metabolic stress induced by the herbicide.

0750 Nocturnal Sleep Stability and Cerebrospinal Fluid Orexin-A Levels: Sleep and Wake Bouts

Abstract Introduction The orexin (ORX)/hypocretin system stabilizes sleep-wake regulation by sustaining long periods of wakefulness in humans and animals. We aimed to evaluate the relationships between cerebrospinal fluid (CSF) ORX levels and markers of nocturnal sleep stability assessed by polysomnography (PSG) in humans. Methods Nocturnal PSG data and CSF ORX levels of 300 drug-free subjects (55% men, 29.9±15.5 years old, mean ORX levels 155.1±153.7 pg/mL) with a complaint of hypersomnolence were collected in the National Reference Center for Narcolepsy, France. Several markers of nocturnal sleep stability were analyzed: wake (WB), sleep bouts (SB), and sleep/wake transitions. Groups were categorized according to ORX levels: two categories (≤110, &amp;gt;110 pg/mL, the current established threshold of ORX-deficiency), and tertiles (≤26,]26;254], &amp;gt;254 pg/mL); and were compared using logistic regression models. Results were adjusted for age, gender and body mass index. Results ORX-deficient subjects had more WB, SB, and sleep-wake transitions than the others. The WB duration was longer and the SB duration shorter in ORX-deficient category. The proportion of the shortest WB (30 sec) was lower in the ORX-deficient category whereas the proportion of WB above 1 min 30 sec was higher. The proportion of SB ≤ 14min was higher among ORX-deficient patients, with opposite results for longer SB. Subsequent analyses performed in the population categorized according to tertiles of CSF ORX-A confirmed all these findings, with a strong dose-response effect of ORX levels in post-hoc comparisons. All results remained highly significant in adjusted statistical models. Conclusion This study provides a strong evidence of the direct effect of ORX on nocturnal sleep stabilization in humans. WB and SB are reliable markers of nighttime sleep stability, strongly correlated to CSF ORX-A levels in a dose dependent way. These PSG biomarkers are promising to be applied in clinical and research settings. Support none

0023 Neuropeptidergic Regulation of Drosophila Larval Sleep

Abstract Introduction Sleep during early life is thought to be important for brain development. Indeed, disruptions in sleep during development have long-lasting effects on cognitive functioning. Recently, our lab has developed the LarvaLodge platform for monitoring sleep in developing Drosophila larvae. Using this system we can investigate the neural circuits and signals controlling sleep during early neurodevelopmental periods. Neuropeptides play critical roles in regulating many behaviors in both larvae and adult flies.While several neuropeptides modulate sleep in adult flies, it is not known what role neuropeptides play in controlling larval sleep. Methods To identify peptidergic neurons that regulate 2nd instar larval sleep, we activated neurons labeled by 34 independent Gal4 driver lines corresponding to 25 different neuropeptide genes using the heat-sensitive cation channel, TrpA1. Results Of the 34 Gal4 driver lines, we determined that 2 lines are wake-promoting and 7 lines are sleep-promoting. A subset of these exert effects on sleep without associated changes in wake activity levels. We also observed sleep fragmentation (increase in sleep bout number and decrease in sleep bout length) in 3 lines. Subsequent analysis indicated that manipulation of activity in Diuretic hormone 44 (Dh44)-labeled neurons bidirectionally modulates sleep-wake. Additionally, pan-neuronal knockdown of Dh44 altered sleep duration. Conclusion This work indicates that neuropeptidergic signaling modulates sleep during early development and provides a platform to examine how neuropeptidergic regulation of sleep/wake changes throughout the lifespan. Support NIH T32

0160 Chemogenetic Activation of Hypothalamic Tachykinin 1-Expressing Neurons Reduces Sleep and Increases Resistance to Isoflurane

Abstract Introduction The hypothalamic preoptic area (POA) is a heterogeneous region of the brain, containing intermingled populations of excitatory and inhibitory neurons expressing a wide variety of molecular markers. Of its many important homeostatic roles, the POA modulates arousal including natural states (sleep and wakefulness) as well as drug-induced (anesthetic-induced unconsciousness) states. Although sleep and anesthetic-induced unconsciousness are undoubtedly distinct, multiple lines of evidence demonstrate that shared neuronal circuits regulate both states. Previous work identified a population of sleep-promoting, tachykinin 1-expressing (Tac1) neurons within the POA. Given evidence in the VLPO and SON, we hypothesized that Tac1 POA neurons would be another site of convergence for facilitating entry into both NREM sleep and anesthetic-induced unconsciousness. Methods Sleep and isoflurane sensitivity were assessed in Tac1-Cre mice expressing either a Cre-dependent excitatory hM3Dq DREADD or a control fluorophore in the POA. Sleep was assessed using beam break actigraphy, while isoflurane sensitivity was assessed using video tracking as well as a loss of righting reflex assay to construct dose-response curves. Results Unexpectedly, activation of Tac1 POA neurons with 3mg/kg CNO reduced cumulative sleep time by 55% compared to controls (p&amp;lt;0.0001). Decreased sleep time was due to a 59% reduction in sleep bout duration (p&amp;lt;0.01), as the number of sleep bouts remained unchanged. Activity, measured as distance traveled, also increased by 167% compared to vehicle (p&amp;lt;0.0001). Activation of these neurons also increased resistance to isoflurane on both induction (p&amp;lt;0.0001) and emergence (p&amp;lt;0.0001). Additionally, activation during a continuous steady-state exposure to isoflurane destabilized the unconscious state. Conclusion Our results support the concept that POA Tac1 neurons function as a point of convergence for neural circuits regulating arousal from endogenous and drug-induced states of unconsciousness, while also illustrating the complexity of sleep and wake regulation within the hypothalamus. Support R01-GM088156-06, T32-HL007953

0019 Investigating Novel-Sleep Related Genes in Drosophila Melanogaster: A Follow Up on KOMP2 Identified Genes in Mus Musculus

Abstract Introduction Sleep is well-conserved across phylogeny, yet the function of sleep and its underlying mechanisms are currently poorly understood. Novel-sleep related genes were previously identified by our lab in part of the Knockout Mouse Phenotyping Program (KOMP2). This international effort generated single-gene knockouts on a Mus musculus C57BL6/NJ background and proceeded to gather data on over 200 phenotypes, including five days of baseline sleep and wake parameters. Sleep data was gathered using the non-invasive, high-throughput PiezoSleep System (Signal Solutions, LLC) which uses a piezoelectric film to gather movement data which then can be assigned to be wake or sleep. These data identified 122 novel genes that influence sleep phenotypes such as sleep duration and bout length. Methods Homologous proteins were identified and a subset of these genes are under investigation in Drosophila melanogaster, including myosin heavy chain (Mhc) and spinophillin (Spn). Using both genetic mutants and RNAi knockdowns, the effect of gene reduction on activity profiles and sleep are being analyzed. Sleep and activity data is recorded using DAM2 monitors (TriKinetics Inc.) while being maintained on a 12:12 light:dark cycle. Results Preliminary data analysis show that aberrations in Mhc and Spn impact sleep percentage. Both Mhc and Spn are known to be involved in structure and development of synapses. Spn is involved in the neurexin scaffolding of presynaptic neurons and also help with maintaining these synapses once formed. Synaptic reorganization and regulation is known to take place during sleep, showing a potential connection of these proteins and sleep. Conclusion These genes that show effects on sleep in both D. melanogaster and M. musculus show a conservation of the underlying sleep machinery. Support