Effects of Chronic Sleep Restriction during Early Adolescence on the Adult Pattern of Connectivity of Mouse Secondary Motor Cortex

The COMBO window: A chronic cranial implant for multiscale circuit interrogation in mice

Neuroscientists studying the neural correlates of mouse behavior often lack access to the brain-wide activity patterns elicited during a specific task of interest. Fortunately, large-scale imaging is becoming increasingly accessible thanks to modalities such as Ca2+ imaging and functional ultrasound (fUS). However, these and other techniques often involve challenging cranial window procedures and are difficult to combine with other neuroscience tools. We address this need with an open-source 3D-printable cranial implant-the COMBO (ChrOnic Multimodal imaging and Behavioral Observation) window. The COMBO window enables chronic imaging of large portions of the brain in head-fixed mice while preserving orofacial movements. We validate the COMBO window stability using both brain-wide fUS and multisite two-photon imaging. Moreover, we demonstrate how the COMBO window facilitates the combination of optogenetics, fUS, and electrophysiology in the same animals to study the effects of circuit perturbations at both the brain-wide and single-neuron level. Overall, the COMBO window provides a versatile solution for performing multimodal brain recordings in head-fixed mice.

Developmental alcohol exposure is exhausting: Sleep and the enduring consequences of alcohol exposure during development

Prenatal alcohol exposure is the leading nongenetic cause of human intellectual impairment. The long-term impacts of prenatal alcohol exposure on health and well-being are diverse, including neuropathology leading to behavioral, cognitive, and emotional impairments. Additionally negative effects also occur on the physiological level, such as the endocrine, cardiovascular, and immune systems. Among these diverse impacts is sleep disruption. In this review, we describe how prenatal alcohol exposure affects sleep, and potential mechanisms of those effects. Furthermore, we outline the evidence that sleep disruption across the lifespan may be a mediator of some cognitive and behavioral impacts of developmental alcohol exposure, and thus may represent a promising target for treatment.

Sex-dependent and long-lasting effects of adolescent sleep deprivation on social behaviors in adult mice

Increasing evidence indicates that sleep deprivation (SD) can exert multiple negative effects on neuronal circuits, resulting in memory impairment, depression, and anxiety, among other consequences. The long-term effects of SD during early life on behavioral phenotypes in adulthood are still poorly understood. In this study, we investigated the long-lasting effects of SD in adolescence on social behaviors, including empathic ability and social dominance, and the role of the gut microbiota in these processes, using a series of behavioral paradigms in mice combined with 16S rRNA gene pyrosequencing. Behavioral assay results showed that SD in adolescence significantly reduced the frequency of licking, the total time spent licking, and the time spent sniffing during the emotional contagion test in male mice, effects that were not observed in female mice. These findings indicated that SD in adolescence exerts long-term, negative effects on empathic ability in mice and that this effect is sex-dependent. In contrast, SD in adolescence had no significant effect on locomotor activities, social dominance but decreased social interaction in male mice in adulthood. Meanwhile, 16S rRNA gene pyrosequencing results showed that gut microbial richness and diversity were significantly altered in adult male mice subjected to SD in adolescence. Our data provide direct evidence that SD in youth can induce alterations in empathic ability in adult male mice, which may be associated with changes in the gut microbiota. These findings highlight the long-lasting effects of sleep loss in adolescence on social behaviors in adulthood and the role played by the brain-gut axis.

The mediating role of gaze patterns in the association of child sleep disturbances and core symptoms of autism spectrum disorder

Children with autism spectrum disorder (ASD) are at high risk for sleep disturbances, but the mechanism underlying the association between sleep disturbances and ASD core symptoms is largely unknown. This study examined the relationship between sleep disturbances and ASD core symptoms, and the mediating role of gaze patterns during the facial emotion recognition (FER) task. The study included 57 children with ASD and 59 age- and intelligence-matched typically developing (TD) controls aged 3-7 years. Parents reported their children's sleep disturbances and ASD core symptoms using the Children's Sleep Habits Questionnaire (CSHQ) and Social Communication Questionnaire (SCQ). Children's gaze patterns during the FER task were recorded by an eye tracking method. We found (1) ASD children had more severe sleep disturbances than TD children; (2) ASD children had atypical gaze patterns and poor FER task performance as determined by lower accuracy and longer reaction time; (3) sleep disturbances were significantly associated with ASD core symptoms of social interaction, communication, and restricted, repetitive and stereotyped patterns of behavior; and (4) atypical gaze patterns partially mediated the association between sleep disturbances and ASD core symptoms. These findings suggest the need for more comprehensive clinical interventions and more effective sleep interventions to improve ASD core symptoms. LAY SUMMARY: Sleep disturbances are very common in children with autism spectrum disorder (ASD). The current study found that sleep disturbances were significantly associated with ASD core symptoms, and gaze patterns during facial emotion recognition task could partially mediate this relationship.

Evaluating Sleep Disturbances in Children With Rare Genetic Neurodevelopmental Syndromes

BACKGROUND

Adequate sleep is important for proper neurodevelopment and positive health outcomes. Sleep disturbances are more prevalent in children with genetically determined neurodevelopmental syndromes compared with typically developing counterparts. We characterize sleep behavior in Rett (RTT), Angelman (AS), and Prader-Willi (PWS) syndromes to identify effective approaches for treating sleep problems in these populations. We compared sleep-related symptoms across individuals with these different syndromes with each other, and with typically developing controls.

METHODS

Children were recruited from the Rare Diseases Clinical Research Network consortium registries; unaffected siblings were enrolled as related controls. For each participant, a parent completed multiple sleep questionnaires including Pediatric Sleep Questionnaire (Sleep-Disordered Breathing), Children's Sleep Habits Questionnaire (CSHQ), and Pediatric Daytime Sleepiness Scale.

RESULTS

Sleep data were analyzed from 714 participants, aged two to 18 years. Young children with AS had more reported sleep problems than children with RTT or PWS. Older children with RTT had more reported daytime sleepiness than those with AS or PWS. Finally, all individuals with RTT had more evidence of sleep-disordered breathing when compared with individuals with PWS. Notably, typically developing siblings were also reported to have sleep problems, except for sleep-related breathing disturbances, which were associated with each of the genetic syndromes.

CONCLUSIONS

Individuals with RTT, AS, and PWS frequently experience sleep problems, including sleep-disordered breathing. Screening for sleep problems in individuals with these and other neurogenetic disorders should be included in clinical assessment and managements. These data may also be useful in developing treatment strategies and in clinical trials.

Effects of Severe Sleep Disruption on the Synaptic Ultrastructure of Young Mice

There is molecular, electrophysiological, and ultrastructural evidence that a net increase in synaptic strength occurs in many brain circuits during spontaneous wake (SW) or short sleep deprivation, reflecting ongoing learning. Sleep leads instead to a broad but selective weakening of many forebrain synapses, thus preventing synaptic saturation and decreasing the energy cost of synaptic activity. Whether synaptic potentiation can persist or further increase after long sleep deprivation is unknown. Whether synaptic renormalization can occur during chronic sleep restriction (CSR) is also unknown. Here, we addressed these questions by measuring an established ultrastructural measure of synaptic strength, the axon-spine interface (ASI), in the primary motor cortex (M1) of (1) one-month-old adolescent mice CSR using a paradigm that decreases NREM and REM sleep by two/thirds; (2) in two-week-old mouse pups sleep deprived for 15 h, or allowed afterward to recover for 16 h. Both groups were compared with mice of the same age that were asleep or awake for a few hours (both sexes). The ASI size of CSR mice (n = 3) was comparable to that measured after SW or short sleep deprivation and larger than after sleep (n = 4/group). In pups, the ASI size increased after short sleep loss (n = 3) relative to sleep (n = 4), fell below sleep levels after long sleep deprivation (n = 4), and remained low after recovery (n = 3). Long sleep deprived pups also lost some weight. These results suggest that (1) severe sleep restriction is incompatible with synaptic renormalization; (2) very young mice cannot maintain high synaptic strength during prolonged wake.

Voluntary exercise ameliorates synaptic pruning deficits in sleep-deprived adolescent mice

Adolescence is a critical period for brain development and adequate sleep during this period is essential for physical function and mental health. Emerging evidence has detailed the neurological impacts of sleep insufficiency on adolescents, as was unveiled by our previous study, microglia, one of the crucial contributors to synaptic pruning, is functionally disrupted by lack of sleep. Here, we provided evidence featuring the protective effect and the underlying mechanisms of voluntary exercise (VE) on microglial functions in an adolescent 72 h sleep deprivation (SD) model. We identified that the aberrant hippocampal neuronal activity and impaired short-term memory performance in sleep-deprived mice were prevented by 11 days of VE. VE significantly normalized the SD-induced dendritic spine increment and maintained the microglial phagocytic ability in sleep-deprived mice. Moreover, we found that the amendment of the noradrenergic signal in the central nervous system may explain the preventative effects of VE on the abnormalities of microglial and neuronal functions caused by SD. These data suggested that VE may confer protection to the microglia-mediated synaptic pruning in the sleep-deprived adolescent brains. Therefore, physical exercise could be a beneficial health practice for the adolescents that copes the adverse influence of inevitable sleep insufficiency.

Secondary motor cortex: Broadcasting and biasing animal's decisions through long-range circuits

Medial secondary motor cortex (MOs or M2) constitutes the dorsal aspect of the rodent medial frontal cortex. We previously proposed that the function of MOs is to link antecedent conditions, including sensory stimuli and prior choices, to impending actions. In this review, we focus on the long-range pathways between MOs and other cortical and subcortical regions. We highlight three circuits: (1) connections with visual and auditory cortices that are essential for predictive coding of perceptual inputs; (2) connections with motor cortex and brainstem that are responsible for top-down, context-dependent modulation of movements; (3) connections with retrosplenial cortex, orbitofrontal cortex, and basal ganglia that facilitate reward-based learning. Together, these long-range circuits allow MOs to broadcast choice signals for feedback and to bias decision-making processes.

Regional, Layer, and Cell-Type-Specific Connectivity of the Mouse Default Mode Network

The evolutionarily conserved default mode network (DMN) is a distributed set of brain regions coactivated during resting states that is vulnerable to brain disorders. How disease affects the DMN is unknown, but detailed anatomical descriptions could provide clues. Mice offer an opportunity to investigate structural connectivity of the DMN across spatial scales with cell-type resolution. We co-registered maps from functional magnetic resonance imaging and axonal tracing experiments into the 3D Allen mouse brain reference atlas. We find that the mouse DMN consists of preferentially interconnected cortical regions. As a population, DMN layer 2/3 (L2/3) neurons project almost exclusively to other DMN regions, whereas L5 neurons project in and out of the DMN. In the retrosplenial cortex, a core DMN region, we identify two L5 projection types differentiated by in- or out-DMN targets, laminar position, and gene expression. These results provide a multi-scale description of the anatomical correlates of the mouse DMN.

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Mouse resting-state default mode network anatomy described at high resolution in 3D

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Systematic axon tracing shows cortical DMN regions are preferentially interconnected

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Layer 2/3 DMN neurons project mostly in the DMN; layer 5 neurons project in and out

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Retrosplenial cortex contains distinct types of in- and out-DMN projection neurons

The Ontogenesis of Mammalian Sleep: Form and Function

PURPOSE OF REVIEW

To present an up-to-date review and synthesis of findings about perinatal sleep development and function. I discuss landmark events in sleep ontogenesis, evidence that sleep promotes brain development and plasticity, and experimental considerations in this topic.

RECENT FINDINGS

Mammalian sleep undergoes dramatic changes in expression and regulation during perinatal development. This includes a progressive decrease in rapid-eye-movement (REM) sleep time, corresponding increases in nonREM sleep and wake time, and the appearance of mature sleep regulatory processes (homeostatic and circadian). These developmental events coincide with periods of rapid brain maturation and heightened synaptic plasticity. The latter involve an initial experience-independent phase, when circuit development is guided by spontaneous activity, and later occurring critical periods, when these circuits are shaped by experience.

SUMMARY

These ontogenetic changes suggest important interactions between sleep and brain development. More specifically, sleep may promote developmental programs of synaptogenesis and synaptic pruning and influence the opening and closing of critical periods of brain plasticity.

Understanding the role of sleep and its disturbances in Autism spectrum disorder

BACKGROUND

Several studies have established a positive relationship between sleep difficulties and symptomatology in ASD children. The rationale for this review is to describe and discuss the sleep difficulties, which are one of the significant complications associated with autism spectrum disorder (ASD).

PURPOSE

Many types of sleep disorders have been reported in ASD individuals, but still lack a comprehensive study and in-depth analysis. Despite the contribution of sleep problems to the overall symptoms of ASD, the symptoms of disturbed sleep experienced by many affected patients have only recently started to receive attention from clinicians and family members.

MATERIALS AND METHODS

This narrative overview has been prepared based on searching standard research databases with specific keywords; b. Additional search was made using the bibliographies of the retrieved articles; and c. author's collection of relevant peer-reviewed articles. Once selected, manuscripts are then compared and summarized based on the author's perspective. Results are based on a qualitative rather than a quantitative level.

RESULTS

This article highlights the role of sleep in the brain and neural development of children and emphasizes that the intensity of sleep problems is associated with an increased occurrence of ASD symptoms. It also suggests the significance of treating sleep problems in ASD individuals.

CONCLUSIONS

The review provides broader perspectives and a better understanding of sleep problems in pathophysiology, mechanism, and management with respect to ASD individuals. Finally, the implications for clinical practice and future agendas have also been discussed.

Microglia-mediated synaptic pruning is impaired in sleep-deprived adolescent mice

The detrimental effects of sleep insufficiency have been extensively explored. However, only a few studies have addressed this issue in adolescents. In the present study, we examined and compared the effects of 72 h paradoxical sleep deprivation (SD) on adolescent (5 weeks old) and adult (~12 weeks old) mice. Following 72 h of SD, induced by a modified multiple-platform method, mice were subjected to behavioral, histological and neurochemical examinations. In both adolescent and adult mice, SD adversely affected short-term memory in a novel object recognition test. Compared with normal-sleep controls, sleep-deprived adolescent mice had an increased density of excitatory synapses in the granule cells of the dentate gyrus, but no such pattern was observed in the adult group. The engulfment of postsynaptic components within the microglia after SD was reduced in adolescents but not in adults, suggesting an impaired microglia-mediated synaptic pruning in adolescent SD mice. Possible contributing factors included the decreases in CX3CR1, CD11b and P2Y12, closely associated with the synaptic pruning via microglial phagocytosis. In adult SD mice, microglia-associated inflammatory reactions were noted. In sum, sleep deprivation induces age-dependent microglial reactions in adolescent and adult mice, respectively; yet results in similar defects in short-term recognition memory. Sufficient sleep is indispensable for adolescents and adults.

Developmental pathways towards mood disorders in adult life: Is there a role for sleep disturbances?

INTRODUCTION

Mood disorders are among the most prevalent and serious mental disorders and rank high among to the leading global burdens of disease. The developmental psychopathology framework can offer a life course perspective on them thus providing a basis for early prevention and intervention. Sleep disturbances, are considered risk factors for mood disorders across childhood, adolescence and adulthood. Assuming that sleep disturbances may play a pivotal role in the pathogenesis of mood disorders from a life course point of view, we reviewed the data on developmental pathways towards mood disorders in adult life in relation to sleep disturbances.

METHOD

From February 2017, a systematic search was conducted in PubMed, PsycINFO and Embase electronic databases for literature on developmental pathways to mood disorders in adult life in relation to sleep disturbances and to 1) pre-natal stress, 2) early brain developmental processes, and 3) temperaments, character and attachment style.

RESULTS

Eleven, 54 and 15 articles were respectively selected.

CONCLUSIONS

Experimental and clinical studies revealed that exposure to prenatal/early life stress results in sleep disturbances such as poor sleep and altered circadian regulation phases and may predict or even precipitate mood disorders in adulthood. Chronic sleep disruption may interfere with neuronal plasticity, connectivity and the developing brain thus contributing to the development of mood disorders. In addition sleep and circadian dysregulations have been shown to be related to those temperaments, character and attachment styles which are considered precursors of mood disorders. Sleep and circadian behaviours may serve as early targets regarding mood disorders.

Rhythms of life: circadian disruption and brain disorders across the lifespan

Many processes in the human body - including brain function - are regulated over the 24-hour cycle, and there are strong associations between disrupted circadian rhythms (for example, sleep-wake cycles) and disorders of the CNS. Brain disorders such as autism, depression and Parkinson disease typically develop at certain stages of life, and circadian rhythms are important during each stage of life for the regulation of processes that may influence the development of these disorders. Here, we describe circadian disruptions observed in various brain disorders throughout the human lifespan and highlight emerging evidence suggesting these disruptions affect the brain. Currently, much of the evidence linking brain disorders and circadian dysfunction is correlational, and so whether and what kind of causal relationships might exist are unclear. We therefore identify remaining questions that may direct future research towards a better understanding of the links between circadian disruption and CNS disorders.

Evaluation of behavioral change after adenotonsillectomy for obstructive sleep apnea in children with autism spectrum disorder

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) may affect daily cognitive functioning in children. The aims of our study were two-fold. The first aim was to detect, using the Child Behavior Checklist (CBCL), whether adenotonsillectomy (AT) for the treatment of OSA improved the behavior of children with autism spectrum disorder (ASD). The second aim was to identify characteristics for behavioral improvement following the treatment of OSA in these children with ASD.

METHODS

The behaviors of ASD children aged 5-14 years diagnosed as having OSA (n=30) were evaluated using CBCL before and after AT. CBCL evaluation of ASD children without OSA at two time points with the same interval served as a control (n=24). We statistically examined the two groups. In addition, we conducted a paired t-test to assess changes in CBCL Tscores between the improved group and unchanged/deteriorated group to identify characteristics that may affect behavioral changes following OSA treatment.

RESULTS

After AT, T-scores of the CBCL scales were significantly improved in the OSA group, but no change was observed in the control. A paired t-test revealed that the improved group had significantly higher scores on the CBCL pre-AT than the unchanged/deteriorated group in ASD children with OSA after OSA treatment.

CONCLUSIONS

Behavioral problems were significantly improved following AT in ASD children with OSA. Early detection and treatment of children with OSA is essential to prevent behavioral problems and to support mental development.

The Sleeping Brain

The role of sleep has long baffled scientists, but the latest research is providing new indicators about what it does for both the brain and body. While scientists believe that sleep re-energizes the body's cells, clears waste from the brain, and supports learning and memory, much still needs to be learned about the part it plays in regulating mood, appetite and libido. Source/Shutterstock.

Shorter sleep duration is associated with social impairment and comorbidities in ASD

Sleep disturbance, particularly insomnia, is common in children with autism spectrum disorders (ASD). Furthermore, disturbed sleep affects core symptoms and other related comorbidities. Understanding the causes and consequences of sleep disturbances in children with ASD is an important step toward mitigating these symptoms. To better understand the connection between sleep duration and ASD severity, we analyzed ASD-related symptoms using the Autism Diagnostic Interview-Revised (ADI-R), Autism Diagnostic Observation Schedule (ADOS), IQ scores, and parent reports of the average amount of time slept per night that were available in the medical histories of 2,714 children with ASD in the Simons Simplex Collection (SSC). The mean (SD) sleep duration was 555 minutes. Sleep duration and severity of core ASD symptoms were negatively correlated, and sleep duration and IQ scores were positively correlated. Regression results indicated that more severe social impairment, primarily a failure to develop peer relationships, is the core symptom most strongly associated with short sleep duration. Furthermore, increased severity for numerous maladaptive behaviors assessed on the Child Behavior Checklist, as well as reports of attention deficit disorder, depressive disorder, and obsessive compulsive disorder were associated with short sleep duration. Severity scores for social/communication impairment and restricted and repetitive behaviors (RRB) were increased, and IQ scores were decreased, for children reported to sleep ≤420 minutes per night (lower 5th percentile) compared to children sleeping ≥660 minutes (upper 95th percentile). Our results indicate that reduced amounts of sleep are related to more severe symptoms in children with ASD. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1221-1238. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.