Homeostatic regulation of sleep in the white-crowned sparrow (Zonotrichia leucophrys gambelii)

<p>Abstract</p> <p>Background</p> <p>Sleep is regulated by both a circadian and a homeostatic process. The homeostatic process reflects the duration of prior wakefulness: the longer one stays awake, the longer and/or more intense is subsequent sleep. In mammals, the best marker of the homeostatic sleep drive is slow wave activity (SWA), the electroencephalographic (EEG) power spectrum in the 0.5–4 Hz frequency range during non-rapid eye movement (NREM) sleep. In mammals, NREM sleep SWA is high at sleep onset, when sleep pressure is high, and decreases progressively to reach low levels in late sleep. Moreover, SWA increases further with sleep deprivation, when sleep also becomes less fragmented (the duration of sleep episodes increases, and the number of brief awakenings decreases). Although avian and mammalian sleep share several features, the evidence of a clear homeostatic response to sleep loss has been conflicting in the few avian species studied so far. The aim of the current study was therefore to ascertain whether established markers of sleep homeostasis in mammals are also present in the white-crowned sparrow (<it>Zonotrichia leucophrys gambelii</it>), a migratory songbird of the order Passeriformes. To accomplish this goal, we investigated amount of sleep, sleep time course, and measures of sleep intensity in 6 birds during baseline sleep and during recovery sleep following 6 hours of sleep deprivation.</p> <p>Results</p> <p>Continuous (24 hours) EEG and video recordings were used to measure baseline sleep and recovery sleep following short-term sleep deprivation. Sleep stages were scored visually based on 4-sec epochs. EEG power spectra (0.5–25 Hz) were calculated on consecutive 4-sec epochs. Four vigilance states were reliably distinguished based on behavior, visual inspection of the EEG, and spectral EEG analysis: Wakefulness (W), Drowsiness (D), slow wave sleep (SWS) and rapid-eye movement (REM) sleep. During baseline, SWA during D, SWS, and NREM sleep (defined as D and SWS combined) was highest at the beginning of the major sleep period and declined thereafter. Moreover, peak SWA in both SWS and NREM sleep increased significantly immediately following sleep deprivation relative to baseline.</p> <p>Conclusion</p> <p>As in mammals, sleep deprivation in the white-crowned sparrow increases the intensity of sleep as measured by SWA.</p

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Sleep and Plasticity in Schizophrenia

Schizophrenia is a devastating mental illness with a worldwide prevalence of approximately 1%. Although the clinical features of the disorder were described over one hundred years ago, its neurobiology is still largely elusive despite several decades of research. Schizophrenia is associated with marked sleep disturbances and memory impairment. Above and beyond altered sleep architecture, sleep rhythms including slow waves and spindles are disrupted in schizophrenia. In the healthy brain, these rhythms reflect and participate in plastic processes during sleep. This chapter discusses evidence that schizophrenia patients exhibit dysfunction of sleep-mediated plasticity on a behavioral, cellular, and molecular level and offers suggestions on how the study of sleeping brain activity can shed light on the pathophysiological mechanisms of the disorder

Sleep Related Cognitions in Individuals with Symptoms of Insomnia and Depression

STUDY OBJECTIVES: Depression has been identified as the most common condition comorbid to insomnia, with findings pointing to the possibility that these disorders may be causally related to each other or may share common mechanisms. Some have suggested that comorbid insomnia and depression may have a different clinical course than either condition alone, and may thus require specific treatment procedures. In this report we examined the clinical characteristics of individuals referred to an academic sleep center who report comorbid symptoms of insomnia and depression and those with symptoms of insomnia outside the context of meaningful depression, and we identified differences between these groups with regard to several cognitive-related variables. METHODS: Logistic regression analyses examined whether past week worry, dysfunctional beliefs about sleep, and insomnia symptom-focused rumination predicted group membership. RESULTS: Individuals with comorbid symptoms of insomnia and depression reported more past-week worry, dysfunctional beliefs about sleep, and insomnia symptom-focused rumination, than those with symptoms of insomnia without significant depression symptoms. When including all three cognitive-related variables in our model, those with comorbid symptoms reported more severe insomnia symptom-focused rumination, even when controlling for insomnia and mental health severity, among other relevant covariates. CONCLUSION: The findings contribute to our understanding of the complex nature of comorbid symptoms of insomnia and depression and the specific symptom burden experienced by those with significant depression symptoms in the presence of insomnia. The findings also highlight the need for increased clinical attention to the sleep-focused rumination reported by these patients. CITATION: Levenson JC, Benca RM, Rumble ME. Sleep related cognitions in individuals with symptoms of insomnia and depression. J Clin Sleep Med 2015;11(8):847–854

Sex Differences in the Relationship Between Depressive Symptoms and Actigraphic Assessments of Sleep and Rest-Activity Rhythms in a Population-Based Sample

ObjectiveDepression is often associated with disruptions in sleep and circadian rhythms. We aimed to confirm these relationships via actigraphic assessment in a large, population-based sample and test whether sex moderates these relationships.MethodsA total of 418 participants (age = 35-85 years, mean [standard deviation] = 57.04 [11.47]) completed questionnaires and 1 week of actigraphy, used to calculate sleep and rest-activity statistics including mesor (mean activity level), amplitude (height of rhythm), and acrophase (time of day that rhythm peaks).ResultsDepressive symptoms, assessed via Center for Epidemiologic Studies Depression Scale, were associated with disrupted sleep and rest-activity rhythms. Furthermore, men demonstrated longer sleep onset latency (SOL, B = -13.28, p &lt; .001), longer wake time after sleep onset (B = -6.26, p &lt; .01), lower sleep efficiency (B = 5.91, p &lt; .001), and lower total sleep time (TST, B = 33.16, p &lt; .001) than women. Sex moderated the relationship between depression and SOL, TST, mesor, and amplitude; sex-stratified models revealed that higher depression scores were associated with greater SOL (B = 1.05, p &lt; .001) and less TST (B = -0.87, p &lt; .10) for women with higher depressive symptoms, but lower mesor (B = -1.75, p &lt; .01) and amplitude (B = -1.94, p &lt; .01) for men with higher depressive symptoms.ConclusionsDepressive symptoms were related to disrupted sleep continuity and rest-activity rhythms in this population-based sample; however, these relationships differed by sex. Women with greater depressive symptoms exhibited difficulty with sleep continuity, whereas men with greater depressive symptoms demonstrated disruption throughout the 24-hour rhythm

Wake Up America: National Survey of Patients’ and Physicians’ Views and Attitudes on Insomnia Care

While both patients and physicians consider sleep to be important, sleep health may not receive appropriate consideration during patient visits with health care professionals (HCPs). We completed the first large-scale survey of people with trouble sleeping (PWTS) and physicians who treat insomnia to understand their perspectives and potential discrepancies between them. The Harris Poll conducted online surveys of adult PWTS and HCPs (primary care physicians [PCPs] and psychiatrists) in the United States from September to October 2021. Respondents included 1001 PWTS, 300 PCPs, and 152 psychiatrists. Most HCPs agreed that sleep is critical to good health, yet very few reported routinely conducting full sleep histories on their patients. Approximately 30% of PWTS reported that their PCP never asks about sleep; zero HCPs in this survey reported “never” inquiring. Few HCPs reported being “very satisfied” with current treatment options; 50% of PCPs reported their patients being satisfied. Two-thirds of PWTS did not believe current treatment options adequately improved their sleep. This survey provides evidence that both PWTS and physicians agreed on the importance of sleep, but that treatment is often perceived as ineffective. This survey identifies a need for HCPs to address insomnia management and treatment gaps

Wake Up America: National Survey of Patients’ and Physicians’ Views and Attitudes on Insomnia Care

While both patients and physicians consider sleep to be important, sleep health may not receive appropriate consideration during patient visits with health care professionals (HCPs). We completed the first large-scale survey of people with trouble sleeping (PWTS) and physicians who treat insomnia to understand their perspectives and potential discrepancies between them. The Harris Poll conducted online surveys of adult PWTS and HCPs (primary care physicians [PCPs] and psychiatrists) in the United States from September to October 2021. Respondents included 1001 PWTS, 300 PCPs, and 152 psychiatrists. Most HCPs agreed that sleep is critical to good health, yet very few reported routinely conducting full sleep histories on their patients. Approximately 30% of PWTS reported that their PCP never asks about sleep; zero HCPs in this survey reported "never" inquiring. Few HCPs reported being "very satisfied" with current treatment options; 50% of PCPs reported their patients being satisfied. Two-thirds of PWTS did not believe current treatment options adequately improved their sleep. This survey provides evidence that both PWTS and physicians agreed on the importance of sleep, but that treatment is often perceived as ineffective. This survey identifies a need for HCPs to address insomnia management and treatment gaps