Brain Oscillations and the Importance of Waveform Shape

The blood–brain barrier (BBB) is a large regulatory and exchange interface between the brain and peripheral circulation. We propose that changes of the BBB contribute to many pathophysiological processes in the brain of subjects with chronic sleep restriction (CSR). To achieve CSR that mimics a common pattern of human sleep loss, we quantified a new procedure of sleep disruption in mice by a week of consecutive sleep recording. We then tested the hypothesis that CSR compromises microvascular function. CSR not only diminished endothelial and inducible nitric oxide synthase, endothelin1, and glucose transporter expression in cerebral microvessels of the BBB, but it also decreased 2-deoxy-glucose uptake by the brain. The expression of several tight junction proteins also was decreased, whereas the level of cyclooxygenase-2 increased. This coincided with an increase of paracellular permeability of the BBB to the small tracers sodium fluorescein and biotin. CSR for 6 d was sufficient to impair BBB structure and function, although the increase of paracellular permeability returned to baseline after 24 h of recovery sleep. This merits attention not only in neuroscience research but also in public health policy and clinical practice.

https://www.jneurosci.org/content/jneuro/34/44/14697.full.pdf

Sleep restriction impairs blood-brain barrier function.

The classification of sleep stages is the first and an important step in the quantitative analysis of polysomnographic recordings. Sleep stage scoring relies heavily on visual pattern recognition by a human expert and is time consuming and subjective. Thus, there is a need for automatic classification. In this work we developed machine learning algorithms for sleep classification: random forest (RF) classification based on features and artificial neural networks (ANNs) working both with features and raw data. We tested our methods in healthy subjects and in patients. Most algorithms yielded good results comparable to human interrater agreement. Our study revealed that deep neural networks (DNNs) working with raw data performed better than feature-based methods. We also demonstrated that taking the local temporal structure of sleep into account a priori is important. Our results demonstrate the utility of neural network architectures for the classification of sleep.

/pdf/automatic-human-sleep-stage-scoring-using-deep-neural-ce0fvte01h.pdf

Automatic Human Sleep Stage Scoring Using Deep Neural Networks.

http://www.ece.uvic.ca/~bctill/papers/neurimp/Weiergraeber_etal_2005.pdf

Electrocorticographic and deep intracerebral EEG recording in mice using a telemetry system.

Impaired sleep and enhanced stress hormone secretion are the hallmarks of stress-related disorders, including major depression. The central neuropeptide, corticotropin-releasing hormone (CRH), is a key hormone that regulates humoral and behavioral adaptation to stress. Its prolonged hypersecretion is believed to play a key role in the development and course of depressive symptoms, and is associated with sleep impairment. To investigate the specific effects of central CRH overexpression on sleep, we used conditional mouse mutants that overexpress CRH in the entire central nervous system (CRH-COE-Nes) or only in the forebrain, including limbic structures (CRH-COE-Cam). Compared with wild-type or control mice during baseline, both homozygous CRH-COE-Nes and -Cam mice showed constantly increased rapid eye movement (REM) sleep, whereas slightly suppressed non-REM sleep was detected only in CRH-COE-Nes mice during the light period. In response to 6-h sleep deprivation, elevated levels of REM sleep also became evident in heterozygous CRH-COE-Nes and -Cam mice during recovery, which was reversed by treatment with a CRH receptor type 1 (CRHR1) antagonist in heterozygous and homozygous CRH-COE-Nes mice. The peripheral stress hormone levels were not elevated at baseline, and even after sleep deprivation they were indistinguishable across genotypes. As the stress axis was not altered, sleep changes, in particular enhanced REM sleep, occurring in these models are most likely induced by the forebrain CRH through the activation of CRHR1. CRH hypersecretion in the forebrain seems to drive REM sleep, supporting the notion that enhanced REM sleep may serve as biomarker for clinical conditions associated with enhanced CRH secretion.

/pdf/conditional-corticotropin-releasing-hormone-overexpression-1cwazkuc74.pdf

Conditional corticotropin-releasing hormone overexpression in the mouse forebrain enhances rapid eye movement sleep.

Design and validation of a computer-based sleep-scoring algorithm.

The zebrafish model system is helping researchers improve the health and welfare of people and animals and has become indispensable for advancing biomedical research. As genetic engineering is both resource intensive and time-consuming, sharing successfully developed genetically modified zebrafish lines throughout the international community is critical to research efficiency and to maximizing the millions of dollars in research funding. New restrictions on importation of zebrafish into Canada based on putative susceptibility to infection by the spring viremia of carp virus (SVCV) have been imposed on the scientific community. In this commentary, we review the disease profile of SVCV in fish, discuss the findings of the Canadian government's scientific assessment, how the interpretations of their assessment differ from that of the Canadian research community, and describe the negative impact of these regulations on the Canadian research community and public as it pertains to protecting the health of Canadians.

Restrictions on the Importation of Zebrafish into Canada Associated with Spring Viremia of Carp Virus.

A visual aid for computer-based analysis of sleep-wake state in rats.

/pdf/response-to-protocol-review-scenario-before-the-amendment-4snoe7vi3m.pdf

Rhain P. Louis

Papers

Design and validation of a computer-based sleep-scoring algorithm.

Restrictions on the Importation of Zebrafish into Canada Associated with Spring Viremia of Carp Virus.

A visual aid for computer-based analysis of sleep-wake state in rats.

Response to Protocol Review Scenario: Before the amendment.