Throughout sleep, there are different stages characterized by the presence or absence of types of brain waves. Typically, we cycle through these stages 4-5 times a night, sleeping on average 7-8 hours. These stages are broken down into two categories:

- Non-REM
- REM

Sleep Stages

The partial or total prevention of sleep. Side effects could include hallucinations, but most commonly witnessed effects are increases irritability, decreased ability to concentrate, and episodes of disorientation. Cognitive deficits are noticeable. Prolonged sleep deprivation compromises the immune system in mammals and can lead to death.

Sleep deprivation

The exact reasons we sleep are unclear and hotly debated, but there are four main explanations:

- Energy conservation
- Niche adaptation
- Body restoration
- Memory consolidation

Biological functions of sleep

Sleep library

Sleep regularity refers to whether a person sleeps and wakes at a consistent time. 

Sleep Regularity

Sleep onset is when a person transitions from a state of wakefulness and falls asleep.

Sleep Onset

A drug that renders an individual unconscious. Examples include barbiturates and anesthetic gases. They produce slow waves in the EEG that resemble the ones seen in slow wave sleep, suggesting that they tap into existing brain networks that promote sleep. Almost all are non-competitive agonists at GABA(A) receptors, boosting GABA’s inhibitory effect on neurons.

General Anesthetics

This study investigated sleepers' abilities to filter and allocate their attention towards the most relevant source of information when presented with two streams of dialogue. As of the study, there had been no evidence that the sleeping brain could covertly select which piece(s) of information to prioritize when exposed to multiple pieces of information. This study aims to see if the sleeping brain will amplify meaningful speech compared to irregular signals.

"Sleepers Track Informative Speech in a Multi-talker Environment" Legendre et al. (2019)

Sleep Library

Sleep-Wake Disorders are defined using a multidimensional approach due to the expectations for co-existing or comorbid diagnosis in both mental and neurological health. They are largely characterized by individual’s interpretation of having dissatisfying sleep quality, timing, or amount of sleep. These complaints are often expressed alongside issues of distress or impairment during expected daytime activities. 

Sleep-Wake Disorders

The sleep-wake cycle is a fundamental circadian rhythm that is internally regulated by the body's biological clock. This process governs the daily pattern of sleeping and waking, ensuring it is synchronized with the 24-hour light-dark cycle of the environment.

Sleep-Wake Cycle

Sleep-wake cycles are regulated by several brain areas working together. The thalamus, hypothalamus, and pons are key regions in this coordination: the hypothalamus includes the SCN, described as the body's biological clock, other hypothalamic nuclei work with the thalamus to regulate slow-wave sleep, and the pons helps regulate rapid eye movement (REM) sleep.

Brain Areas Regulating Sleep

- Sleep stages
- Sleep patterns over a lifetime
- Sleep onset
- Sleep regularity
- Biological functions of sleep
- Neural systems underlying sleep
- Sleep deprivation
- General anesthetics
- Sleep disorders
- Tracking Information During Sleep
- Sleep-wake cycle

University of Rochester

Grinnell College

Columbia University

Johns Hopkins University

California Polytechnic State University, San Luis Obispo

- Types of biological rhythms
- Sleeping and waking
- Changes in biological rhythms
- Suprachiasmatic Nucleus

Focuses of Biological Rhythms

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

The endogenous clock can be adjusted through a variety of means, though the most common is light. 
- Phase shift
- Entrainment 


Changes in biological rhythms

Sleeping and waking

- Circadian rhythms
- Infradian rhythms
- Ultradian rhythms
- Free-running

Learn Before

Related

Learn After