Brain Waves, Sleep Rhythms, and Molecular Sleep Regulation

Comprehensive vocabulary flashcards covering brain wave frequencies, sleep anatomy, molecular messengers of sleep/wake cycles, and sleep physiology based on the lecture transcript.

Beta Waves

Brain waves with a frequency range of $13 - 30\,Hz$ that occur while a person is awake.

Alpha Waves

Brain waves with a frequency range of $8 - 13\,Hz$ that occur while a person is relaxed or sleepy.

Theta Waves

Brain waves with a frequency range of $4 - 8\,Hz$ that occur during stage 1 and 2 (light) sleep.

Delta Waves

Brain waves with a frequency range of $1 - 4\,Hz$ that occur during stage 3 (deep) sleep.

Alertness / Arousal

A brain state characterized by responsiveness to and interaction with the environment.

Sleep

A readily reversible state of reduced responsiveness to and interaction with the environment.

Electroencephalogram (EEG)

A tool used to measure brain waves by detecting the rhythmic, synchronized firing of thousands of neurons.

Thalamus

The brain region that acts as a pacemaker for synchronous brain rhythms.

REM Sleep

A stage comprising $25\%$ of sleep characterized by high frequency, low amplitude brain waves and dreaming.

NonREM Sleep

A state comprising $75\%$ of sleep characterized by deep sleep, slow waves, and low frequency, high amplitude patterns.

Circadian Rhythm

A $24\,hour$ cycle of behavioral states that determines when to sleep versus when to be awake.

Entrained internal clocks

Internal biological clocks that require environmental input to function.

Intrinsically photosensitive retinal ganglion cells (ipRGCs)

Cells that sense light using the photopigment melanopsin and innervate the suprachiasmatic nucleus (SCN) via the retinofugal projection.

Suprachiasmatic Nucleus (SCN)

A region of the hypothalamus that functions as a key brain area for regulating circadian rhythms.

Melatonin

An initiating molecular messenger of the endogenous biological clock released by the pineal gland in darkness.

Adenosine

A molecule that builds up throughout the day and inhibits wakefulness excitatory systems; its effects are antagonized by caffeine.

Nitric Oxide (NO)

A molecule produced by respiratory tract cells that triggers the release of adenosine and increases with sleep deprivation.

GABA

An inhibitory neurotransmitter that suppresses overall brain activity and reduces anxiety to facilitate sleep.

Interleuckin-1

Cytokines from the immune system that promote non-REM sleep and stimulate immune function.

Histamine

A chemical secreted from the midbrain that stimulates normal wakefulness throughout the brain.

Orexin

A chemical secreted by hypothalamic neurons that strongly excites systems including Acetylcholine, serotonin, dopamine, and noradrenaline.

Atonia

A complete lack of skeletal muscle tone or contractions, typically associated with REM sleep.

Sublaterodorsal tegmental nucleus (SLD)

A structure spanning the midbrain tegmentum and pons that excites neurons in the ventral medial medulla (vmM) to inhibit spinal motor neurons.

Ascending Arousal System (AAS)

Excites global arousal throughout the cortex, via several NT systems, including ATP

Beta-amyloids

Metabolic waste products flushed out of the brain by cerebral spinal fluid (CSF) during slow wave sleep.

Activation-Synthesis Theory

A theory of dreaming (Random Activation Theory) suggesting dreams have no real function and are the brain's attempt to make sense of random activity.