Sleep

What is Sleep?

A state of relative unresponsiveness to the environment, regulated by biological clocks (circadian rhythm).

What does Circadian Rhythm refer to?

A 24-hour internal clock influencing sleep timing.

What is an Electroencephalogram (EEG)?

A non-invasive measurement of neural activity.

What occurs in N1 (Stage 1) of sleep?

Transitional stage of sleep; alpha waves transition to theta waves.

What characterizes N2 (Stage 2) sleep?

Deeper relaxation dominated by theta waves, sleep spindles, and K-complexes.

What defines N3 (Stage 3) sleep?

Deep slow-wave sleep characterized by delta waves (<3 Hz).

What is REM (Rapid Eye Movement) Sleep?

A sleep stage with darting eye movements, brain waves resembling wakefulness, and vivid dreaming.

What are Sleep Spindles?

Bursts of neural activity in N2; important for learning and memory.

What are K-Complexes?

Large waves in N2 that are responses to external stimuli.

What is the Suprachiasmatic Nucleus (SCN)?

A hypothalamic nucleus generating circadian rhythms; it receives light input.

What function does the Pineal Gland serve?

It releases melatonin, promoting sleep onset.

What is the Preservation & Protection Theory of sleep?

It suggests that sleep conserves energy and protects vulnerable animals.

What is the Body Restoration Theory of sleep?

It states that sleep repairs tissues, releases growth hormone, and lowers metabolism.

What does the Brain Maintenance Theory (REM) suggest?

It posits that REM sleep provides neuronal exercise critical for sensory-motor development.

What role does the Hypothalamus play in sleep?

It regulates sleep and circadian rhythms.

What is the function of the Thalamus during sleep?

It acts as a relay station involved in sensory input during sleep.

What role do the Pons & Reticular Formation play?

They are involved in sleep regulation, especially during REM.