Eeg And Sleep Physiology Ppt

Process C is an internal, biological clock operating on a roughly 24-hour cycle.

These are disorders of arousal that occur out of slow-wave sleep (N3). The EEG often displays a sudden dissociation—features of wakefulness mixed with persistent delta activity, showing the brain is stuck between states.

Sleep is not simply the absence of wakefulness. It is defined as a reversible, neurobehavioral state characterized by reduced awareness, altered metabolism, and distinct patterns of brain activity. Sleep is an active physiological process that is highly conserved across species, meaning it is fundamental to survival. On average, humans spend approximately 23 years of their lives asleep, but the quality and architecture of this sleep are far more critical than duration alone.

A healthy young adult spends roughly 5% of the night in N1, 50% in N2, 20% in N3, and 25% in REM. The first half of the night is dominated by deep slow-wave sleep (N3), while the second half contains longer periods of Rapid Eye Movement (REM) sleep. Slide 5: Non-REM Stage 1 (N1) – Transition to Sleep eeg and sleep physiology ppt

: High brain metabolic activity coupled with complete somatic muscle paralysis.

Conclude by linking healthy sleep architecture to real-world pathophysiological abnormalities, demonstrating the real-world utility of EEG sleep staging.

An electroencephalogram (EEG) is a non-invasive, safe, and painless diagnostic test that records electrical activity generated by brain neurons. It is the cornerstone of , which is the gold standard for diagnosing sleep disorders. Process C is an internal, biological clock operating

Sleep is a naturally recurring state of mind and body, characterized by altered consciousness, inhibited sensory activity, and inhibition of nearly all voluntary muscles.

A full night’s sleep consists of several 90-to-120-minute cycles, alternating between NREM (N1, N2, N3) and REM sleep. As the night progresses, the duration of N3 (deep sleep) decreases, while the duration of REM sleep increases. Dominated by N3 (deep delta waves). Late Night: Dominated by N2 and REM. 4. Clinical Significance of Sleep EEG

Stage N2 forms the bedrock of a night's sleep, occupying roughly 45–55% of total sleep duration. This stage marks the definitive onset of true sleep. Sleep is not simply the absence of wakefulness

A "sleep pressure" or drive that builds up the longer we are awake. It is linked to the accumulation of adenosine (which caffeine blocks) in the brain. Neurotransmitters like GABA (in the preoptic area) promote sleep, while Orexin/Hypocretin (in the lateral hypothalamus) promotes wakefulness and stability.

Complete muscle atonia (paralysis). The brain actively inhibits lower motor neurons via glycinergic and GABAergic pathways to prevent the physical acting out of vivid dreams.