seconds. They can occur spontaneously or in response to auditory stimuli. Generally quiescent, no eye movements. EMG: Moderate tonic activity. 4. Stage N3 (Non-REM Stage 3) - Slow-Wave Sleep (SWS)
). Frontal channels excel at capturing high-amplitude slow waves, central channels optimize the detection of sleep spindles, and occipital channels best reflect the alpha rhythms of relaxed wakefulness. The Core EEG Waveforms
Sleep plays a crucial role in:
Content: Alpha rhythm criteria for Wake; LAMF and vertex sharp waves for N1 transition.
). To score a page as N3, these slow waves must occupy at least 20% of the 30-second epoch. eeg and sleep physiology ppt
Sleep is not a passive state of inactivity. Instead, it is an active, highly organized biological process regulated by complex neural circuits. Understanding sleep requires looking at two primary biological mechanisms:
Sleep is a fundamental biological process necessary for survival, cognitive function, and physical restoration. Understanding how we sleep requires studying the brain's electrical activity, which is primarily achieved through .
To study sleep objectively, clinicians use Polysomnography (PSG), a multi-parametric test that records various body functions during sleep. A standard PSG presentation slide should highlight these three essential biopotentials:
Waveform Frequency (Hz) Associated State --------------------------------------------------------- Beta 13 – 30 Hz Active wakefulness, intense focus Alpha 8 – 12 Hz Relaxed wakefulness (eyes closed) Theta 4 – 7 Hz Drowsiness and light sleep Delta 0.5 – 3.5 Hz Deep, slow-wave sleep 2. Neurobiology of the Sleep-Wake Cycle seconds
Classification of Brain Waves (Beta, Alpha, Theta, Delta) Slide 6: NREM Stage 1 (N1) – Key Features and EEG Tracing Slide 7: NREM Stage 2 (N2) – Sleep Spindles & K-Complexes Slide 8: NREM Stage 3 (N3) – Slow-Wave Sleep Dynamics Slide 9: REM Sleep – The Paradoxical Brain and Atonia
Sleep studies (polysomnography) use EEG alongside other measurements to diagnose: Sleep Apnea Narcolepsy Parasomnias (e.g., night terrors, sleepwalking)
: Observed during relaxed wakefulness with eyes closed, primarily over the occipital and parietal regions.
An effective PPT on sleep physiology must include a visual or descriptive breakdown of standard EEG frequencies. Brain waves are categorized by their frequency (Hertz, or cycles per second) and amplitude: EMG: Moderate tonic activity
Electroencephalography (EEG) is the cornerstone of modern sleep medicine. By recording the brain's electrical activity, EEG allows scientists and clinicians to peer into the sleeping brain, mapping out distinct stages and identifying sleep disorders.
seconds), which fragment sleep and eradicate deep N3 and REM stages.
Often called "paradoxical sleep" because the brain is highly active while the body is completely paralyzed (muscle atonia) to prevent acting out dreams. This stage is critical for emotional regulation and memory consolidation.
Rapid, conjugate eye movements (EOG) and profound muscle atonia (paralysis seen on EMG), punctuated by transient muscle twitches. 5. Clinical Relevance: Abnormal EEG Patterns in Sleep