Lecture 4 - Lecture 4 Sleep Basics Brain Mechanisms Awake NREM and REM Lecture 4 Sleep Mechanisms • Neurochemistry(substances •

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Unformatted text preview: 9/7/2009 Lecture 4 Sleep Basics Brain Mechanisms: Awake, NREM and REM Lecture 4 Sleep Mechanisms • Neurochemistry (substances) • Neurophysiology (electrical activity) • Functional Anatomy (brain activation) Lecture 4 Sleep Mechanisms Neurochemistry (substances) 1 9/7/2009 Lecture 4 Primer/Detour Neurochemistry (substances) Neurotransmitters Neuromodulators i.e. Turn ON or turn OFF the “radio” i.e. Tune the stations in or out (signal/noise) – or volume control Lecture 4 Primer/Detour Neurochemistry (substances) Neurotransmitters Neuromodulators • Acetylcholine (ACh) • Glutamate excitatory (makes neurons fire) • Noradenaline (NA) • Serotonin (5-HT) • GABA inhibitory (prevents neurons from firing) • Histamine (HIST) • Dopamine (DA) Lecture 4 Primer/Detour Neurochemistry (substances) Neuromodulators Noradenaline (NA) system Serotonin (5 -HT) system (5- Acetylcholine (ACh) syste m 2 9/7/2009 Lecture 4 Sleep Mechanisms Neurochemistry (substances) The Neurochemistry of the Wake-Sleep Cycle Active Wake NA 5-HT ACh Quiet Wake ++ + ++ + NREM (SWS) REM + - - +++ ACh: acetylcholine NA: noradrenaline 5HT: serotonin Lecture 4 Sleep Mechanisms Active WAKE Quiet WAKE NREM REM ACh 5-HT NA Lecture 4 Sleep Mechanisms Active WAKE Quiet WAKE NREM REM ACh 5-HT NA NA 5-HT ACh ++ + + - ++ + - +++ 3 9/7/2009 Lecture 4 Sleep Mechanisms • Neurochemistry (substances) • Neurophysiology (electrical activity) • Functional Anatomy (brain activation) Lecture 4 Brain Mechanisms for Wake and Sleep Human Brain Cortex Thalamus Brainstem Lecture 4 Brain Mechanisms for Wake and Sleep Information gate “Awareness switch” switch” (THALAMUS) Sensory Information: Hearing Sight Touch Taste Smell Activating center “Power station” station” (BRAINSTEM) BRAINSTEM) 4 9/7/2009 Lecture 4 AWAKE Active WAKE Quiet WAKE NREM REM ACh 5-HT NA ACh ++ + + - ++ NA 5-HT + - +++ Lecture 4 AWAKE (3) Information reaches cortex = Aroused & Attentive i.e. AWAKE (2) Information floods into brain from eyes, ears, nose etc... (1) Brainstem turns on electrical brain power ACh NA 5-HT Lecture 4 What does Sleep look like? EYES AWAKE EOGEOG-L Open with blinks EOGEOG-R BRAIN EEGEEG-1 High frequency (fast) Low amplitude (small) EEGEEG-2 Desynchronized EEGEEG-3 MUSCLE EEGEEG-4 EMG Strong muscle tone 30 seconds 5 9/7/2009 Lecture 4 NREM Active WAKE Quiet WAKE NREM REM ACh 5-HT NA NA 5-HT ACh Lecture 4 ++ + + - ++ + - +++ NREM X (3) No information feed to the cortex = FALL ASLEEP! (2) Gate is closed, closed, thus information cannot enter brain (1) Brainstem turns off electrical brain power **Read Reader for more detailed mechanisms!** Lecture 4 What does Sleep look like? EYES NREM (SWS) No eye movements EOGEOG-L (contamination from EEG) EOGEOG-R BRAIN EEGEEG-1 V. low frequency (SLOW) V. high amplitude (LARGE) EEGEEG-2 Synchronous brain waves EEGEEG-3 MUSCLE EEGEEG-4 EMG Lowered muscle tone 30 seconds 6 9/7/2009 Lecture 4 REM Active WAKE Quiet WAKE NREM REM ACh 5-HT NA ++ ACh + + - ++ NA 5-HT + - +++ Lecture 4 REM (3) Memories, emotions, motivations are activated in the cortex..dream! (2) Internal stimulation of the sensory gate REM’s **Read Reader for more detailed mechanisms!** (1) Brainstem partly turns on power (ACh) Lecture 4 What does Sleep look like? EYES REM EOGEOG-L Eyes closed…BUT Horizontal movements back and forth EEGEEG-1 BRAIN EOGEOG-R High frequency (fast) Low amplitude (small) EEGEEG-2 Desynchronized (like awake) EEGEEG-3 MUSCLE EEGEEG-4 EMG Absent muscle tone 30 seconds 7 9/7/2009 Lecture 4 What does Sleep look like? (summary of EEG brain waves) Active awake Relaxed awake Stage1 Stage 2 Stage 3 & 4 (“slow -wave sleep”) (“slow- REM (stage of dreaming) 1 seconds EEG : (brain wave) patterns of wake/sleep stages Lecture 4 What does Sleep look like? REM • REM sleep is also associated with a distinctive electrical brain bursts known as “PGO waves”. • These waves of neural activity are detected first in the Pons (brainstem) and then in the Geniculate of the thalamus, and then the Occipital cortex (and other sensory-motor areas). REM sleep “PGO” waves (pons-geniculate-occipital cortex) • PGO waves coincide (and may cause) the rapid eye movements of REM. Lecture 4 Sleep Mechanisms • Neurochemistry (substances) • Neurophysiology (electrical activity) • Functional Anatomy (brain activation) 8 9/7/2009 Lecture 4 Sleep Mechanisms Functional Anatomy (brain activation) • Measured using brain scanners: 1. Positron Emission Tomography (PET) 2. Functional Magnetic Resonance Imaging (fMRI) Lecture 4 Functional Anatomy of REM sleep Medial view (inner) Lateral view (outer) Lecture 4 Functional Anatomy of REM sleep Emotional Regulation (Cingulate cortex) Movement Initiation (Motor cortex) Complex Visual Processing (Occipital Cortex) Memory (Hippocampus) Emotion (Amygdala) Areas ACTIVATED during REM sleep 9 9/7/2009 Lecture 4 Functional Anatomy of REM sleep Logical Reasoning (Lateral Prefrontal Lobes) Areas ACTIVATED during REM sleep Areas DE-ACTIVATED during REM sleep Lecture 4 Functional Anatomy of REM sleep Emotional Regulation (Cingulate cortex) Movement Initiation (Motor cortex) Logical Reasoning (Lateral Prefrontal Lobes) Complex Visual Processing (Occipital Cortex) Memory (Hippocampus) Emotion (Amygdala) Areas ACTIVATED during REM sleep Areas DE-ACTIVATED during REM sleep Visual, memory-filled memoryemotional brain… without logical reasoning! Lecture 4 Lecture 4 - Summary • Sleep - controlled by very specific neurobiology e.g. changes in neurochemistry, neurophysiology and functional anatomy • Neurochemical: Awake, NREM and REM involve changes in three “neuromodulators” – Acetylcholine (ACh), Noradrenalin (NA) and Serotonin (5-HT) • Neurophysiological: These chemical changes control ascending activity from brainstem-thalamus-cortex, resulting in the unique EEG patterns of sleep • Functional Anatomy: While EEG gives a non-specific window on brain activity, neuroimaging indicates that, during REM, emotional, visual and memory areas activity, yet logical reasoning areas activity (…clues to dreaming?). 10 ...
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This note was uploaded on 10/05/2009 for the course PSYCH 133 taught by Professor Mathewwalker during the Fall '09 term at University of California, Berkeley.

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