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Chapter 19 Brain Rhythms

I. The Electroencephalogram. A. EEG recordings 1. EEG electrodes (19.2) 2. measure voltage fluctuations between electrodes a. mV. I. The Electroencephalogram. A. EEG recordings (19.3) 3. synaptic excitation of cortical pyramidal cells 4. summation of thousands of synapses. I. The Electroencephalogram.

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Chapter 19 Brain Rhythms

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    1. Chapter 19 Brain Rhythms The EEG Sleep Circadian Rhythms

    2. I. The Electroencephalogram A. EEG recordings 1. EEG electrodes (19.2) 2. measure voltage fluctuations between electrodes a. mV

    3. I. The Electroencephalogram A. EEG recordings (19.3) 3. synaptic excitation of cortical pyramidal cells 4. summation of thousands of synapses

    4. I. The Electroencephalogram A. EEG recordings 5. synchronous activity (19.4) [neg=?]

    5. I. The Electroencephalogram B. EEG rhythms 1. beta rhythms (19.5) a. > 14 Hz b. activated cortex 2. alpha rhythms a. 8-13 Hz b. quiet, waking state

    6. I. The Electroencephalogram B. EEG rhythms 3. theta rhythms a. 4-7 Hz b. sleep state 4. delta rhythms a. < 4 Hz b. deep sleep

    7. I. The Electroencephalogram C. EEG rhythm functions 1. unknown 2. visual system parallel distributed processing a. synchronous oscillations b. different visual properties/visual areas 1) color, shape, texture, features, motion 2) face recognition

    8. I. The Electroencephalogram D. Epilepsy 1. seizures a. pathological synchronized brain activity b. general seizures c. partial seizures d. numerous causes [video: Dr. Ojemann surgery, 15 min]

    9. Skip Sleep Unless Time Permits II. Sleep A. Definition: a readily reversible state of reduced responsiveness to, and interaction with, the environment

    10. II. Sleep B. REM sleep 1. EEG: low voltage, fast waves (sim. to awake) 2. skeletal muscles paralyzed except for extraocular muscles 3. dreams 4. no temperature control 5. erection of penis/clitoris

    11. II. Sleep C. non-REM sleep 1. EEG: high voltage, slow waves 2. no paralysis 3. no dreams 4. increased parasympathetic activity

    12. II. Sleep D. The sleep cycle (19.10) 1. non-REM & REM cycles 2. every ~90 min. 3. sleep stages by EEG rhythms

    13. II. Sleep E. Neural mechanisms 1. NE, 5HT, and some ACh systems fire during awake cycle a. reticular activating system (locus coeruleus, raphe nuclei, basal forebrain and brainstem ACh neurons) 2. some ACh neurons fire during REM sleep 3. thalamic rhythms block sensory input to cortex

    14. II. Sleep Video of dreaming cat.

    15. III. Circadian Rhythms A. Definitions 1. circadian rhythm: ~ 24 hr period 2. zeitgeber: environmental cues, entrain CRs to day-night cycles (19.16) 3. free-run: CRs w/o zeitgebers 4. desynchronization: CRs on different schedules or new day-night cycle triangle=low temp

    16. III. Circadian Rhythms B. Body rhythms (19.15)

    17. III. Circadian Rhythms C. Suprachiasmatic nucleus 1. biological clock candidate 2. location (19.17)

    18. III. Circadian Rhythms C. Suprachiasmatic nucleus 3. SCN & CRs a. stimulation shifts CRs b. lesion of SCN abolishes CRs (19.18)

    19. III. Circadian Rhythms C. Suprachiasmatic nucleus c. retinohypothalamic tract d. lesion SCN and transplant new SCN (box 19.4) 1) reestablish CR of donor e. SCN in vitro (19.19) 1) CR of vasopressin release

    20. Jet Lag Video Scientific American Frontiers ~7 min

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