Sleep and Dreaming Sleep and Dreaming Methodology Methodology PAGE 48 PAGE 48
Dec 23, 2015
Sleep and DreamingSleep and Dreaming
MethodologyMethodology
PAGE 48PAGE 48
EEGEEGelectroencephalogramelectroencephalogram
EEGEEG
An electroencephalogram (EEG) is a recording of brain activity.
The brain's cells produce tiny electrical signals when they send messages to each other. During an EEG test, small electrodes are placed on to your scalp.
They pick up your brain's electrical signals and send them to a machine called an electroencephalograph, which records the signals as wavy lines on to a computer screen or paper.
An EEG is painless, takes 30-45 minutes and rarely causes any side effects.
EEGs can also be used to diagnose and manage sleep disorders such as insomnia.
EMGEMGElectromyogramElectromyogram
EMGEMG
Definition: A measurement of the electrical activity of skeletal muscles are recorded with the placement of small metal discs, called "electrodes," applied to the skin’s surface.
It is useful for assessing nerve and muscle function, diagnosing restless legs syndrome and determining REM versus non-REM sleep.
The electrodes are generally placed on the chin and along the shin in sleep studies.
EOGEOGElectrooculogramElectrooculogram
EOGEOG
An automated method for detecting and counting eye movements.
Using the electrooculogram (EOG) wave form during rapid-eye-movement (REM) sleep is presented.
To measure eye movement, pairs of electrodes are typically placed either above and below the eye or to the left and right of the eye.
If the eye moves from centre position toward one of the two electrodes, this electrode "sees" the positive side of the retina and the opposite electrode "sees" the negative side of the retina.
What limitations might these What limitations might these measures have?measures have?
EEG cannot determine what areas of the brain are active.
EEG determines neural activity that occurs below the upper layers of the brain (the cortex) poorly.
Often takes a long time to connect a subject to equipment, as it requires precise placement of dozens of electrodes around the head and the use of various gels, saline solutions, and/or pastes to keep them in place.
These measures tell us what is moving, but not why it is moving, we
can only infer reasons..
Biorhythms, Sleep and Biorhythms, Sleep and DreamingDreaming
Sleep Stages and CyclesSleep Stages and Cycles
Page 51Page 51
Stages of SleepStages of Sleep
Wakefulness Wakefulness • Beta wavesBeta waves
Low aplitude, high frequency waves of electrical activity Low aplitude, high frequency waves of electrical activity in the brainin the brain
Stages of SleepStages of Sleep
RelaxationRelaxation• Alpha WavesAlpha Waves
High amplitude, slow frequency wavesHigh amplitude, slow frequency waves
Stages of SleepStages of Sleep
Hypnagogic stateHypnagogic state• Muscles active, Muscles active,
Slow eye movementsSlow eye movements
Stage 1 of SleepStage 1 of Sleep
Theta waves –Theta waves – Slow frequency, irregular amplitudeSlow frequency, irregular amplitude
Stage 2Stage 2
Sleep SpindlesSleep Spindles Medium amplitude, slow frequency with bursts Medium amplitude, slow frequency with bursts
of high frequency.of high frequency. K-Complexes – brain is responsive to external K-Complexes – brain is responsive to external
stimulistimuli Eye and muscle movements are limited, Eye and muscle movements are limited, Easily wokenEasily woken
Sleep spindles/k-complexSleep spindles/k-complex
Stage 3Stage 3
Delta WavesDelta Waves Increased amplitude, slower frequency (20-Increased amplitude, slower frequency (20-
50%)50%) NREMNREM Brain unresponsive to external stimuliBrain unresponsive to external stimuli Difficulty in wakingDifficulty in waking
Delta WavesDelta Waves
Stage 4Stage 4
Increase of delta waves to more than 50%Increase of delta waves to more than 50% Lowest readings of heart rate, blood Lowest readings of heart rate, blood
pressure and temperaturepressure and temperature NREM, NREM, Brain unresponsive to stimuliBrain unresponsive to stimuli Difficulty in WakingDifficulty in Waking
REMREM
Rapid Eye Movements observedRapid Eye Movements observed Wildly oscillating brain wavesWildly oscillating brain waves Muscles in virtual paralysisMuscles in virtual paralysis Fluctuations in heart rate, blood pressure Fluctuations in heart rate, blood pressure
and respirationand respiration Difficulty in wakingDifficulty in waking
REM sleepREM sleep
Sleep CyclesSleep CyclesFirst CycleFirst Cycle
Hypnagogic stateHypnagogic state Stage 1Stage 1 Stage 2Stage 2 Stage 3Stage 3 Stage 4Stage 4 Stage 3Stage 3 Stage 2Stage 2 REMREM
1 min1 min 20 mins20 mins 5 mins5 mins 40 mins40 mins 5 mins5 mins 10 mins10 mins 10 mins10 mins
Second CycleSecond Cycle
Stage 2Stage 2 Stage 3Stage 3 Stage 4Stage 4 Stage 3Stage 3 Stage 2Stage 2 REMREM
25 mins25 mins 5 mins5 mins 30 mins30 mins 5 mins5 mins 10 mins10 mins 10 mins10 mins
Third CycleThird Cycle
Stage 2Stage 2 REMREM
30 mins30 mins 40 mins40 mins
44thth Cycle Cycle
Stage 2Stage 2 REMREM
70 mins70 mins 60 mins60 mins
55thth Cycle Cycleemergent cycleemergent cycle
Stage 2Stage 2 REMREM Hypnopompic stateHypnopompic state
May wakeMay wake May wakeMay wake
What have you learned?What have you learned?
Page 56,Page 56,
Have a go at the exam answer (8 marks, not Have a go at the exam answer (8 marks, not 9!)9!)
This is all AO1This is all AO1
““Outline the nature of sleep”Outline the nature of sleep”