Chapter 9 Wakefulness and Sleep

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Chapter 9Wakefulness and Sleep
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Rhythms of Waking and Sleep

• Animals generate endogenous 24 hour cycles of
  wakefulness and sleep.

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Rhythms of Waking and Sleep

• Endogenous circadian rhythms

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Fig. 9-2, p. 267
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Rhythms of Waking and Sleep

• Mechanisms of the circadian rhythms include the
  following
• The Suprachiasmatic nucleus.
• Genes that produce certain proteins.
• Melatonin levels.

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Rhythms of Waking and Sleep

• Suprachiasmatic nucleus (SCN)

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Fig. 9-4, p. 269
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Rhythms of Waking and Sleep

• Two types of genes are responsible for generating
  the circadian rhythm.
• Period - produce proteins called Per.
• Timeless - produce proteins called Tim.

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Fig. 9-5, p. 270
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Rhythms of Waking and Sleep

• The SCN regulates waking and sleeping by
  controlling activity levels in other areas of the
  brain.

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Stages of Sleep And Brain Mechanisms

• Sleep is a specialized state that serves a
  variety of important functions including
• conservation of energy.
• repair and restoration.
• learning and memory consolidation.

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Stages of Sleep And Brain Mechanisms

• The electroencephalograph (EEG) allowed
  researchers to discover that there are various
  stages of sleep.

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Stages of Sleep And Brain Mechanisms

• Alpha waves
• Stage 1 sleep
• Stage 2 sleep
• Sleep spindles
• K-complexes
• Stage 3 and Stage 4
• Non-REM (NREM)

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Stages of Sleep And Brain Mechanisms

• Rapid eye movement sleep (REM)

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Fig. 9-9, p. 276
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Stages of Sleep And Brain Mechanisms

• Various brain mechanisms are associated with
  wakefulness and arousal.
• reticular formation
• Pontomesencephalon
• locus coeruleus
• basal forebrain
• Hypothalamus
• Orexin

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Table 9-1, p. 280
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Fig. 9-11, p. 279
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Fig. 9-12, p. 280
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Stages of Sleep And Brain Mechanisms

• During REM sleep
• Activity increases in the pons (triggers the
  onset of REM sleep), limbic system, parietal
  cortex and temporal cortex.
• Activity decreases in the primary visual cortex,
  the motor cortex, and the dorsolateral prefrontal
  cortex.

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Stages of Sleep And Brain Mechanisms

• Atonia

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Sleep Disorders

• Insomnia
• Sleep apnea
• Narcolepsy
• Cataplexy
• REM behavior disorder

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Stages of Sleep And Brain Mechanisms

• Parasomnias
• Night terrors
• Sleep talking
• Sleepwalking
• Sleep eating
• Sleep driving

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Why Sleep? Why REM? Why Dreams?

• Conserve energy
• Restorative processes

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Why Sleep? Why REM? Why Dreams?

• Enhancing learning and strengthening memory

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Why Sleep? Why REM? Why Dreams?

• Humans spend one-third of their life asleep.
• One-fifth of sleep time is spent in REM.

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Why Sleep? Why REM? Why Dreams?

• REM deprivation
• REM Rebound
• Research is inconclusive regarding the exact
  functions of REM.

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Why Sleep? Why REM? Why Dreams?

• Accuracy of dreams
• Two biological theories of dreaming include
• The activation-synthesis hypothesis.
• 2. The clinico-anatomical hypothesis.