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Chapter 9 Wakefulness and Sleep. Rhythms of Waking and Sleep. Animals generate endogenous 24 hour cycles of wakefulness and sleep. Rhythms of Waking and Sleep. Endogenous circadian rhythms. Fig. 9-2, p. 267. Rhythms of Waking and Sleep. - PowerPoint PPT Presentation
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Chapter 9Wakefulness and Sleep
Rhythms of Waking and Sleep
• Animals generate endogenous 24 hour cycles of wakefulness and sleep.
Rhythms of Waking and Sleep
• Endogenous circadian rhythms
Fig. 9-2, p. 267
Rhythms of Waking and Sleep
• Mechanisms of the circadian rhythms include the following:– The Suprachiasmatic nucleus.– Genes that produce certain proteins.– Melatonin levels.
Rhythms of Waking and Sleep
• Suprachiasmatic nucleus (SCN)
Fig. 9-4, p. 269
Rhythms of Waking and Sleep
• Two types of genes are responsible for generating the circadian rhythm.1. Period - produce proteins called Per.2. Timeless - produce proteins called Tim.
Fig. 9-5, p. 270
Rhythms of Waking and Sleep
• The SCN regulates waking and sleeping by controlling activity levels in other areas of the brain.
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.
Stages of Sleep And Brain Mechanisms
• The electroencephalograph (EEG) allowed researchers to discover that there are various stages of sleep.
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)
Stages of Sleep And Brain Mechanisms
• Rapid eye movement sleep (REM)
Fig. 9-9, p. 276
Stages of Sleep And Brain Mechanisms
• Various brain mechanisms are associated with wakefulness and arousal.
• reticular formation• Pontomesencephalon• locus coeruleus• basal forebrain• Hypothalamus
– Orexin
Table 9-1, p. 280
Fig. 9-11, p. 279
Fig. 9-12, p. 280
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.
Stages of Sleep And Brain Mechanisms
• Atonia
Sleep Disorders
• Insomnia
• Sleep apnea
• Narcolepsy– Cataplexy
• REM behavior disorder
Stages of Sleep And Brain Mechanisms
• Parasomnias– Night terrors– Sleep talking– Sleepwalking– Sleep eating– Sleep driving
Why Sleep? Why REM? Why Dreams?
• Conserve energy
• Restorative processes
Why Sleep? Why REM? Why Dreams?
• Enhancing learning and strengthening memory
Why Sleep? Why REM? Why Dreams?
• Humans spend one-third of their life asleep.
• One-fifth of sleep time is spent in REM.
Why Sleep? Why REM? Why Dreams?
• REM deprivation
• REM Rebound
• Research is inconclusive regarding the exact functions of REM.
Why Sleep? Why REM? Why Dreams?
• Accuracy of dreams…• Two biological theories of dreaming include:
1. The activation-synthesis hypothesis.
2. The clinico-anatomical hypothesis.