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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.
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Rhythms of Waking and Sleep • Animals generate endogenous 24 hour cycles of wakefulness and sleep.
Rhythms of Waking and Sleep • Endogenous circadian rhythms
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)
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.
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)
Stages of Sleep And Brain Mechanisms • Various brain mechanisms are associated with wakefulness and arousal. • reticular formation • Pontomesencephalon • locus coeruleus • basal forebrain • Hypothalamus • Orexin
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: • The activation-synthesis hypothesis. 2. The clinico-anatomical hypothesis.