Sleep and Waking 1 Rest Activity Cycles the physiological and behavior changes which occur a 90 minutes rest activity cycle controlled by neural center in the medulla b Living things adjust activity to predictable cyclic changes in environment c Diurnal seasonal multiyear cycles exist d Molecular Clocks more detail below i In bacteria PER and TIM genes regulation expression of CLK gene on a circadian basis in response to light control cellular metabolic activity 2 Physiological Correlates of Sleep and waking a Electromyogram EMG b Electrooculogram EOG c Electroencephalogram EEG i Records summed activity of large number of neurons summed potentials are postsynaptic potentials rather than action potentials ii Records info about cortical activity via surface electrodes iii Waking State 1 Alpha 2 Beta iv Sleep 1 Non REM sleep Non REM sleep Slow Wave Sleep SWS and REM sleep 8 13 Hz during relaxed waking state increase when close eyes 5 30 Hz desynchronized activity increase during concentration Alpha and Beta Rhythm states of consciousness Stages 1 and 2 can be awakened during this stage a Theta Waves b Stage 2 k complexes and sleep spindles reflect inhibition of information Irregular slow waves 3 8 Hz processing i K complexes periodic large amplitude potentials ii Sleep spindles bursts of 12 14 Hz waves deep sleep Stage 3 and 4 most difficult to awake 2 Slow Wave Sleep a Delta waves slow rhythmic waves 2Hz b If awakened subjects report emotion image or thought a Beta waves b Profound loss of muscle tone and eyes dart rapidly under lids c EEG patterns resemble those of awake state d Narrative dreams occur thinking occurs in all sleep stages 3 REM sleep after 60 70 minutes of stages 1 4 then EEG change abrup 15 30 Hz i High visual content poor org of temporal order of events e Blood flow increases in the occipital lobes and decreases in frontal i Metabolic activity increases in occipital areas and least in front 3 Functions of Sleep a Sleep Deprivation Studies leads to death health impairments in rats i Sleep deprivation produces increasingly strong motivation to sleep ii Total sleep deprivation results cognitive losses and impaired perform b Predators sleep more than prey suggesting ecological significant c Physical activity increase time in SWS mental learning can increase REM d REM deprivation i Rebound phenomenon may mitigate undesirable effects of NREM ii REM may be involved in learning and memory consolidation studies show that animals and humans engage in more REM after learning a task iii May be important in brain development iv e Each hemisphere sleeps independently takes turns in aquatic mammals i No blood borne hormone chemical agent that promotes inhibits sleep common insomnia snoring breathing pausing restless leg uncontrollable REM sleep attacks genetic disorder atonia paralysis upon wakening or in response to strong immediately enters REM no SWS i Four typical symptoms 4 Sleep Disorders a Narcolepsy 1 Uncontrollable sleep attacks 2 Cataplexy emotional stimulus ii Orexins dreams occurring before onset of sleep paralysis loss of muscle tone before onset of sleep 3 Hypnogogic hallucinations 4 Sleep paralysis lateral hypothalamic neurons utilizing peptide orexin 1 Degeneration of orexin hypocretinergic neurons causes narcolepsy which inhibit serotonin reuptake 1 Both NE and 5HT inhibit cholinergic neurons of the PA which control the catecholamine agonists Methylphenidate and antidepressant drugs iii Treatment onset of REM drugs inhibit the onset of REM occur in stage 4 individuals can act during REM inability to sleep i Familial fatal insomnia ii Drug dependency insomnia b REM without atonia parasomnia c Sleep waking and night terrors d Insomnia 1 Most common cause is sleeping medication results from develop Of tolerance followed by rebound symptoms if drug is withdrawn upper airway obstructions interfere with breathing leads to death in humans 5 Neural Mechanisms of Sleep and Arousal e Sleep Apnea a Sleep Induction Adenosine a nucleoside released by astrocytes when stored glucose is deplete released in response to glycogen metabolism promotes sleep Increased neuronal activity utilize glucose astrocytes convert glycogen to i glucose and release adenosine initiates sleep ii Acts on neurons in the Ventral Preoptic Area VLPA iii Infusion into the basal forebrain promotes drowsiness 1 Levels increase during wakefulness and decrease during sleep suggest important for regulating onset of sleep b In order for sleep to occur must be reduction in cortical arousal i Structures that activate cerebral cortex reticular formation brainstem parts of thalamus cholinergic neurons basal forebrain and peribrachial are of the pons 1 Cholinergic basal forebrain neurons large neurons with thick axons that use acetylcholine activate cortical neurons depolarize them c Tuberoinfondibular Area i Histamingeric neurons base of hypothalamus which is excitatory and promotes arousal 1 Project to cerebral cortex thalamus basal ganglia basal forebrain and activate basal forebrain and cortex by utilizing histamine hypothalamus d Neurotransmitter systems i Serotonin systems of the raphe nuclei become more active during cortical arousal and promote grooming behavior descending system 1 Firing of 5HT neurons decreases during SWS and none during REM acivity during sleep ascending system of the locus coerulus maintain vigilance and decrease ii Nor epinephrine sysmtem e Neural Control of Slow Wave Sleep i Ventral Preoptic Area closely associated with basal forebrain part of telencephalon located close to optic chiasm 1 Stimulation produces drowsiness lesions produces insomnia 2 Interconnected with other sleep and arousal systems 3 Connected to orexinergic systems 4 Rest activity cycle depends on reciprocal inhibition between the VLPA and arousal areas a VLPA inhibits other arousal systems that is stimulated by orexin ii Sleep promoting VLPA neurons inhibit the cortex basal forebrain and tubermammilary neurons iii Cholinergic basal forebrain neurons normally activate the cortex iv Histaminergic tuberomammilary neurons normally activate the cortex and basal froebrain v Thermoreceptors in the BF inhibit excitatory cholinergic neurons 1 Increase body temperature promotes drowsiness f Neural control of REM vi The pontine reticular formation excites choliner neurgons of basal fbrain i Peribrachial Area of the Pons 1 Cholinergic neurons control REM sleep onset by producing phenomena of controls transition from SWS to