Physiology of Behavior Book Notes Sleep is considered a behavior there is a change in consciousness but there is still behavior Stages of Sleep Wakefulness show alpha wave activity smooth electrical activity of 8 12 Hz produced by brain when it is resting quietly not particularly aroused excited by any stimuli or mental activity more prevalent when eyes are closed and beta wave activity irregular mostly low amp waves of 13 30 Hz shows desynchrony and reflects that many different neural circuits in brain are processing info occurs when a person is alert and attentive to events in environment or actively thinking Stage 1 starts with drowsiness marked by increased theta wave activity indicates the firing of neurons in the neocortex are becoming more synchronized about 3 5 7 5 Hz this stage is transition from awake to sleep Stage 2 Happens about 10 minutes after Stage 1 begins periods of theta activity sleep spindles short bursts of waves from 12 14 Hz that occur b w 2 5 times per minute during stage 1 and 4 of sleep appear to play role in consolidation of memory correlation b w increased S S and higher test scores and K complexes sudden and sharp waveforms usually found only in stage 2 sleep 1 per minute but can increase with sound stimulus forerunner of delta waves which appear in deepest levels of sleep consist of isolated periods of neural inhibition sound asleep but if awoken now would report that they weren t sleeping at all Stage 3 15 minutes after Stage 2 starts signaled by occurrence of high amp delta waves less than 3 5 Hz regular synchronous activity contains 20 50 delta activity considered one part of slow wave sleep along with stage 4 Stage 4 REM rapid eye movement Sleep deepest stage of sleep easily awakened by meaningful stimuli i e someone calling their name appears alert and attentive when awoken from REM dreaming occurs during REM most are narrative with story like progression of events lasts about 20 30 minutes most of spinal and cranial nerves are inhibited during this time except oculomotor and respiration causing paralysis consumption of oxygen and blood flow accelerate links to penile erection sexual arousal during REM wet dreams vaginal discharge orgasm etc desynchronized EEG activity Slow Wave Sleep Consists of sleep stages 3 and 4 Most important feature are slow oscillations lower than 1 Hz each osc consists of a single high amp biphasic down and up wave Down State period of inhibition during which neurons in the neocortex are absolutely silent neocortical neurons are put to rest Up State period of excitation during which the neocortical neurons briefly fire at a high rate Disorders of Sleep difficulty falling asleep after going to bed or after awaking during night particular form is called sleep apnea caused by an inability to breathe and sleep at the same time CO2 receptors in brain wake person up when levels get too high they gasp for air and then go back to sleep can be fixed by surgery or mask Insomnia Narcolepsy neuro disorder characterized by periods of sleep at inappropriate times primary symptom is known as sleep attack overwhelming urge to sleep that can be triggered by boring monotonous conditions another symptom is cataplexy person sustains varying amounts of muscle weakness during an attack some cases person will become completely paralyzed and fall to floor can be conscious the entire time thought to occur due to muscular paralysis that is similar to what happens in REM sleep another symptom is sleep paralysis inability to move just before onset of sleep or right after waking up hypnagogic hallucinations symptom of narcolepsy where vivid dreams occur just before person falls asleep accompanied by sleep paralysis gene on chromosome 6 affected hereditary also environmental loss of orexinergic neurons is mainly the cause most patients are born with the neurons but during puberty the immune system attacks them studies cause for canine mutation found on orexin B receptor REM Sleep Behavior Disorder neuro disorder in which person doesn t become paralyzed in REM sleep and acts out their dreams appears to be a neurodegenerative disease with genetic component can be caused by brain damage as well Problems Associated with Slow Wave Sleep bedwetting sleepwalking and night terrors sleep related eating disorder person leaves bed and seeks eats food recalls nothing the next day most researchers believe primary function of SWS is to let brain rest Why Do We Sleep primary role of sleep doesn t seem to be rest recuperation of the body but of the mind and cognition after sleep deprivation people generally sleep longer for the next few days but never make up their lost sleep long periods of waking activity causes sleep deprivation waste products made by high metabolic rate turn into free radicals highly reactive oxidizing agents can bind with electrons from other cells and damage those cells during SWS lower metabolic rate allows brain to damage some free radicals before they hurt brain body fatal familial insomnia fatal inherited disorder characterized by progressive insomnia causes damage to thalamus deficits in attention memory then dream like state then loss of control of ANS endocrine system first sign of sleep disturbances are reduction in sleep spindles and K complexes after a period of cerebral effort work slow wave sleep becomes more intense restorative rebound phenomenon increased frequency intensity of a phenomenon after it has been temporarily suppressed increase in REM sleep seen after a period of REM deprivation Functions of REM Sleep Sleep and Learning REM sleep strongly facilitates consolidation of nondeclarative memory memories gained through experience practice SWS facilitates consolidation of declarative memories memories of past episodes in life memories you can talk about brain appears to rehearse new info learned info during SWS Chemical Control of Sleep adenosine nucleoside neuromodulator in brain that might play primary role in the control of sleep inhibits neural activity astrocytes maintain a stock of glycogen during times of increased brain activity glycogen is provided to fuel neurons prolonged wakefulness causes decrease in glycogen levels and leads to emotional physical effects of being tired decrease in glycogen signals increase of adenosine adenosine deaminase breaks down adenosine genetic some people have more some less Neural Control of Arousal 5 neurotransmitters that play role in arousal acetylcholine norepinephrine serotonin