Sleep and Biological Rhythms Sarah Chollar 11/2/09

What is Sleep? Sleep as a behavior American Heritage Dictionary Sleep: A natural periodic state of rest for the mind and body, in which the eyes usually close and consciousness is completely or partially lost, so that there is a decrease in bodily movement and responsiveness to external stimuli. During sleep the brain in humans and other mammals undergoes a characteristic cycle of brain-wave activity that includes intervals of dreaming.

Why Sleep? Functions of Slow-Wave Sleep Functions of REM Sleep Essential for Survival Reduction of Free Radicals Functions of REM Sleep Promote Brain Development Facilitate Learning Sleep and Learning Consolidation of long-term memories REM: consolidation of nondeclarative memory Slow-wave: consolidation of declarative memory

Species specific hours of sleep per day, large differences found between species. What types of factors contribute to this difference? Horses 2.9 hours Bats 19.9 hours

REM Sleep and Development

Studying Sleep Invasive Techniques Noninvasive Techniques Electroencephalography (EEG) is a noninvasive tool used to study phenomena related to sleep Activity of a population of neurons recorded through electrodes on scalp Electromyogram (EMG) Electro-oculogram (EOG) http://people.brandeis.edu/~sekuler/eegERP.html

Patterns of Activity Alpha: smooth, medium frequency 8-12 Hz Beta: irregular, low amplitude 13-30 Hz Theta: 3.5-7.5 Hz activity Delta: activity less than 4 Hz Sleep spindles: short bursts of 12-14 Hz K complexes: sudden sharp waveforms

Stages of Sleep Awake: Alpha and beta, desynchronous Stage 1: Theta, more synchronous Stage 2: Irregular with periods of theta activity, sleep spindles, and K complexes Stage 3: High amplitude delta (20-50%) Stage 4: More than 50% delta Stages 3 and 4 considered to be slow wave sleep (SWS)

Stages of Sleep

Stages of Sleep

Sleep and Memory Nap Studies (Mednick et al., 2003) Slow wave sleep (SWS) Consolidation of declarative memory REM sleep Consolidation of nondeclarative memory

Physiological Mechanisms Chemical control Adenosine Neural control of arousal Acetylcholine Norepinephrine Serotonin Histamine Orexin Neural control of slow-wave sleep Ventrolateral Preoptic Area (vlPOA) Neural control of REM sleep Sublaterodorsal Nucleus (SLD) Ventrolateral Periaqueductal Gray Matter (vlPAG) http://www.cellscience.com/Reviews5/Mobbs1.jpg

Brain Structures for Arousal and Sleep Pineal Gland Ventrolateral Preoptic Area (vlPOA) Suprachiasmatic Nucleus (SCN) Optic Chiasm Hypothalamus

Anatomical Structures Related to Sleep

Neurotransmitter Systems Norepinephrine Acetylcholine (Ach) Histamine GABA Serotonin

Sleep and Arousal: The Balance Activity in areas involved in arousal will inhibit areas involved in sleep Activity in areas that promote sleep will inhibit areas involved in arousal

Biological Clocks Circadian Rhythms and Zeitgebers Circadian Rhythms – daily rhythmical change in behavior or physiological process. Zeitgebers – stimuli that resets the biological clock responsible for circadian rhythms. The Suprachiasmatic Nucleus A hypothalamic nucleus containing the biological clock for many of the body’s circadian rhythms. Melanopsin – photopigment in retinal ganglion cells that project to the SCN.

Daily Changes in Body Temperature

Circadian rhythm of body temperature

Genetic Control of Sleep and Arousal

Sleep Disorders Insomnia Sleep Apnea Narcolepsy REM Sleep Behavior Disorder SWS Problems Nocturnal Enuresis – bedwetting. Somnambulism – sleepwalking. Pavor Nocturnus – night terrors. Sleep-Related Eating Disorder – eating during sleepwalking, often without recollection. Ambien?

Orexin and Arousal Orexin activates brain stem and forebrain arousal systems Promotes wakefulness Narcolepsy problems with orexin producing neurons and receptor B

Ambien www.ambiencr.com AMBIEN CR is indicated to help you fall asleep and/or stay asleep. AMBIEN is indicated for short-term treatment to help you fall asleep. IMPORTANT SAFETY INFORMATION AMBIEN and AMBIEN CR are treatment options you and your doctor can consider along with lifestyle changes. When taking either of them, don’t drive or operate machinery. Plan to devote 7 to 8 hours to sleep before being active. Sleepwalking, and eating or driving while not fully awake, with memory loss for the event, as well as abnormal behaviors such as being more outgoing or aggressive than normal, confusion, agitation, and hallucinations may occur. Don’t take it with alcohol as it may increase these behaviors. In patients with depression, worsening of depression, including risk of suicide may occur. If you experience any of these behaviors contact your doctor immediately. Allergic reactions such as shortness of breath, swelling of your tongue or throat, may occur and in rare cases may be fatal. If you have an allergic reaction while using AMBIEN or AMBIEN CR, contact your doctor immediately. Side effects of AMBIEN CR may include next-day drowsiness, dizziness and headache. There is a low occurrence of side effects associated with the short-term use of AMBIEN. The most commonly observed side effects in controlled clinical trials were drowsiness, dizziness, and diarrhea. AMBIEN is taken for 7 to 10 days –or longer as advised by your provider. AMBIEN CR can be taken as long as your doctor recommends. AMBIEN and AMBIEN CR have some risk of dependency. They are non- narcotic www.ambiencr.com

Melatonin Pineal Gland produces melatonin and plays a role in circadian and seasonal rhythms. Melatonin: hormone secreted during the night by the pineal gland, plays a role in circadian and seasonal rhythms. Can affect sensitivity of SCN neurons to zeitgebers Connections from the SCN to the PVN

Dreaming Activation-synthesis hypothesis Clinico-Anatomical hypothesis Contemporary Research Crosses many disciplines: psychoanalysis, sociology, neuroscience, psychology Content analysis Historical Perspectives Freud Dream interpretation

PGO Activity