unusual examples dolphins whales sperm whale off the

unusual examples dolphins whales

sperm whale (off the coast of Chilé)

http: //www. nature. com/news/2008/080221/ multimedia/news. 2008. 613. mov

Sleep 135, 000 hours of your life asleep (1/3) How do we study sleep? What do we know about it? What are some sleep disorders What do we know about brain regions and neurotransmitters involved in sleep?

How do we study sleep typically in a sleep lab…. EEG – electroencephalogram EPSPs of cortical neurons ◦ EMG – electromyelogram looking at muscle tone (usually electrodes on jaw) ◦ EOG – electrooculogram looking at eye movements (electrodes around eye)

EEG look at 2 components of the EEG 1. the frequency of the wave (n of peaks/unit time) – tells you about the number of cortical neurons generating EPSPs 2. the amplitude of the wave (height of wave) – – tells us about the n of EPSPs that occur at the same point in time n of neurons firing in synchrony

high frequency, low amplitude beta waves

start seeing higher amplitude, lower frequency alpha waves

1 st sleep stage – still fairly high frequency low amplitude but clear difference from alert and awake state often will deny being asleep

15 min later (if not disturbed) stage 2 – characterized by high frequency low amplitude sleep spindles and high amp low f k complexes role of these wave forms? –

15 min later if not disturbed stage 3 – first of the slow wave sleep stages characterized by delta waves high amplitude, low frequency waves less than 50% delta waves is stage 3; more than 50% stage 4 (15 min later)

slow wave sleep during SWS, parasympathetic NS activity seems to predominate (hr and bp decrease, respiration decreases, gastric motility increases) person relaxed but still motor activity; normal sleeper changes position every 20 min or so stage 4 deepest stage ?

typical 90 min sleep cycles goes from ◦ stage 1 (15 min) to stage 2 (15 min) to stage 3 (15 min) to stage 4 (15 min) to stage 3 (15 min) to stage 2 (15 min) to first bout of REM sleep

Characteristics of REM sleep low amplitude, high frequency desynchronous EEG

Characteristics of REM sleep low amplitude, high frequency desynchronous EEG rapid eye movement (REM) narrative dreams muscle atonia ◦ look at motor cortex – extremely active but descending motor pathways paralyzed ◦ REM without atonia penile erections and vaginal secretions deepest stage? ◦ incorporate things into our dreams ◦ more likely to spontaneously awaken

Some characteristics of REM changes in amount of time spent in REM over the night

Some characteristics of REM changes in amount of time spent in REM over the night maturational changes in pattern ◦ species with underdeveloped CNS – spend more time in REM

Some characteristics of REM changes in amount of time spent in REM over the night maturational changes in pattern ◦ species with underdeveloped CNS – spend more time in REM ◦ human newborns ~ 50% sleep time in REM ◦ human premies ~ 80% sleep time in REM

Why do we sleep? evolutionary theory ◦ predictions…… restoration and repair

Evolutionary Theory Sleep more if: ◦ No predators ◦ Safe place for sleeping ◦ Dangerous to yourself in the dark Sleep less if: ◦ Fear of predation ◦ Food of low nutritional value

Why do we sleep? evolutionary theory restoration and repair ◦ marathon runner studies

What happens with sleep deprivation?

Sleep disorders 1. Insomnia

Sleep disorders 1. Insomnia - primary cause - sleep medications

Sleep disorders 1. Insomnia - primary cause - sleep medications - develop tolerance; REM rebound

History of pharmacological treatments for insomnia

pharmacological txt short-acting benzodiazepenes ◦ triazolam (Halcion®)

pharmacological txt short-acting benzodiazepenes ◦ triazolam (Halcion®) problems with BZ tolerance REM suppression (and REM rebound) WD

Non-Benzodiazepine Hypnotic Drugs Zolpidem- (Ambien) ◦ ◦ non hypnotic sedative Also a muscle relaxant and anticonvulsant Still works on GABA A receptors Works quickly (15 min) and with a short ½ life (how quickly it clears out of the body

The pineal gland releases hormone melatonin at night

Ramelteon (Rozerem) ◦ ◦ First in a new class of sleep medications non BZ non sedative melatonin agonist

Sleep disorders 1. Insomnia - primary cause - sleep medications - develop tolerance; REM rebound - we are often poor estimators of how much sleep we get

-sleep apnea – difficulty sleeping and breathing at the same time - two types - 1. CNS mediated – very rare - 2. obstructive sleep apnea- main cause

treatments weight loss, reducing alcohol consumption (or other muscle relaxants), elevated sleeping, CPAP machine – continuous postive airway pressure surgical procedures to remove or tighten tissue

SIDS – sudden infant death syndrome ◦ possible link

Insomnia Nocturnal myoclonus – twitching of the body, usually the legs, during sleep – most are not aware of why they don’t feel rested (now called periodic limb movement disorder); involuntary Restless legs – sufferers complain of legs being uncomfortable that prevents sleep- can occur when awake or asleep Txt can include DA agonists; anticonvulsants Copyright © 2006 by Allyn and Bacon

REM-related sleep disorder Narcolepsy ~ 250, 000 people in US ◦ symptoms: uncontrollable recurring sleep during daytime (usually during mundane tasks) ◦ subcategories cataplexy hypnagogic hallucinations REM sleep behavior disorder

often (not always) older males often (not always) associated with other neurodegenerative diseases

Neuroanatomical regions and NT brainstem structures – pons, medulla abnormalities in noradrenergic, cholinergic, and serotonergic systems, seems to exist in the pathogenesis of RBD clonazepam (Klonopin) ◦ anticonvulsant – ◦ benzodiazpene

Narcolepsy unusual sleep characteristics ◦ short latency to REM ◦ persistent muscle tone ◦ excessive muscle twitching Treatment for narcolepsy ◦ stimulants; caffeine, ◦ GHB – gamma hydroxy butyrate**

genetics of narcolepsy ◦ people with family history + are 50 X more likely to have disorder than families without history + ◦ animal species

Non-REM sleep disorders ◦ Enuresis ◦ Sleep walking

brain regions and NT involved in sleep locus coerulus- in hindbrain (NE transmitter) ◦ important for arousal What does it do during sleep?

brain regions and NT involved in sleep and arousal locus coerulus- in hindbrain (NE transmitter) ◦ important for arousal What does it do during sleep? ◦ active when awake; inhibited during sleep – particularly REM

What about other nt and regions? Acetylcholine – in pons – important for REM onset ◦ ACh. E poisoning (mustard gas or pesticides) people go into REM immediately after falling asleepvery vivid dreams and nightmares! PGO waves –

Serotonin (5 HT) Increases in tryptophan – increases in 5 HT Increases in 5 HT – increases in drowsiness (? )