Chapter 12: Wakefulness and Sleep

Endogenous Cycles 1. Many animals have a circannual rhythm 2. Most animals, including humans have a circadian rhythm  What do you think this means?

How long is the natural Human Circadian Rhythm? 1. Our internal daily rhythm actually lasts a little longer than 24 hours. 2. How do we know that?

What is the Biological Clock? 1. This internal, daily rhythm is what psychologists refer to as the biological clock  Different from the way it is used in Hollywood!! 2. While it can be manipulated by external factors, the clock is an INTERNAL mechanism

What Controls the Biological Clock? 1. Brain areas 2. Glands 3. Hormones 4. Neurotransmitters 5. External influences

Suprachiasmatic Nucleus 1. The hypothalamus is responsible for controlling the internal mechanisms of hunger, sexual arousal, body temp, etc. 2. The suprachiasmatic Nucleus (SCN) is an area of the hypothalamus that controls the biological clock  How would you guess we know that?  Damage and… hamsters

Melatonin 1. Part of the SCN’s function is to control glands that release hormones  pineal gland 2. The pineal gland controls the release of melatonin 3. What would you guess melatonin’s function is?

Can we Manipulate the Clock? 1. First, what ‘sets’ the clock?  The zeitgeber  Location of the SCN & link to the retina  How can animals who can’t see light set the clock? 2. Can you think of any circumstances where you would want to manipulate the clock?  Traveling to other time zones  Shift work  Newborns

Jet Lag 1. Has everyone here experienced Jet Lag?  When does it happen?  What does it feel like? 2. Constantly adjusting and re-adjusting can actually be bad for the body  Stress hormones increase – heart problems  Even brain changes with functional consequences

Shift work 1. Can we effectively override the circadian rhythm and shift our bodies to be awake at night and sleep all day? 2. While we CAN do it, we never do it very well (no matter how long we are on that schedule)

What is Sleep?  Can anyone describe it to me?  Sleep is …  Sleep has a distinct biological rhythm  About every 90 minutes we cycle through 5 stages of sleep

How do we get to sleep? 1. Decreasing stimulation 2. Temperature changes 3. Inhibit the arousal centers of the brain, namely the forebrain

The Stages of Sleep  Stage one  Stage two SLOW-WAVE SLEEP  Stage three  Stage four

The ‘5 th ’ Stage  REM sleep  We know that activity in the pons is what ‘triggers’ REM sleep  There is a pattern of brain activity from pons to the thalamus and then to the occipital cortex  The limbic system is also activated during REM

The Cycle  1  2  3  4  3  2  REM  In other words, the ‘5 th stage’ of sleep doesn’t happen right after stage 4!  We cycle back up & have REM instead of stage 1  We don’t spend equal amounts of time in each stage during the night

How much Sleep do we Need? 1. The answer varies based on factors such as age  Newborns spend  Older adults  Teenagers 2. Most adults allowed to sleep as long as they like will tend to go about 9 hours

Theories about why we Sleep 1. As an evolutionary protective mechanism 2. Sleep is a restorative function 3. Growth may occur during sleep

Why REM? 1. REM is necessary, with out it we become irritable and ADD-like 2. Maybe involved in learning and memory  The consolidation process is a good candidate  Research is mixed 3. Weird Eyeball theory

Why Dreams? 1. Activation-synthesis hypothesis 2. Clinico-anatomical hypothesis

Insomnia  Insomnia, three kinds: 1. ONSET insomnia 2. MAINTENANCE insomnia 3. TERMINATION insomnia  Screw-ups in the body’s temperature change are associated with onset at termination insomnia 1. Phase delayed = warmer than normal at night = onset 2. Phase advanced = warmer than normal in the morning = termination

Treatments for Insomnia 1. What have you guys tried when you can’t sleep? 2. Sleeping pills and alcohol 3. Insomnia is often a behavioral issue & can be fixed with behavioral interventions

Sleep Apnea  Sleep apnea 1. You are basically waking up every few minutes all night, every night 2. You never feel rested 3. Your family will often tell you that you snore like a banshee  Often caused by obesity, related to heart damage

Treatments for Sleep Apnea 1. If obesity is a factor, lose weight 2. Cut down on alcohol and other depressants 3. Oxygen Delivery Mask  Basically forces air into your lungs  Looks really uncomfortable, but allows people to remain asleep 4. Surgery  Kids – adenoids/tonsils  Adults – excess tissue

Narcolepsy 1. Narcolepsy  Not as uncommon as you might think – 1 in 1000  Associated with cataplexy, sleep paralysis, & hypnagogic hallucinations 2. Attacks are often brought on by emotions 3. Cause may be linked to neurotransmitter problems – ACh (stem) & Hypocretin (hypothalamus)

Treatments for Narcolepsy 1. You’d think treatments would focus on the proposed causes, right?  What would this entail?  Why can’t we do that? 2. Treatment at this point is basically to load these folks up with stimulants

Restless Leg Syndrome 1. Your book calls this ‘periodic limb movement disorder’ 2. It is where as you are falling asleep your legs kick involuntarily, waking you up 3. Pharmacological interventions

REM Behavior Disorder 1. This is a relatively newly recognized disorder in which the normal REM paralysis does not occur  Occurs most frequently in older men with other brain disorder (like Parkinson’s/Alzheimer’s) 2. They frequently have aggressive dreams & act them out, injuring themselves or their sleeping partners 3. It has been used as a defense for ‘sleep- walking crime’

Night Terrors, etc. 1. Night terrors are different than your typical nightmare 2. Sleep walking often runs in families