In the NFL, who usually wins more games - East or West Coast teams? Why?
West coast teams. Athletic performance is probably better in afternoon than in the evening
Ultradian Rhythm & examples
Less than 1 day!
Repeat themselves frequently
examples:
REM sleep ~every 90 mins
BRAC = Basic rest activity cycle
Infradian Rhythm & examples
Longer than 1 day
example:
Estrous in rodents/Menstrual cycle in humans ~every 28 days
Circannual Rhythm & examples
Yearly basis
examples:
SAD = Seasonal Affective Disorder. Depression in winter, not so much in SD where lots of sun year round
Hibernation - Squirrel body weight
What does this picture about E.Coli & mice mortality rates tell us?
That what matters is not just WHAT but WHEN
If give injection in middle of night, 10-15% die
If give injection 4:00 in afternoon, ~90% die!
Melatonin
MELATONIN IS A HORMONE OF DARKNESS Always high in the night phase
Released by pineal gland
Influences circadian & circannual rhythms
Everyones melatonin rhythm similar, no matter if your nocturnal or diurnal animal
Small to non in day, great increase at night
Shown it can bifurcate also in Siberian Hamsters!
SCN Suprachiasmatic Nucleus
"Supra" (above) optic chiasm
Part of hypothalamus, biological clock depends on
Main control of circadiam rhythm for sleep & body temp
Single, isolated cells from SCN maintain circadian rhythm (adjacent cells sharpen accuracy)
When transplanted other-rhythm SCN tissue, new SCN will adopt the other rhythm
The worst time to drive a car is ___________ .
4 AM
The best time to go to the dentist is in the __________ .
Morning (If you go in the afternoon....tooth-hurty)
How light resets the SCN
Small branch of the optic nerve, the retinohypothalamic path, extends directly from the retina to the SCN
Melanopsin= special population of retinal ganglion cells that have their own photopigment. They receive input from rods & cones & even respond to light when they don't
Respond to average intensity, slowly
True or False: In Blind mole rats, even though bright light evokes no response or measurable changes in brain activity, light resets their circadian rhythm.
True
(Most of the input to that path doesn't come from normal retinal receptors)
If light regulates the CSN, then what happens to blind people?
Some set their circadian rythms by noise, temperature, meals activity
Others produce rhythms a little LONGER than 24 hour cycles. This eventually gets out of sync & may lead to sleep issues
True or False: With more sleep deprivation, there is a nice line showing a negative correlation between cognitive performance.
False
(The downward trend is actually an undulating pattern, revealing the ebbs and flows of wakefulness throughout the day & the circadian rhythm)
This Actogram shows:
Free Running Period (FRP tau), double plotted
Extra credit: Hamster wheel running rhythm in DD (constant darkness)
Proof of internal/endogenous self-sustaining oscillator/bio clock.
Circadian rhythm thats MORE than 24 hours
DD
Constant darkness
Name some things the biological clock regulates:
rest
activity
internal temperature
learning
sensation
motivation
pain tolerance/sensitivity
This Actogram shows:
Jetlag
(and the slow process of adjusting to it)
Describe the DeMarain Experiment and how he announced biological clocks/rhythms in plants
Opening & closing leaves at diff times of day
Brought into cellar – darkness
Still opened leaves when light OUTSIDE & close when dark OUTSIDE
Saw that rhythm persisted
Someone else looked closer & controlled for temp, other things
How were Aschoff bunkers used in studying biological clocks in humans?
Got volunteers, Germany, underground bunkers & paid ppl to live in them
No human contact, no TV, internet
Got them to remove themselves from sense of time
Found that they also expressed sleep/wake rhythms & ppl were on LONGER ~25 hr schedule
Must be coming from WITHIN (same thing found as plants)
ABOUT 24 hours “CIRCA DIA” = About a day
Melanopsin
Special population of retinal ganglion cells that have their own
photopigment. They receive input from rods & cones & even
respond to light when they don'tRespond to average intensity, slowly
Light -> SCN
Transcription Translation Feedback Loop (TTFL)
Components are "Clock genes"
per1 = period 1, per2 = period 2, tim = timeless
Per1 is transcribed – make mRNA – make protein per1 – gene turned on – protein moves in cell – outside nucleus – reacts to another gene product in cell – forms dimers – goes back in to nucleus – SHUTS OFF per1 gene – not being turned on – no more per1 make – degrades – loses inhibition – per1 transcribed again
THIS CYCLE TAKES ~ 24 HRS
The Hour-Glass Theory (& evidence against it)
Idea that we wear down after the day, just to "reset" later
3 all-nighters in a row
Found blips upward in cognition, when body signals it's time to be awake
Can respond to light without rods & cells Contains melanopsin: Photopigment that makes these cells light sensitive
People with lots of this more sensitive to SAD
The syndrome where people go to bed & wake up super early is called __________________
ASPS = Advanced Sleep Phase Syndrome
(Genetic component - runs in families)
The syndrome where people go to bed & wake up super late is called __________________
DSPS = Delayed Sleep Phase Syndrome
Clock gene mutants: Tau mutation
Wild-type2 normal copies~24.1 hours
Heterozygote1 normal1 mutant~22 hours
Homozygote2 mutant~20 hours
Explain the Richter studies lesioning the SCN
SCN-X where SCN surgically removed
Still did all same behaviors, but no regard to the time of day- no structure
Completely Arhythmic
In SCN-X rats (SCN removed), who were arhythmic, what drug was given & discovered to induce rhythm again?
Methamphetamine
What is the pattern of the biological clock in constant darkness (DD)?
Free-Running
What is it called when light causes a wheel-running pattern to form at the same time every day?
Entrained
What can we conclude by the result of drugs causing a rhythm again after the SCN is lesioned or removed?
That there are clocks OUTSIDE of the SCN
What happened in the LDLD experiments with rodents? How did they go from not bifurcating to bifurcation?
Turning off lights when sleeping & adding dark period in the day didn't do anything.
BUT...
Instead of total pitch dark added tiny amount of light (starlight simulation).
NOW active in each dark period, 2x/day = BIFURCATED.
Melatonin was also bifurcated. During darkness, melatonin high. Caused clock to be BIMODAL.
Why are bifurcated animals not affected by jetlag?
Because half of their clock is already there! If they need to adjust to 1 night time, there's much more time to catch up to. If sleep is bimodal, there's not much adjustment needed.
Describe patterns of REM & NREM sleep over time.
REM: Infants get ~8 hrs then rapidly drops off after 1 year to ~4, then 2
NREM: 8 as infant, 9 as child, then rapidly declines in to adolescents and slowly declines into adulthood.
What is the pattern of infant sleep in first yr of life?
Newbord: Sporadic. No rhythm.
At ~4 mos: Sleep mostly at night, awake in day.
What is a Chronotype & what does it look like for the population?
It's a "time type" of either Larks (early bird) or Night owls.
Looks like a normal distribution, with majority of people somewhere in the middle.
What are the sleep trends across gender?
Females go through puberty earlier, so start going to bed late earlier in life.
Males still go to bed later after hitting puberty.
College students average ________ hours of sleep
6.3
Two-Process Model of Sleep
Process S = Sleep debt.
Homeostatic process. Wake up in AM - feel refreshed - Process builds over day - get more tired - accumulates over time.
Process C = Circadian.
Daily clock. Programmed to be less efficient at certain times of the day. Ups & downs in the day.
Interaction b/w them:
The greater distance, the more likely sleep is needed/will come. Circadian wakes you up at the smallest distance
Explain the Two-Process Model of Sleep graph when sleep is deprived
S goes UP & UP
Accumulates additional sleep debt during times where there would normally be sleep.
C does same pattern - in waves
So person experiences lows & highs, still with cognitive impairment
When finally does sleep - sleeps longer to remove debt
Rebound = Sleeping more to make up additional debt
Higher TST = Total Sleep Time
What happened to rats when sleep deprived?
Lost weight, metabolism changed, ulcers.
They died within 11 - 32 days =(
Some symptoms of sleep deprivation in humans (THERE'S MANY!):
Irritability
Cognitive impairment
Memory lapses or loss
Impaired moral judgement
Yawning
Hallucinations
Symptoms similar to ADHD
Immune system
impaired – easier to become sick
Risk of Type 2 diabetes – wt gain
Growth is suppressed – phsychological dwarfism
Risk of obesity
Decreased body temp
Increased risk of heart disease
What happened in the sleep studies with humans in bed for 8, 6 & 4 hours?
Even if in bed for 8 hours - they're not actually sleeping that long (6.5 hrs of sleep). So they had cognitive impairments.
6 hrs in bed = 5.5 actual sleep
4 hrs in bed = 3.5 actual sleep
People in the 4 & 6 hr group UNABLE TO TELL HOW BAD THEY DID! Not sensitive to effects.
Alpha , Beta, Delta waves
Alpha = Small/spiky. Lots of neurons doing lots of things. Relaxed Arousal (8-12 Hz). Baseline activity.
Beta = Attentive Arousal (13 - 30Hz)
Delta = Large and slow. Bunch of neurons in sync to do this pattern.
Sleep Spindles & K Complexes:
Occur in Stage 2 of sleep.
Sleep spindle – hippocampus. Transient bursts. Related to IQ & learning
K complexes – responding to sound
Studies count sleep spindles & k complexes & relate to how well ppl learn & consolidate memories
5. REM. 20 - 25%. Close to light (stage 1) sleep in brain, but muscles relaxed close to deep (stage 4). Occurs every 90 mins. Eyes dart around. REM increases in amount of time, the closer to waking up you get.
Atonia = Lack of muscle control
Why do the eyes dart around during REM?
To get sufficient oxygen to the corneas! They get oxygen directly from the surrounding air. They deteriorate in sleep. While they do get some oxygen from the fluid behind them, it becomes stagnant so moving them increases oxygen supply.
Makes sense b/c it happens at end of sleep cycle when fluid builds up. Other manifestations of REM may be byproduct of the eye movements. Also if you sleep longer you devote more time to REM.
However, medications that restrict REM sleep arent shown to affect peoples corneas.
What are some general trends in the sleep cycle pattern?
Each ~ 90 mins. Beginning cycles you get more deep sleep, in stages 4. That decreases throughout the night to only get to stage 3, as the REM stage increases.
SWS
= Slow Wave Sleep
Stages 3 & 4
Delta waves
Atonia
Muscle "paralysis" during sleep. Usually happens in REM.
Types of Insomnia:
Onset = Could be Circadian rhythm disorder
Maintenance = Anxiety #1 related
Terminal = Up too early. Circadian disorder.
Chronic = Leads to many cognitive & emotional impairments
Fatal Familial = Deadly. Genetic. Due to prion mutation. Die within 18 months.
Causes of Narcolepsy:
Orexin/Hypocretin - NT
Lack hypothalamic cells that produce & release orexin.
Possibly autoimmune reaction - body attacks them?
Dogs lack gene for orexin receptors have narcolepsy.
In humans: Found that receptors were fine, just less to act on receptors. In spine: Normal levels. In brain: none.
CPAP
Continuous Positive Airway Pressure
Used to treat sleep apnea. Keeps airways open so ppl don't stop breathing in sleep.
Structures found to be important during sleep:
Cortex
Basal forebrain
Limbic system
Thalamus
Hypothalamus
Hippocampus
Cerebellum
Pons
Medulla
Reticular Formation & Sleep:
Mid/Hind brain structure
Motor control
"Reticular" = net. neural connections.
Release of AcH (Acetylcholine)- excites cells in the hypothalamus, thalamus, basal forebrain
High during REM (wakefullness), LOW in NREM
Locus Cereleus & Sleep:
Waking activated by norepinephrine
Activity high during wake
Low in REM - suppresses REM sleep
Bursts during emotional arousal
Storage of recent memories & increases wakefulness, when stimulated
(5-HT & Seretonin also low in REM)
True or False: Sleep & hibernation are the same thing.
False.
(Squirrels de-hybernate to sleep)
Basal Forebrain & Sleep
Release Excitatory NT(AcH) - Excites thalamus & cortex for learning, attention, shifts in sleep stages
and
Releases Inhibitory NT (GABA) - inhibiting thalamus & cortex
Definition of Learning:
Change in behavior that results from experience
Definition of Memory:
Retention of changes over time separate from development
Name the 2 types of Declarative memory & what they are involved in:
1. Semantic = Facts
2. Episodic = Autobiographical. Stuff that happened to you.
Name the 4 types of Non-Declarative memory & what they are involved in:
1. Procedural/Skill = Cerebellum, motor cortex, basal ganglia. Include practice; sports, playing instrument, riding bike.
2. Associative = Classical Conditioning. Cerebellum. ex Pavlov's Dogs. Fear Memory = Amygdala. Pairing tone w/shock.
3. Non-Associative = Habituation (repeated stim, LESS sensitive). Sensitization (repeated stim, MORE sensitive).
4. Priming = Using stimulus to affect later behavior.
Describe case study HM (Henry Molaison)
Most studied human amnesia case
Seizures at 16 - Removed parts of medial temporal, hippo, amygdala
He suffered BOTH Anterograde & Retrograde amnesia
He never recalled meeting the people studying him. Would have to be introduced every time
Could learn certain TYPES of memories:
Mirror writing task – Look into mirror next to paper
Write name so it looks correct in mirror. Very hard to do b/c we usually look at paper – must retrain brain
Interesting: He got very good at it, but never remembered practicing/training on it
Anterograde Amnesia
FUTURE: Inability to form NEW memories
Retrograde Amnesia:
Past:
Loss of memories from the past
Going backwards
OFTEN GRATED
– WORSE in more recent past, early past is better
OR COMPLETE
– can't remember ANYTHING from past
HM's most intact memory was for the DISTANT past – Implies:
Those memories are stored OUTSIDE the medial temporal lobe (which is largely what he had removed)
Clive Waring & Memory Loss
British music composer
Herpes encephalitis infection in 1985 left him with Anterograde & Retrograde Amnesia
Remembers his wife, even though they were only married 1 yr before the infection
Writes in journal all the time: "Waking up for the FIRST TIME" with all the other entries crossed out
He knows facts about the world but most past memories wiped out - except for maybe emotional ones.
Risk factors: Age #1, Female more likely, family history, mild cognitive impairment, head trauma earlier in life, genes
Protective factors: Active mind, social engagement, healthy heart & lifestyle, low cholesterol/ non-smoking
Alzheimers & memory: What's going on in the brain? What are the treatments?
Usually not diagnosed until AFTER DEATH
1. Cell death - Brain is usually smaller.
2. Amyloid Plaques - Deposits in cell & tau proteins inside the cells accumulate. Forms Tangles. Found in cortex, hippocampus, basal forebrain, decrease in AcH
Treatments:
Approved Drugs: Cholinestarase which prevent breakdown of AcH. Memantine - NMDA-Receptor antagonist.
Non Approved Drugs: Insulin - Disregulate feeding/body cycle via intranasal spray (to prevent going into blood stream)
The remembering curve over 0 second & 30 second delay shows:
Recall after 0 delay is best for first and most recent events.
Recall after 30 second delay is best for first ONLY.
WHY?
First get list - start consolidating words first. This becomes difficult the more you get. Tested immediately - Words still stored in short term.
Tested later - Later words lost, first get stored in Consolidation.
Visual Learning Task + Sleep
Difficult task of picking out symbols.
Measure if ppl get more or less sensitive over time
People given 12-hr delay with & without sleep
People WITH SLEEP in between training & trails did SIGNIFICANTLY better at retest.
2 Main areas involved in the Eyeblink Reponse:
1. Lateral Interpositus (Nucleus of the Cerebellum)
2. Red Nucleus
What happens to eyeblink responses after the LIP & Red Nucleus recover function? What do these findings say about their functions?
LIP - At first suppressed still - then takes 3-4 sessions to max out.
RN - On first session already at 80%
*This says that LIP involved in learning, & RN involved in expression of learned trait
What is eyeblink classified under in the Learning & Memory model?