Final Exam: Neuro: Sleep/ Week Cycles

Front 1

What is an EEG?

1) Beta?
2) Alpha?
3) Theta?
4) Delta?

Back 1

An EEG is an ELECTROENCEPHALOGRAM that records the brain electrical potentials from the scalp.

1) Beta - >12 Hz.
2) Alpha - 7 to 12 Hz.
3) Theta - 3 to 7 Hz.
4) Delta - < 3 Hz.

* Note: Sleep recordings represent a continuum of frewuencies.

Front 2

What is the pathway related to sleep?

Back 2

Pathway in brain.

Front 3

What are different characteristics of EEG (high/ low or fast/ slow) in different stages of sleep?

1) Wake?
2) NREM?
3) REM?

Back 3

1) Wake - Low voltage fast EEG
“Desynchronized” - external activation

2) NREM - High voltage slow EEG
“Synchronized” - deactivated

3) REM - Low voltage fast EEG
“Desynchronized” - internal activation

Front 4

*NREM*

What are the different stages in REM sleep and what characterizes these different stages? (4)

STAGE 1?

Back 4

STAGE 1 is characterized by..

1) "Alpha drop- out" - theta activity
2) Vertex sharp waves
3) Slow eye movements
4) Muscle Relaxation
5) Sleep "starts"
6) Central apneas?

Front 5

What are the characteristics of STAGE 2?

Back 5

STAGE 2:

1) Theta activity - progressive slowing
2) Sleep spindles - 13- 14 hz** this is the hallmark of STAGE 2 sleep
3) K- complex - large amplitute/ biphasic/ evoked response

Front 6

What are the characteristics of STAGE 3/4?

Back 6

STAGE 3/4:

1) >20% slow wave activity
2) Frequency and amplitude criteria
3) Highest arousal threshold of sleep
4) Alpha-delta sleep anomaly

Front 7

*REM*

What are the characteristics of REM sleep?

**What's significant about REM sleep?

Back 7

REM sleep:

1) Reticular activation - desynchronization
2) Stage 1- like EEG/ "sawtooth" waves
3) Hippocampal theta activity
4 Phasic/ tonic components
5) Rapid eye movements

6) Muscle atonia
7) Muscle twitches (phasic phenomenon)
8) Cognitive activity
9) PGO (Pontine- Geniculate- Occipital) spikes

** It's has very high levels of COGNITION and INTERNAL activation??

Front 8

When does REM occur most frequently?

Back 8

It occurs most frequently during the second half of the night.

Front 9

WHAT IS THE DIFFERENT BETWEEN SLEEP TERRORS AND NIGHTMARES?

Back 9

**

Front 10

What's the difference between NON-REM and REM sleep?

*NON-REM*
Autonomic activity
Respiratory
Thermal
Muscle tone
Genitals
Cerebral blood flow
Cognition/ Cortical arousal

Back 10

NON-REM

Autonomic activity - decreased heart rate and bp

Respiratory - decreased drive to low O2/ increased CO2

Thermal - intact regulation

Muscle tone - reduced

Genitals -
Cerebral blood flow - reduced CBF

Cognition/ Cortical arousal - reduced

Front 11

*REM*

Back 11

REM

Autonomic activity - variable sympathetic activity

Respiratory - lowest drive to low 02/ increased C02

Thermal - poikilothermic

Muscle tone - minimal

Genitals - penil erections/ increased vaginal blood flow

Cerebral blood flow - increased CBF

Cognition/ Cortical arousal - abundant BIZARRE

Front 12

What is the ONTOGENY (development) of sleep?

What are the different stages of development of sleep?

Back 12

1) Fetal sleep
2) Newborns
3) Develop
4) 1 year old
5) 2 years old
6) Second decade
7) Later in adult life
8) Elderly

Front 13

What happens throughout development? (1- 5)

Back 13

1) Fetal sleep - 80% of "active sleep" at 30 weeks

2) Newborns - 16 to 18 hours of sleep
- active sleep 50% of the time
- quiet sleep
- intermediate sleep

3) Develop - establish major nocturnal sleep by 3- 4 months

4) 1 year old - get 12- 13 hours + 2 naps
- 30% of their sleep is in REM

5) 2 years old - get 10- 12 hours of sleep + nap(s)
- only 25% REM (fixed)

Front 14

What happens throughout development? (6-8)

Back 14

6) Second decade - marked by decline of SW activity

7) Later in adult life - gradual decline in SWS but other stages remain fixed

8) Elderly
- an increased in difficulty of staying asleep
- lighter sleep
- increasing awakening
- less refreshing
- changes in timing/ depth/ melatonin secretion

Front 15

*CIRCADIAN RHYTHM*

1) What is sleep- wake cycle?

2) What is it regulated by?

3) What other physiological functions are synchronous with S/W cycle?

Back 15

1) The Sleep wake cycle consists of ~ 24 hours


2) It's regulated by
A) Biological factors
B) External cues (aka ZEITGEBERS)

3) Temperature/ hormonal/ other physiological function in synchrony with S/W cycles

Front 16

1) What is Process S?

2) What is Process C?

Back 16

1) Process S
- It's homeostatic and is related to time since last sleep
- Increases exponentially during wake hours
- Strongly correlated with SWS
- Possibly ADENOSINE driven

2) Process C
- It's a CIRCADIAN- SINUSOIDAL variation of sleep tendency based on temporal schedule

Front 17

What does ENTRAINMENT refer to in terms of CR?

What does adjustments of each cycle period compensate for?

What does synchronization lead to?

Back 17

ENTRAINMENT describes period and phase control of an oscillator by an environmental cycle

- ADJUSTMENTS of each cycle period COMPENSATE for differences between intrinsic period and environmental cycle (day- night)

- You get SYNCHRONIZATION of clocks so that overt rhythms occur at correct daily phases

Front 18

What does FREE- RUNNING refer to?

Back 18

FREE- RUNNING refers to persistence of rhythms during constant conditions (ie constant light or darkness)

- So if humans had a FREE- RUNNING sleep period, it would show an average period slightly longer than 24 hours

Front 19

1) When are S-W rhythms established?

2) What do FREE- RUNNING data show?

3) What about Periodocity?

Back 19

1) S-W cycles are established early in life

2) FREE- RUNNING data suggests a period of 25.5 hours with significant variability AND evidence suggests that we have a pacemaker period of about 24.2 hours with little variance

3) Periodocity appears to be stable of a life cycle although expression may vary

Front 20

What is PHOTIC ENTRAINMENT? (5)

Back 20

PHOTIC ENTRAINMENT

1) It is when the light entrains the CR within various limis and according to specific patterns

2) Graphic description of the cycles response to light is contained in phase- response curves (PRC)

3) Light presented near INITIATION of "dark cycle activity" produces PHASE DELAY

4) Light presented near CONCLUSION of "dark cycle activity" produces PHASE ADVANCE

5) Light presented during typical "light cycle activity" produces little or no effect

Front 21

What things are involved in BIOLOGIC CONTROL?

What controls our PRIMARY CLOCK MECHANISM?

What experimental evidence shows this?

Back 21

BIOLOGIC CONTROL

1) Intrinsic/ self- sustaining/ self- cycling clock mechanism

2) Controls RHYTHMICITY of multiple biological functions and behaviors, including sleep- wake or rest activity

3)PRIMARY CLOCK MECHANISM: SUPRACHIASMATIC NUCLEUS of the HYPOTHALAMUS

4) SCN ablation - >loss of rhythmicity
SCN isolation - > autorhythmicity
SCN stimulation - > phase shifting

Front 22

1) What is the MASTER or GATING PACEMAKER for other oscillators?

2) What does DESYNCHRONIZATION OF RHYTHMS in humans suggest?

Back 22

1) SCN

* some rhythms may survive SCN destruction

2) Desynchroniation of rhythms in humans suggest more than one pacemaker (SEE SLIDE 51)

Front 23

Where is RHYTHMICITY evident?

Back 23

RHYTHMICITY is evident in temperature, hormone secretion, cardio- vascular function, and other systems

Front 24

*MELATONIN*

1) What is it?

2) What is it released by?

3) What does it do?

4) What is it linked to?

Back 24

1) It is the "hormone of darkness"

2) Released by PINEAL GLAND in response to darkness

3) It reinforces "darkness signal" via melatonin receptors on SCN and induces phase shift opposite to those of light

4) It is linked to control of body temp

Front 25

What role might this play in old age and what are some therapeutic actions?

Back 25

Levels decline from childhood to adulthood, especially during old age

May play a role in geriatric insomnia

Some therapeutic actions:
- phase shifting
- reproductive control
- sleep- promotion - role as "hypnotic"
- potential side effects

Front 26

1) What is PHASE- SHIFTING in relation to MELATONIN?

2) What are some sleep promoting effects?

Back 26

PHASE SHIFTING

1) It has potential utility as a treatment for sleep- wake schedule disorders

2) Sleep- promoting effects involve large doses of melatonin and produce sedation

- has been successful in treating elderly with insomnia- - because have low levels of melatonin

- difficult to separate effects from phase- shifting properties

Front 27

What are a few sleep disorders to consider?

Back 27

!) DELAYED SLEEP APNEA
2) ADVANCED SLEEP PHASE
3) BLINDNESS
4) DEVELOPMENTALLY DISABLED
5) SHIFT WORK
6) IRREGULAR SLEEP- WAKE RHYTHM
7) NON-24 HOUR SLEEP- WAKE RHYTHM

Front 28

What are SLEEP WAKE DISORDERS?

Back 28

SLEEP WAKE CYCLES are when one's sleep is out of phase with conventional sleep- wake times or out of phase with other elements of the CR

- causes sleep disturbance

Front 29

What are characteristics of DELAYED SLEEP PHASE SYNDROME? (5)

Back 29

1) Inability to fall asleep at desired / appropriate times

2) Inability to arise at desired / appropriate times

3) Normal sleep on ad lib schedule

4) More commonly seen in younger age groups

5) Social and occupational disturbance

Front 30

What may cause DSPS? (5)

Back 30

1) Age-related change in circadian oscillator (?)

2) Change in interaction of oscillator / entrainment with sleep homeostatic processes

3) Behavioral

4) Psychopathology / depression

5) Limits of phase advancement

Front 31

What are some treatments for DSPS?

Back 31

1) Schedule change?

2) Phototheraphy
- bright light in early morning

3) Melatonin
- administer during early evening

Front 32

* NEUROCHEMISTRY/ ANATOMY *

Back 32

*

Front 33

Where does SENSORY in put for WAKE cycle come from?

What neurons show high firing rates while you are awake?

Back 33

Sensory input - >reticular formation

1) Cholinergic neurons of lateral dorsal tegmentum(LDT) and pedunculopontine tegmentum (PPT) show high firing rates during wake

2) Noradrenergic cells of locus coeruleus show higher firing rates during wake

Front 34

What is the pathway for WAKE CYCLE?

What is the ASCENDING RETICULAR SYSTEM? (SEE SLIDE 68)

Back 34

Ascending reticular activating system (ARAS) projects to thalamus/ hypothalamus/ basal forebrain cortex, producing desynchronization

Front 35

What is the function of OREXIN in the WAKE cycle?

Back 35

*

Front 36

What happens in the brain during NREM sleep generation? (6)

Back 36

1) Ventrolateral preoptic area (GABA) active

2) Reduced firing of ARAS

3) Sensory input blocked at thalamus

4) Spindle production - reticular thalamic nuclei

5) Slow-wave production - thalamus / cortex

6) Decreased firing rate of LC and raphe neurons (5HT)

Front 37

What happens during REM sleep generation?

Back 37

1) Marked drop-out of neuronal firing from locus coeruleus (NE) and raphe neurons (5HT)

2) “REM-on” cells of pontine nuclei - increased firing of LDT and PPT neurons

3) Generation of PGO spikes

4) Descending motor inhibition

Front 38

What are a few WAKE- PROMOTING SUBSTANCES? (6)

Back 38

1) Acetylcholine
2) Norepinephrine
3) Histamine
4) Dopamine
5) Serotonin (?)
6) Orexin (?)

Front 39

What are a few SLEEP- PROMOTING SUBSTANCES? (4)

Back 39

1) Gamma-aminobutyric acid (GABA)
- Major inhibitory transmitter

2) Adenosine

3) Endorphins - sensory information

4) Cholecystokinin - gut

Front 40

What is the function of ADENOSINE? (5)

Back 40

1) Adenosine inhibits basal forebrain ACh neurons

2) Consistently high concentrations in wake

3) Declining concentrations in SWS

4) Specificity to basal forebrain site questioned

5) Concentrations a function of cellular metabolic activity

Front 41

What is CAFFEINE?

Back 41

Caffeine, major adenosine inhibitor, and therefore inhibits the homeostatic promotion of sleep by adenosine, higher doses interferes with sleep and shuts sleep off after a period of time altogether

Front 42

* SLEEP FUNCTION *

Back 42

*

Front 43

NREM

1) How do you restore NREM? (6)

Back 43

A) RESTORE
1) Maintenance of alertness / function

2) Rebound (nREM/REM) after sleep deprivation

3) Increased secretion of anabolic steroids in sleep

4) Decreased secretion of catabolic steroids

5) Tissue repair / restoration (fibromyalgia)

6) Decline in physiologic functions

B) CONSERVE

C) PROTECTIVE STATE

Front 44

2) What can REM sleep help you with? (6)

Back 44

1) Learning / memory
2) Memory purging
3) Promotion of development in young
4) Maintenance of circuitry
5) Restoration of NE transmitter function
- Locus coeruleus
6) Vigilance

Front 45

3) How much sleep do you neeD?

Back 45

Sleep need varies from one person to the next

Front 46

4) How does sleep play a role in MEMORY FUNCTION?

Back 46

Memory function (SWS)

1) Spatial learning paradigm shows firing rates of co-active cells increase in SWS following task acquisition

2) Pattern suggests “playback” feature from hippocampal to cortex may be involved in learning

3) REM deprivation following perceptual learning task abolishes performance gain

4) Previously learned information unaffected

5) SWS disruption produces no interference

6) Possible role of acetylcholine tracts in memory consolidation

Front 47

How might partial sleep deprivation affect you?

Back 47

Vigilance decreases with 1 night of 3 hr or 2 nights of 5 hours of sleep (Wilkinson, 1968)

As sleep restriction proceeds beyond 1-2 nights, cumulative effects are seen

Front 48

What might people who exp sleep deprivation be at risk for?

Who does this apply to?

Back 48

Persons who experience limited sleep durations may be at risk for developing cumulative waking neurobehavioral deficits.

May apply to nightshift workers, medical personnel, sleep apnea patients, etc…

Front 49

* NOTE: sleep loss is cumulative

Back 49

*