Sleep & Attention
June 23, 2011
Sleep Architechture
Why Do We Sleep?
• Who knows?!? It’s not entirely clear.
• However, we do know that all organisms,
from fruit flies to humans, show some
form of sleep-like behavior.
• Sleep is ESSENTIAL
– Sleep deprived humans can become paranoid
and have hallucinations.
– Sleep deprived rats can die after 2-3 weeks.
• We do have some ideas…
Proposed functions of sleep
Function
NREM sleep
REM sleep
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Brain or body restoration, or both
Replenishment of cerebral glycogen
Tissue synthesis and cell mitosis
Protein synthesis
Growth hormone release
Thermo regulation
Energy conservation
Regulation of noradrenergic activity
Memory consolidation and information processing
Brain development
Cell maturation
Development of oculomotor control
Programming of genetically determined behaviors
Neural stimulation
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From Lecture at Emory University , 2006
What is Sleep?
Awake State
• Alpha Waves
– Smooth, synchronous activity from 8-12 Hz
– Relaxation
• Beta Waves
– Irregular, desynchronous activity from 13-30 Hz
– Arousal & Wakefulness
http://pn.bmj.com/content/10/5/300.full
Stage 1 & 2 Sleep
• Theta Waves
– 3.5-7.5 Hz EEG activity
– Early slow-wave sleep and REM sleep
• Stage 2 sleep is also characterized by sleep
spindles and K complexes (short bursts of waves
that may help person fall into deeper sleep by
decreasing sensitivity to outer stimuli)
http://pn.bmj.com/content/10/5/300.full
Stage 3 & 4 Sleep
• Delta Activity
– High-amplitude (less than 3.5 Hz)
• Stage 3 consists of approx 20-50% delta activity
• Stage 4 consists of more than 50% delta activity
http://pn.bmj.com/content/10/5/300.full
REM Sleep
• Desynchronized EEG movement
accompanied by Rapid Eye Movement
• 15-30 Hz waves
• Also characterized by inability to move
your muscles (paradoxical sleep)
• This is the stage when dreams occur.
http://healthy-ojas.com/sleep/sleep-stages.html
Sleep Progression and Cycle
http://pn.bmj.com/content/10/5/300.full
Astronaut Sleep Activity
Neurobiology of Sleep
Sleep in the Brain
http://www.hms.harvard.edu/hmni/On_The_Brain/Volume04/Number4/Sleep.html
Ventrolateral Preoptic Area
• Releases GABA to
inhibit wakepromoting regions of
the brain and thereby
promote sleep
– Destruction of the
VLPA causes insomnia
in rats
– Electrical stimulation
causes sleepiness
From Lecture at Emory University , 2006
Sleep Promotion
• Sleep promoting regions in the VLPA release
inhibitory GABA signals to
– Acetylcholine neurons in basal forebrain
– Histaminergic neurons in the tuberomammillary
nucleus
– Hypocretin neurons
– Noreprinephrine neurons in the Locus Ceruleus
– Serotonin in the Dorsal Raphe
• Inhibition of these regions decreases
wakefulness and increases sleepiness
REM Sleep Promotion
• During REM sleep, the ACh and hypocretin
neurons remain active.
• Projections from the Medial Pontine
Reticular Formation activate ACh neurons
in the cerebral cortex to keep them active.
Models of sleep-waking regulation
Waking
Thalamus,Cortex
Hcrt
HA
NE
5-HT
ACh
TM
LC
DR
ACh
Hcrt
From Lecture at Emory University , 2006
Models of sleep-waking regulation
NREM
Waking
sleep
Thalamus,Cortex
Hcrt
HA
NE
5-HT
ACh
TM
LC
DR
ACh
GABA
Hcrt
POA
From Lecture at Emory University , 2006
Models of sleep-waking regulation
REM
Waking
sleep
Thalamus,Cortex
Hcrt
HA
NE
5-HT
ACh
TM
LC
DR
ACh
GABA
Hcrt
POA+PAG
From Lecture at Emory University , 2006
Dream Journal Analysis
Nova Science NOW
http://www.mptv.org/podcasts/show/?p_id=21
Sleepiness Log Analysis
Discussion
• Did you find any rhythms or patterns in
your sleep log?
• What do these rhythms mean?
http://mrbarlow.files.wordpress.com/2010/08/normalsleep.gif
Circadian Rhythms
• Daily 24-hour
•
rhythms in
several
chemicals, like
melatonin, help
control our
sleep/wake
cycles.
Melatonin is
secreted by the
pineal gland.
http://www.endotext.org/neuroendo/neuroendo15/neuroendo15.htm
What Regulates Circadian
Rhythms?
• The Suprachiasmatic
•
Nucleus (SCN) is our
primary biological
clock that organizes
these rhythms.
It does this through
its projections to the
midbrain and
hypothalamic nuclei.
http://people.usd.edu/~cliff/Courses/Behavioral%20Neuroscience/Biorhythm/BRfigs/BRAfferent%20SCN%20figures.html
The Michael Siffre Story
Sleep Difficulties
Sleep Disorder Quiz
1. Do you snore loudly and/or heavily while asleep?
2. Are you excessively sleepy or do you lack energy in the daytime?
3. Do you have trouble with concentration or memory loss?
4. Do you fall asleep while driving, in meetings, while reading a book, or
while watching television?
5. Do you have occasional morning headaches?
6. Do you sleepwalk, have nightmares, or have night terrors?
7. Do you suffer from depression or mood changes?
8. Do you have trouble going to sleep or staying asleep?
9. Have you experienced recent weight gain or high blood pressure?
10. Have you been told you hold your breath when you sleep?
Narcolepsy
• Characterized by suddenly falling asleep at an
•
•
inappropriate time
Cataplexy, a common symptom, involves
complete paralysis during a narcoleptic attack.
Likely caused by activation of REM sleep
promoting brain areas at inappropriate times
– Mutations in the gene responsible for producing
hypocretin are also involved
• Successfully treated by stimulants that increase
serotonergic and noradrenergic activity
Night Terrors
• Terrifying period of screaming, trembling,
and racing heart
• Usually does not remember what caused
the night terror
• Associated with slow-wave sleep
• Most common in children, these
are usually out-grown with age
and do not require treatment
Restless Leg Syndrome
• Insatiable urge to move ones legs in order
to escape a tingling feeling or an “itch you
can’t scratch”
• Can also occur to arms, torso, etc
• Worsens while relaxing and is relieved by
movement or activity
• Dopamine and iron deficiency have been
implicated
Sleep Apnea
• Temporary cessation of
•
•
•
breathing during sleep
Results in daytime
sleepiness and fatigue
May occur when the
muscle paralysis of REM
sleep extends into the
throat muscles
Treatment often includes a
CPAP (continuous positive
airway pressure) machine
to help with breathing
during sleep
http://apnea-and-snoring.com/?p=29
REM without Atonia
• What happens if a person
•
Morrison, A. R., L. D. Sanford, et al. (1995). "Stimuluselicited behavior in rapid eye movement sleep without
atonia." Behavioral neuroscience 109(5): 972-979.
in REM sleep DOESN’T
have muscle paralysis?
Motor cortex and
subcortical motor systems
remain active, and
without the atonia
induced by REM, a person
will be able to wake up
and act out their dreams.
Sample Case
• “I was a halfback playing football, and
after the quarterback reeived the ball from
the center he lateraled it sideways to me
and I’m supposed to go around end and
cut back over tack and—this is very vivid—
as I cut back over tackle there is this big
280-pound tackle waiting, so I, according
to football rules, was to give him my
shoulder and bounce him out of the way…”
Sample Case, Cont’d
• “…When I came to, I was standing in front
of our dresser and I had [gotten up out of
bed and run and] knocked lamps, mirrors,
and everything off the dresser, hit my
head against the wall, and my knee
against the dresser.”
Schenk et al, 1986, p. 294
Why Am I So Sleepy or
Hyper?
Design a Public Service
Announcement
Neurobiology of Attention &
Arousal
http://www.doctorsecrets.com/your-kids/attention-deficit-disorder-symptoms.html
You Are Getting Very Sleepy…
• Remember from this morning: Sleep occurs
when the VLPA is activated and then inhibits:
– Acetylcholine neurons in basal forebrain
– Histaminergic neurons in the tuberomammillary
nucleus
– Hypocretin neurons
– Noreprinephrine neurons in the Locus Ceruleus
– Serotonin in the Dorsal Raphe
• So what do you think might happen when you
need to wake up?
Rise And Shine!
• Stimulation of the Brain Stem Reticular
Formation leads to arousal and a wake
state.
• The reticular formation then follows 2
pathways:
– Dorsal: Projects through the thalamus to the
cerebral cortex
– Ventral: Projects through the lateral
hypothalamus, basal ganglia, and basal
forebrain regions to the cortex &
hippocampus
Anatomy of the arousal
systems
MS
NBM
DR
LDT
DBB
Hcrt
PPT
LC
TM
Histamine, serotonin, norepinephrine, acetylcholine, hypocretin
From Lecture at Emory University , 2006
Reticular Formation and Beyond
• Activation of the Reticular Formation
results in release of:
– Histamine from the tuberomammillary nucleus
(TMN)
– Norepinephrine in the locus ceruleus (LC)
– Serotonin from the dorsal raphe (DR)
– Hypocretin from the Lateral hypothalamic
area (LHA)
• Together, this helps you become awake!
Arousal Systems
- Histamine Waking
NREM sleep
tuberomammillary nucleus (TMN)
c-fos activity
From Lecture at Emory University , 2006
Arousal Systems
- Norepinephrine -
Waking
locus coeruleus (LC)
c-fos activity
From Lecture at Emory University , 2006
Arousal Systems
- Serotonin -
dorsal raphe (DR)
From Lecture at Emory University , 2006
Arousal Systems
- Hypocretin (orexin) -
Waking
Lateral hypothalamic area (LHA)
NREM sleep
c-fos activity
From Lecture at Emory University , 2006
Models of sleep-waking regulation
Waking
Thalamus,Cortex
Hcrt
HA
NE
5-HT
ACh
TM
LC
DR
ACh
Hcrt
From Lecture at Emory University , 2006
The Results Are In!
Hyperactivity and Behavioral
Disorders
http://offthemark.com/search-results/key/hyperactive/
Attention Deficit & Hyperactivity
Disorder
• Excess hyperactivity and inability to pay
attention beyond that expected for one’s
developmental stage
• Medications typically target norepinephrine
and/or dopamine levels
– Should they increase or decrease these
levels?
– DA may help to decrease inappropriate
network signals and NE may increase
appropriate ones.
• How Do These
Pathways
Compare to
Sleep/Wake?
Neurobiology of Attention
Deficit/Hyperactivity Disorder
PURPER-OUAKIL, DIANE; RAMOZ,
NICOLAS; LEPAGNOL-BESTEL,
AUDE-MARIE; GORWOOD, PHILIP;
SIMONNEAU, MICHEL. Pediatric
Research. 69(5 Part 2):69R-76R,
May 2011. doi:
10.1203/PDR.0b013e318212b40f
Conduct Disorder
• Persistent behaviors that violate the basic rights
•
of others or societal conventions of behavior
May include:
– Aggressive behaviors that threaten the well being of
others
– Vandalism, arson, or related property-damaging
behaviors
– Lying or stealing
– Serious rule violations, skipping school, running away,
etc.
• Linked with decreased temporal lobe volume and
decreased serotonin levels
Oppositional-Defiant Disorder
• Repeated pattern of defiant and rebellious
behavior, which may include:
– Frequent temper tantrums
– Spiteful, mean behavior and revenge attempts
– Resentment and hateful talking
– Highly argumentative
• Possible alterations in serotonin,
differences in genes for dopaminergic and
noradrenergic signaling
Attention Experiments
http://www.bmj.com/content/316/7144/1594.full
Find the two Ts
http://www.psychologytoday.com/blog/the-object-attention/201009/why-are-dead-elephants-easy-find
Find the Red T
http://www.psychologytoday.com/blog/the-object-attention/201009/why-are-dead-elephants-easy-find
Find the tilted line on the left,
vertical on the right
http://www.psychologytoday.com/blog/the-object-attention/201009/why-are-dead-elephants-easy-find