EEG and sleep Flashcards
Where is the main clock of the body located?
suprachiasmatic nucleus (SCN) of hypothalamus
2 Genes that create the circadian rhythm by increasing transcription and translation of other genes in the SCN
- Clock (CLK)
- BMAL1
What time of day does BMAL increase?
night
What genes do BMAL1 and CLK increase which then feedback and inhibit BMAL1 and CLK
- Period (per 1-3)
- Cryptochrome gene (Cry 1 and 2)
When an individual has a stongly set circadian rhythm that is off then what gene is mutated?
clock
On its own, the SCN creates a day that is how long
25 hours
What tract helps us match our activity with Daytime
retino-hypothalamic tract
Does the retino-hypothalamic tract use the visual cortex?
NO
What neurotransmitter is released in the hypothalamus due to DAYTIME from the retino-hypothalamic tract (ENTRAINMENT)?
Night?
Glutamate
melatonin
EEG when awake
low amplitude high frequency
what happens to EEG when first go to sleep
amplitude initially goes even lower than when awake and then it also starts to slow down
what happens to EEG as you have been asleep for a while
Larger amplitude and much slower
Dreams that are boring and rehashing the events of the day
non-REM
EEG of REM sleep
low amplitude high frequency. very much like wakefulness
Vivid dreams that don’t really happen
REM sleep
Homeostatic need for sleep triggers what type of sleep?
NREM
circadian clock itself triggers what type of sleep?
REM
What area of hypothalmus is crucial for sleep induction
ventral preoptic area (VPO)
homeostatic need for sleep is tied to accumulation of what?
adenosine
what in the blood leads to an increase in adenosine in CSF
PGD2
What receptor in VPO binds adensine?
A2a
What things other than adenosine trigger tiredness in the VPO?
- IL-1b and TNF-alpha (SICK)
- GHRH (growing)
pathway of sleepiness in the VPO triggered by IL-1, TNF, and GHRH?
NF-kappa-b –> NO synthase –>NO
part of brain responsible for initiation of REM sleep
lateral pontine tegmentum
_______ neurons from the lateral pontine tegmentum release ______ in the _____?
cholinergic
Ach
Geniculate body
After stimulation from the lateral pontine tegmentum, the geniculate body then sends input where?
occipital cortex
What causes muscle paralysis during REM sleep?
Locus ceruleus sends inhibitory input to alpha-motorneurons
What muscles are spared by the paralysis causes by locus ceruleus?
diaphragm and small muscle groups
the _____ induces arousal by releasing ______.
These then travel to the ______ which releases ______.
This then travels to the ______ which releases _______ and suppresses REM sleep.
lateral hypothalamus
Orexin A and B (hypocretin 1 and 2)
tuberomamillary nucleus
Histamine
Locus ceruleus
Norepinephrine
If you see a general or repeated pattern in an EEG then what is often going on?
a pathological process
alpha waves
low amplitude (50) high frequency (8-13hz)
quiet wakefulness (thinking) with eyes CLOSED
alpha
area of prevalence of Alpha waves
occipital cortex
when do alpha waves disappear
sleep
what do alpha waves require?
connection b/t thalamus and cortex (basically awake)
Beta waves
lower amplitude (<50) higher frequency (14-80-Hz)
occur during alert wakefulness. eyes OPEN
Beta waves
What happens when you open your eyes but you have been awake the whole time?
Alpha block or alerting response. beta waves begin
where are beta waves most prevalent
frontal cortex
When would you likely see gamma waves?
if you are planning a motor response
What part of the brain may the gamma waves require?
hippocampus
Theta waves
big (100)
slow (4-7 Hz)
Theta waves in children?
Adults?
normal
frustration and disappointment
Also occur during sleep
what part of brain for theta waves?
hippocampus
Delta waves
Biggest (100-200)
Slowest (<3.5 Hz)
When are Delta waves seen?
Deep sleep and in infants
if you see Delta waves during wakefulness then what is happening?
Serious organic brain disease . . maybe vegetative state
Do Delta waves need connection between thalamus and cortex?
NO
What can decrease frequency of alpha rhythm?
- hypoglycemia
- Low body temp
- Low adrenal glucocorticoids
- high PaCO2
First sleep cycle at night
70-100 minutes short REM
Later sleep cycles at night
90 minutes but less time in Deep sleep and more in REM
Describe the sleep cycle in children
more time in REM, deep sleep, and total sleep time
sleep cycle in elderly
-fewer REM episodes
-almost NO deep sleep
-more frequent awakenings
-less total sleep time but more likely to nap
-
When are sleep spindles most prominent
N2
K complexes
N2
What type of sleep do you wake up from?
REM
