Sleep Flashcards
Why do we sleep: Most recent theory, one coloumbo likes
memory consolidation
EEG bands: How big a signal is/how many neurons?
Amplitude/power
EEG bands: how do neurons fire?
Frequency [Hz or cycles/sec]
Waking
Desynchronized, beta activity (high frequency, low amp)
Stage 1
Synchronized
Alpha - relax
Vertex spikes- sharp waves, indicate sleep onset
Slow heart rate, down muscle tension
Stage 2
Sleep spindles- small by condensed activity (high frequency)
K complexes- large gaps, slightly higher amp to transition to stage 3
If awakened during stages 1 or 2
deny asleep
Stage 3
SWS
Large amp, slow wave
Delta waves- high amp, low frequency
Synchronized
REM
Muscle relax
EEG like waking
High amp, high frequency
Delta
High amplitude
0.5-3 Hz
Stage 3 an SWS
Beta
Low amplitude
13-30 Hz
Waking
Gamma
30-100 Hz, very fast
Alzheimer’s connection
Sleep Spindles
Low Amplitude
12-14 Hz
Periodic bursts in stage 2
Alpha
Low amp
8-12 Hz
Stage 1/relaxed
Theta
4-7 Hz
Memory
What measures muscle tension?
Electromyography (EMG)
gone during REM, highest when awake
What measures Eye movement?
EOG: electrooculography
EEG shows that during NREM
synchronized brain waves
sensation and perception throughout sleep
Wake- external, present
NREM- absent
REM- internal, present
Thought throughout sleep
Wake- logical, progressive
NREM- logical, preservative
REM- illogical, bizarre
Movement throughout sleep
Wake- Continuous voluntary
NREM- Episodic involuntary
REM- commanded but inhibited
When does recuperation occur?
NREM, growth hormone secretion
Jenkins/Dallebbach’s odor memory task
Location of objects in computer game while exposed to odor. Expose to odor during REM, SWS, and waking.
SWS for memory consolidation around delta/theta.
All general anesthetics increase ____ receptor signaling by acting as noncompetitive agonists.
GABA-A
Produce slow EEGs that look like SWS
Sleep deprivation recovery trends
First night: more stage 3 sleep
Second night: greater REM intensity
Basal Forebrain
SWS by GABA release
Stimulation: animals sleepy
Lesion: Insomnia
Induces sleep
Reticular Formation
Activates forebrain into wake state
Stimulation: Wake/alert
Lesion: Constant sleep
Located in brainstem
Subcoeruleus (Pons)
REM, inhibits motor neurons
Stimulation/cholinergic agonists: Prolong REM
Lesion: abolish REM
Hypothalamus
Affects other regions, decides sleep/wake
Hypocretin NT, loss = narcolepsy, loss of muscle control
Cycling function: SWS vs. REM
Bremmer’s isolations
cut below medulla - expected, SLEEP NOT DUE TO LACK OF INPUT
Midbrain transection- constant SWS, REM lower than midbrain.
Current theorist say REM dream content is from
recent activity
Theory: Restorative
Growth hormone during stages 3 and 4, gets rid of waste
Weak support, active people don’t need more sleep
Theory: Conservation
SWS, use less energy when sleep
REM doesn’t
Rhythms that occur 1+ x per day (ex: eating)
Ultradian
Rhythms that occur less than 1x per day (ex: going to biopsych)
Infradian
Erb Zucker’s experiment
Activity wheel on tracker
No light cues, cycle stays, but shifts a bit earlier
Where?: SCN
Evidence?
1. Lesions = random cycling
2. SCN in cell culture- vasopression release follows cycle
3. Tau gene rats- shorter cycles, animals match free running activity of donor SCN. Even if surrounded by polymer.
4. Squirrel monkey recordings
How does the SCN get light info
Retinohypothalamic pathway
Retina goes to lateral geniculate nucleus, second projection to V1
TEST QUESTION: Cut off retina to SCN, can you entrain light?
No light entrainment, rhythm stays but is free running
TEST QUESTION: Cut off geniculate/V1, can you still entrain light?
Yes
Retinal ganglion cell’s special pigment
melanopsin, most sensitive to blue light
Pathway of SCN making rhythm
- Clock/cycle (aka Bmal1) make heterodimer
- Bind to promoters to genes per and cry
- Proteins Per and Cry
- Per and Cry come together (dimerize)
- Dimer inhibits gene expression
- Proteins naturally degraded by enzymes
How is cycle entrained to light? Glutamate from retinal hypothalamic pathway that activates per production.
Block Glutamate, free running.
How does SCN work if all cells different?
Electrical synapses between cells
KO Clock gene
Still normal rhythm with light, so either homodimer regulates it, or in it’s absence, glutamate can make up for it.
Rhythm with light cues, but not without?
___ is replenished during sleep
___ low during sleep, peaks midday
Cortisol
Potassium
(Alertness low during sleep)
__ spikes during SWS
__ has huge drop during sleep
Growth hormone
Temp
Discussion Circannual rhythm
Siberian hamster- change color for winter, due to light not just temp.
Not SCN, but don’t know what thanks to Dr. Coloumbo
