NSCI 175: Brain Rhythms and Sleep
After ___ hours of being awake, you will start to feel sleepy
16
In stage __ you have spindle and K complex
2
How long may REM sleep periods last?
30-50 minutes
Serotonin and NE enhance ____
5-HT & NE neurons fire during & enhance wake; Different ACh neurons enhance REM sleep while others enhance awake states
Normal night we cycle through the stages of non REM and REM, repeating every
90 minutes
Which of the following represents delta rhythms, the hallmark of deep sleep? Greater than 14 Hz 4-7 Hz 8-13 Hz Less than 4 Hz
???
Increased Tau buildup causes
Alzheimer's, since sleep deprivation causes lack of filtering the brain
Why is REM sleep referred to as paradoxical sleep? A. Vivid, detailed illusions called dreams are conjured during REM sleep B. The EEG for REM sleep is almost indistinguishable from an active, waking brain C. Rapid eye movements occur during REM sleep D. The body (except for the eyes and respiratory muscles) is immobilized
B. The EEG for REM sleep is almost indistinguishable from an active, waking brain
What brain regions and associated neurotransmitters are implicated in changes associated with awakening and states of arousal? A. Brain stem and forebrain (acetylcholine) B. Raphe nuclei (serotonin) C. All choices are correct. D. Locus coeruleus (norepinephrine)
C. All choices are correct.
Brain Plasticity Theory
Changes in structure and organization of brain when we sleep. Rerouting the neural circut
What do modulatory systems do to our motor neurons
Descending branches of these systems inhibit motor neurons during dreaming!
Which of the following describes REM sleep behavior disorder? Dreamers with delta wave terrors Sleepers who do not generate REM brain waves characteristic of REM sleep Dreamers have no REM atonia and therefore may act out their dreams. Sleepers who have narcolepsy
Dreamers have no REM atonia and therefore may act out their dreams.
Increased firing rates in which of the following systems likely support the transition from sleep to wake? Select all that apply.
Histamine Norepinephrine Acetylcholine Seritonin
Inactivity Theory
Inactivity at night served as survival function to hide from predators
Awake EEG
Low voltage Fast Vivid Externally generated Logic progressive continuous voluntary REM: often
REM Sleep EEG
Low voltage Fast vivid illogical bizarre muscle paralysis
EEG
Measure of multiple cerebral pyramidal neurons helps detect patterns in circadian rhythm through an electrodes
Delta rythmns
Non REM
Kidney function slows, parasympathetic, sleep spindle, K complex, four stages, reduced muscle tension
Non REM sleep
Atonia, paradoxical sleep and sympathetic activation. fast low amplitudes, beta and gamma rhythms
REM sleep
beta and gamma rhythms
REM sleep
Fatal Familial Insomnia (FFI)
Rare genetic disorder- Inability to sleep (starts off mild), but progressively worsens leading to significant physical and mental deterioration- Abnormal variant in the prio-related protein (PRNP) located in the thalamus- Prognosis: Death within 6-36 months after the onset of symptoms (no cure): spasms, can't eat, fever, rapid heart rate Episodes of hallucinations.
Why we sleep and consequence of sleep deprivation
Restoration: sleep to rest and recovery Adaptation: hide from predators Memory consolidation, prevents cognitive impairments
Restorative Theory
Restore elements impaired and depleted while awake
What do modulatory systems do to thalamus in sleep cycle
Systems control the rhythmic firing of thalamus which controls EEG rhythms of cortex (slow rhythms of sleep in thalamus block sensory information from reaching the cortex!)
What brain structure is known to act as a powerful pacemaker for the cerebral cortex? Brain stem Thalamus Midbrain Cerebellum
Thalamus
Four stages of non REM sleep
Transitional sleep (few minutes & lightest) Slightly deeper (5-15 minutes)sleep spindles & K complex Delta rhythms, deeper sleep Deepest sleep (20-40 min)Slow large amplitude delta waves
The suprachiasmatic nucleus of the thalamus requires input from the retina to maintain circadian rhythms that are in phase with the day-night cycle. False True
True
Hypocretin
a neurotransmitter secreted by cells in the hypothalamus; helps regulate sleep-wake cycles
Shorter sleep predicts
a shorter life because of diseases associated
Sleep deprived individuals have increased activity in the ___
amygdala
REM on-cells
are cholinergic neurons in the pons that fire to enhance REM events
Orexin
can excite neurons in modulatory systems PROMOTES WAKEFULNESS: inhibit REM sleep
Melatonin is released when
darkness rises
As we age our REM sleep and sleep
decreases
Stages 3 and 4 have ____ rhythms
delta
What part of the nervous system generates the fluctuations and oscillations of an EEG
dendrites of many pyramidal neurons in the cerebral cortex
Zeitgebers:
environmental cues that signals the passage of time For mammals: primarily light-dark cycle
Major connection in sleep between the __ and the __
excitatory: hypothalamus and the cerebral cortex
Melatonin
helps time when sleep will occur. It does not help when sleep occurs. Helpful for jet lag.
Deep non REM sleep amplitude and frequency
high amp, low frequency
Non REM sleep EEG
high voltage, slow involuntary
suprachiasmatic nuclei (SCN)
in hypothalamus that function as a biological clock
REM off-cells
include norepinephrine neurons in the locus coeruleus and serotonergic neurons in the raphe nuclei which decrease firing to almost nothing during REM
Caffeine
inhibits sleep signal. Latches to adenosine sites and masks the receptors. Once caffeine wears off, adenosine has build up
consequence of sleep deprivation
irritibility, emotional instability increased heart rate episodes of disorientation
Awake amplitude and frequncy
low amplitude and high frequency rhythms
Hypocretin is involved in
narcolepsy
Circadian rhythm vs ultradian rhythm
over 24 hours versus over a few minutes
The time that elapses between two successive occurrences of a circadian event, such as the commencement of the day's activities, is called the zeitgeber period entrainment phase
period
suprachiasmatic nuclei (SCN) receives input from
photosensitive retinal ganglion cells, which allows them to reset the circadian clock
Anti-Histamine promotes
promotes sleep
Babies will sleep more for shorter periods with more __
rem cycle
Transplanting a SCN into a lesioned animal
restores circadian rhythms
Stimulating the SCN
shifts the circadian rhythms
Energy Conservation Theory
sleep is an adaptation that allows us to conserve energy for gathering food, defeating predators
Lesions to the SCN abolishes
the circadian rhythms
Which of the following has not been found to demonstrate a circadian rhythm? body temperature they all demonstrate a circadian rhythm hair growth hormone secretion
they all demonstrate a circadian rhythm
narcolepsy is
when you dont go through slow wave sleep before REM, Makes you sleepy in the day
The external cue that animals use to discern the time of day is called a
zeitgeber