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