Lecture 09 Sleep

non_REM (NREM)

- Makes up about 80% of sleep

- three stages

- heart rate and breathing slow

- no dreams

Rapid eye movement (REM)

- Makes up about 20% of sleep

- heart rate and breathing increase

- Dreams

- Muscle paralysis

What is the typical period between REM cycles?

90-110 minutes, for 7-8 hours of sleep you expect 4-5 cycles

Electroencephalogram (EEG)

Electrodes across the scalp to record bulk electrical activity from brain (indirect)

What is the resolution for an EEG and what is it used for?

High temporal, low spatial resolution. Used to identify seizures.

Beta

15-20 cycles per second

Alpha

8-12 cycles per second (Hertz)

Delta

1 cycle per second

Wake

dominated by beta

Stage 1

characterized by alpha

Stage 2

sleep spindles appear

Stage 3 (slow wave sleep)

Delta waves

REM

beta

What type of sleep decreases with age?

REM sleep and total sleep

Sleep deprivation

Compromises immune function, unable to develop an immune response, stress, and death

What increases by trying to "make up" sleep deprivation?

Total time asleep in stage 3 and REM was more intense

What are the effects of alcohol and sleep?

Decreases the time it takes to get to sleep, reduces or prevents REM, poorer sleep quality, and detrimental

Forebrain

Region that can display slow-wave sleep (SWS)

Brainstem

Activates the forebrain into wakefulness

Pontine

Triggers REM sleep

Hypothalamic

Affects the other 3 (forebrain, brainstem, pontine) to determine what state the brain will be in

Transections of the brain showed an isolated forebrain was locked in a state of near permanent slow-wave sleep are due to...

the basal forebrain

and the preoptic area

What are the reticular formation's neurons in charge of?

Wakefullness

Neurons in the basal forebrain and preoptic area project into where?

Tuberomamillary nucleus where they release GABA and cause slow wave sleep.

What happens if electrical stimulation is applied to the reticular formation?

Wakes animals up from sleep

What happens you lesion the reticular formation?

Produce persistent sleep

What does the reticular formation inhibit?

The basal forebrain neurons

What do lesions in the pons do?

Abolish REM sleep

What would happen if you apply electrical stimulation to the pons?

Extend REM sleep

Subcoeruleus

A small region in the pons where there are neurons active only during REM

Narcolepsy

People and animals transition from being away

What is narcolepsy driven by?

The death of or mutation in the cells that make hypocretin/orexin

Hypocretin/orexin

Neuropeptide made by a small population of neurons in the hypothalamus

What are the dominant theories of sleep?

Restoration, survival, learning. Mysterious purpose.