Sleep Flashcards
What are the locations most involved with the awake state?
hypothalamus, reticular activating system, and the basal forebrain/nucleus basalis of meynert
What neurotransmitters/locations of the hypothalamus are important for the awake state?
Histamine released from the posterior hypothalamus and projecting widely
hypocretin 1 and 2 from the lateral hypothalamus and projecting broadly
glutamate from posterior hypothalamus
What are the important locations and neurotransmitters of the reticular activating system that are important for the awake state?
location: locus ceruleus
NE is primary neurotransmitter, but glutamate too
What are the important structures and neurotransmitter associated with the basal forebrain in the awake state?
ACh goes to the cortex. input from RAS and posterior hypothalamus that is suppressed by adenosine and GABA during sleep
What areas are most important for non-REM sleep?
anterior hypothalamus- suprachiasmatic nucleus
Raphe nuclei
reticular nucleus of the thalamus
How is the anterior hypothalamus involved in non-REM sleep? Where does it go? What are its affects? Important neurotransmitters?
suprachiasmatic nucleus, which gets info from the retina about the “diurnal fluctuation of ambient light”
GABAergic neurons project to prosterior hypothalamus. GABA effects enhanced by melatonin.
Suprachiasmatic nucleus also projects to the reticular activating system. Inhibits the locus cereuleus and disinhibits the raphe nuclei:5HT (inhibits the locus cereuleus inhibition of raphe nuclei) causes drowsiness by interactions with RAS, thalamus, and solitary tract. Solitary tract enhances parasympathetic tone.
What is the role of Raphe nucleui during non-REM sleep?
midbrain nuclei are usually tonically supressed by RAS. Released from suppression as drowsiness begins. SErotonin inhibits brainstem structures and the thalamus.
What is the role of the reticular nucleus of the thalamus in non-REM sleep?
ascending fibers go to the cortex and increase GABA inhibitory tone (may not release GABA themselves? unclear)
What are the anatomical parts involved in REM sleep? Where are they located? Neurotransmitter? Projections?
REM-on center like nucleus reticularis pontis oralis NRPO
REM-off centers like Locus ceruleus
located in the posterior pontine tegumentum.
activation modulated by ACh and they have ACh projections to the thalamus, brainstem, and spinal cord (for atonia)
What is the 2 state theory of sleep?
2 processes:
- Process S: you build up a sleep debt throughout the day. Pay it too early (with naps), and you won’t be tired at bedtime
- Process C: circadian rhythms also influence sleep. Suprachiasmatic nucleus is the primary regulator. Circadian alertness lowest btw 3 and 7 am.
What are the phases of sleep?
Non-REM:
Phases 1 and 2 are light sleep
Phase 3 is deep slow wave sleep
REM is the stage with increased arousal threshold and the dreaming state.
N1 sleep characteristics
light sleep- response to environment
theta EEG
slow rolling eye movements and regular resps. slightly decr. muscle activity and cardiac slowing
N2 sleep characteristics
less of an environmental response than in light sleep. EEG has more slow frequency waves: delta and theta with sleep spindles. further decrease in muscle activity and eye movements; heart and breathing remain in slowed state
N3 sleep characteristics
slow wave sleep. almost no response to environment. mostly high amplitude delta. no eye movement. very deep and regular resps. continued low muscle activity/cardiac slowing.
REM sleep
increased arousal threshold. dreaming. EEG back on a more awake-like pattern: mixed freq pattern of alpha and theta waves. increased sympathetic tone. rapid saccadic eye movements. irregular resps. irregular cardiac rhythm. occasional muscle twitches but no tonic muscle tone. Increased blood flow to the penis in men. 15-25% of sleep.
