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43 Cards in this Set
- Front
- Back
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How is sleep monitored during sleep studies?
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EEG- cortical activity
EMG- skeletal muscle activity EOG- eye movement ECG- HR *breathing, oxygen levels, position |
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EEG detects & records the activity of cortical neurons. What does this activity consist of?
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continuous oscillating waveforms that arise from dendrites of pyramidal neurons in the cerebral cortex
(reflects summations of EPSPs & IPSPs from many dendrites) |
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What modulates cortical activity?
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-synaptic input from other cortical areas, basal forebrain, thalamus, & brainstem
-cholinergic & monoaminergic input from forebrain & brainstem |
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Fast, low-amplitude activity
associated w/ waking state, eyes open Usually recorded in anterior head region 14-30 Hz |
Beta activity
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Rhythmic, moderate frequency
associated w/ relaxed state, eyes closed Usually recorded in posterior head region 8-13 Hz |
Alpha activity
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Rhythmic, slow frequency
associated w/ drowsy state in adults, normal in children 4-7 Hz |
Theta activity
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Very low frequency
associated w/ sleeping adult, normal in infant 0-4 Hz |
Delta activity
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Connect the following stages w/ the dominant wave activity:
Awake Drowsy Stage 1 Stage 2 Slow-wave sleep (stages 3 & 4) REM sleep |
Awake- beta
Drowsy- alpha NREM Stage 1- theta NREM Stage 2- theta + sleep spindles + K complex NREM Stage 3- theta + irregular delta NREM Stage 4- primarily delta REM sleep- delta |
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Two main components of Consciousness
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1. Wakefulness/arousal
2. Awareness/experience |
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Mechanisms that maintain wakefulness/arousal
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- tonic activity cholinergic & monoaminergic neurons maintains excitability of thalamocortical circuits
- sensory pathways send collaterals to excite brainstem reticular activating system |
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Role of the thalamus & cortex in thalamocortical circuit maintenance of wakefulness/arousal
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thalamus:
-inhibits rhythmic burst activity -promotes tonic firing -transfers info to cortex cortex: -increases responsiveness of cortical neurons |
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Cholinergic contribution to arousal system via
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tegmentum:
pedunculopontine tegmental nucleus lateraldorsal tegmental nucleus basal forebrain: basal nucleus of Meynert |
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Monoaminergic contribution to arousal system via
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Hypothalamus:
locus ceruleus (NE) rostral raphe nuclei (5-HT) tuberomamillary nucleus (histamine) |
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Attention is a process of enhancing response to specific stimuli while filtering out rest. What parts of the cortex are important for this?
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prefrontal cortex
parietal association cortex |
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__________neurons in the basal nucleus of Meynert – receive input from prefrontal cortex and send projections to ______________& _____________ facilitating selection and processing of behaviorally significant stimuli.
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Cholinergic neurons
primary and association sensory areas |
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____________neurons in the locus ceruleus - send projections to _________________& ___________________ to mediate stress-induced increase in attention.
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Noradrenergic neurons
basal forebrain and sensory cortex |
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____________ reward system – stemming from the VTA– sends projections to_________________________________ in response to reward & important for motivated behavior.
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Dopaminergic reward system
(limbic and) prefrontal cortex |
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Which two groups will also modulate activity of thalamic relay nuclei?
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cholinergic (Meynert) & noradrenergic (locus ceruleus)
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General decrease in brain activity
stable vital functions eye movements absent some postural muscle tone present cerebral blood flow & oxygen consumption decrease some restorative effects small decrease in core body temp REM or NREM? |
NREM
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High frequency, low amplitude brain activity
fluctuations in BP, HR, breathing rapid eye movements profound loss of skeletal muscle tone w/ twitches Erection may occur thermoregulation is reduced/lost (poikilothermia) REM or NREM? |
REM
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Which sleep type is associated w/ dreams & nightmares?
What are the physiological correlates of images perceived during dreaming? |
REM
PGO (pontogeniculate-occipital) spikes |
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PGO spikes are eye movements associated w/ bursting activity in the ___________, ____________, & ____________.
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pontine tegementum,
lateral geniculate nuclei, & occipital lobe |
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Describe the sleep cycle
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1. sleep onset
2. stepwise descent from stage 1-4 3. rapid shift to REM (REM lasts from 10-30 min progressively) 4. abrupt return to stage 2 5. descent from stage 2-4 (stage 4 progressively decreases) 6. Rapid return to REM & cycle through steps 3-6 7. wake |
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How long does the cyclic pattern of sleep from stage 2-4 to REM and back to 2 last?
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70- 90 mins each
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After sleep onset, how long does the descent from NREM stage 1 to stage 4 take?
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about 60 mins
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The ___________ nucleus is the circadian pacemaker of the hypothalamus.
What does it do? |
suprachiasmatic nucleus (SCN)
Regulates sleep wake cycles, which last about 24 hrs entirely |
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The suprachiasmatic nucleus (SCN) is entrained to day-night cycle by what?
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retinal projections
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The SCN controls the release of what?
how? |
melatonin (from pineal gland)
by inhibition of paraventricular nucleus in absence of daylight (released inhibition= melatonin release= daylight) |
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The SCN also controls sleep wake cycle via polysynaptic connections to the ____________________
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ventrolateral preoptic area
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During the waking state, the activity of histamine neurons of the _______________________ maintains wakefullness
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tuberomammilary nucleus
(thus why antihistamine meds cause drowsiness) |
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____________ releasing neurons of the posterolateral hypothalamus project to and activate the cholinergic and monoaminergic neurons of the arousal system.
What does this prevent? |
Orexin (hypocretin) releasing neurons
prevents abrupt transition from wake to sleep |
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During NREM sleep, the SCN signals the_________area of the hypothalamus, a major sleep promoting region.
What does this area project as a result? |
ventrolateral preoptic area
GABAergic projections ^ which inhibit the monoaminergic & cholinergic group of the arousal sytem during sleep |
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During prolonged wakefulness, what inhibits the activity of resident cholinergic projections to promote sleep?
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adenosine (a putative somnogen)
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What marks the onset of REM sleep?
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* an increase in cholinergic neuron (REM-on cell) activity in the pons
& maximal suppression of brainstem monaminergic neurons |
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Where do REM-on cells project?
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*PPRF, generate rapid eye movements
*medullary reticular formation, glycineric projections to lateral reticulospinal tract for muscle atonia |
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What main difference in cortical circuit activity are seen in the switch to REM sleep?
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-thalamic relay neurons switch to tonic, single spike mode
-cortical activation reflects low amplitude, fast EEG (similar to wake state) -cortical activity (memory & emotion) is online but now driven by INTERNAL stimuli (stored info) |
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Wakefullness, NREM, or REM?
cholingergic nuclei of pons-midbrain jxn- Ach- Active Locus coerulus- Norepi- Active Raphe nuclei- 5-HT- Active Tuberomammillary nuclei- Histamine- Active Lateral Hypothalamus- Orexin- Active |
Wakefullness
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Wakefullness, NREM, or REM?
cholingergic nuclei of pons-midbrain jxn- Ach- Decrease Locus coerulus- Norepi- Decrease Raphe nuclei- 5-HT- Decrease |
NREM
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Wakefullness, NREM, or REM?
cholingergic nuclei of pons-midbrain jxn- Ach- Active Locus coerulus- Norepi- Inactive Raphe nuclei- 5-HT- Inactive |
REM
(*cholinergic nuclei active (PGO waves)) |
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What sleep disorder?
REM intrudes into wakefullness Disruption of orexin (hypocretin) neurotransmission Loss of neurons in posterolateral hypothalamus Associated with: cataplexy (atonia induced by emotions) sleep paralysis (skeletal muscle) hypagogic halluciations (during sleep onset) disturbed nocturnal sleep |
Narcolepsy
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What sleep disorder
Violent/inappropriate motor activity during REM Loss of motor atonia during REM (talking, jumping, etc) Associated with: Neurodegenerative disorders SSRI antidepressent medications |
REM Sleep Behavior disorder
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What sleep disorder?
Abnormal or incomplete arousal from late stage NREM Sleep walking (somnambulism) Sleep terrors (abrupt arousal followed by agitation) Associated with: CNS depressant use (alcohol) internal stimuli emotional stress |
NREM arousal disorder (parasomnia)
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What sleep disorder?
Periodic/repetitive flexion-extension limb movements Occurs during NREM stage 1 & 2 Causes intermittent arousal/awakening Associated with: Restless Leg Syndrome Dopaminergic agonist used |
Periodic limb movement disorder
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