sleep and cortical states

Question 1

sleep definition

Answer 1

is a natural, reversible, recurrent state of reduced responsiveness to external stimulation that is accompanied by complex
and predictable changes in physiology

Question 2

sleep is characterized by

Answer 2

-Altered consciousness.
-Minimal motor & sensory activity.
-Specific pattern of brain activity.
-Reduced interactions with the external world.

Question 3

whats EEG

Answer 3

Electroencephalography(EEG) is an electrophysiological monitoring method to record electrical activity of the brain, with electrodes placed along the scalp

Question 4

EEG measures voltage currents resulting from electrical potentials (EPSP&IPESP) generated by _____ neurons, reflected in the EEG as electrical waves: ___ waves (_, __ , ___, ___ waves)

Answer 4

cortical
brain
α, β, θ, δ

Question 5

EEG is used to

Answer 5

Monitor sleep stages & diagnose sleep disorders (Polysomnography)
Diagnose neurological disorders (e.g.epilepsy, encephalopathies, stroke…)
-Monitor coma, brain death and anesthesia level

Question 6

characteristics of beta waves

Answer 6

highly alert, eyes open= low amplitude and high frequency

Question 7

characteristics of alpha waves

Answer 7

relaxed, eyes closed= low amplitude and high frequency

Question 8

characteristics of delta waves

Answer 8

deep sleep= high amplitude and low frequency

Question 9

characteristics of theta waves

Answer 9

drowsy= high amplitude and low frequency

Question 10

what are the 2 states of wakefulness

Answer 10

-active wakefulness: eyes open, active state
-resting wakefulness: eyes closed, relaxed state

Question 11

what are the 2 states of sleep

Answer 11

-non-rapid eye movement sleep (non-REM)
-rapid eye movement (REM) sleep

Question 12

EEG recording for wakefulness

Answer 12

Beta & Alpha waves: high EEG frequency (9–30 Hz) & low EEG amplitude

Question 13

EEG recording for Stage I

Answer 13

Theta waves: intermediate EEG frequency (5–8 Hz) & intermediate EEG amplitude (50 – 100 μV) and K-Complex (isolated slow wave)

Question 14

EEG recording for stage II

Answer 14

Theta waves and sleep spindle: high EEG frequency (11–15 Hz) & low EEG amplitude (50 μV).

Question 15

EEG recording for stage III &IV

Answer 15

slow waves (delta waves): low frequency (0.5 to 4 Hz) & high EEG amplitude (100 – 150 μV)

Question 16

EEG recording for REM sleep

Answer 16

Beta & Alpha waves: high EEG frequency (9–30 Hz) & low EEG amplitude (∼30 μV). The same as in Wakefulness.

Question 17

REM sleep (paradoxical sleep) frequency, amplitude, eyelids, m. tone, m. activity, predominance of what)

Answer 17

-High EEG frequency (10–30 Hz) & low EEG amplitude (∼30 μV), Beta & Alpha waves. The same as in wakefulness
-Rapid eye movements (REM): eyelids closed,
-Minimal muscle tone, muscle atonia (i.e. muscle paralysis),
-Transient muscle activity (i.e. jerky muscle activity),
-Predominance of dreams.

Question 18

sleep occurs in what kinds of cycles

Answer 18

The period of each cycle is approximately 90 minutes (1h & 1⁄2) in human (i.e. 4 – 5 cycles/night).

Question 19

what decreases in non-REM sleep throughout the night

Answer 19

Non-REM sleep is longer at the beginning of the sleep but as the sleeper becomes more rested through the night, the durations of non-REM decrease.

Question 20

when is REM sleep the shortest

Answer 20

REM sleep is short at the beginning but becomes long at the end

Question 21

During wakefulness the cerebral cortex and thalamus are kept excited by neurons of the _____ ______ System located at
the subcortical level

Answer 21

ascending arousal

Question 22

what neurons of the ascending arousal syst are in the brainstem

Answer 22

Reticular Formation (Glutamate neurons)
Brainstem nuclei (Acetylcholine neurons)
Locus Coeruleus (Noradrenaline neurons)
Dorsal Raphe (Serotonin neurons)

Question 23

what neurons of the ascending arousal syst are in the hypothalamus

Answer 23

Lateral Hypothalamus (Orexin neurons)
Posterior Hypothalamus (Histamine neurons)

Question 24

what neurons of the ascending arousal syst are in the basal forebrain

Answer 24

Acetylcholine neurons Glutamate neurons

Question 25

During wakefulness the cortex and thalamus are kept excited by

Answer 25

neurons of the Ascending Arousal System located at the subcortical level.

Question 26

Cortical neurons discharge APs with ___ & _____ patterns (i.e. not at the same time), which results in a ___ amplitude and ____ frequency EEG activity: ‘_____ EEG’ activity (i.e. beta & alpha waves).

Answer 26

fast & irregular
low
fast
desynchronized

Question 27

The arousal system neurons stimulate also motor neurons in the spinal cord to keep a ____ muscle tone during wakefulness.

Answer 27

higher

Question 28

during non-REM sleep, inhibitory neurons (mainly GABA) inhibit what to promote sleep

Answer 28

inhibit the neurons of the arousal sys

Question 29

what is dreaming

Answer 29

Dreaming is the subjective experience of imaginary images, sounds/voices, thoughts or sensations during sleep, usually involuntarily (i.e. outside the control of the dreamer).

Question 30

most of dreamings occur during what

Answer 30

REM sleep

Question 31

do animals dream and what is their subjective experience

Answer 31

Dreaming occurs in animals as well. Animals certainly undergo REM sleep, but their subjective experience is difficult to determine

Question 32

what 2 processes regulate sleep-wake cycle

Answer 32

process S (sleep homeostatic) and process C (circadian)

Question 33

what is process S

Answer 33

(Sleep Homeostatic): sleep propensity (i.e. sleep need) accumulates across the day:
-The more the person stays awake, the more the sleep propensity incerased.
-The more the person stays asleep, the more the sleep propensity decerased.

Question 34

what is process C

Answer 34

biological clock, under the control of the hypothalamus:
-Follows the light-dark cycle. affect
-Releases sleep-related hormones (e.g. Melatonin)

Question 35

sleep is important for what

Answer 35

physical, cognitive and psychological well-being

Question 36

what are the functions of sleep

Answer 36

-Resting of different parts of the body.
-Restore natural balances among the neuronal centers.
-Acceleration of neural maturation (need of sleep for youth).
-Facilitation of learning and memory (neuronal plasticity).
-Clearance of metabolic waste products generated by neural activity in the awake.
-Conservation of metabolic energy.
-Hormonal regulation.
-etc.

Question 37

what is insomnia

Answer 37

is a Non-REM Sleep deficiency characterized by a perceived inability to fall and remain asleep at night, although it may not represent a true inability to
sleep (paradoxical insomnia = sleep state misperception)

Question 38

what is hypersomnia

Answer 38

is a Wakefulness deficiency characterized by excessive daytime sleepiness. It is a failure in the activating of mechanisms that are necessary to maintain arousal during the day.

Question 39

what is narcolepsy

Answer 39

is a REM sleep dysfunction seen in the form of sudden REM sleep onset from wakefulness (sleep attacks) and excessive daytime sleepiness. It is often associated with cataplexy (muscle paralysis) following a emotional reaction (e.g. fear, laugh). Caused by the loss of orixin neurons in the hypothalamus.

Question 40

what is sleep walking (somnambulism)

Answer 40

is a Non-REM Sleep dysfunction characterized by a partial arousal (with low consciousness) from Non-REM sleep and performing activities that are usually performed during wakefulness (e.g. walking out of the room, eating, sex, driving, homicide…). A total amnesia of the event (i.e. do not recall the event).

Question 41

what is REM sleep behaviour disorder (RBD)

Answer 41

is a REM sleep dysfunction
characterized by excessive motor activity during REM sleep due to the loss of REM sleep atonia. Patients act out the contents of their dreams. RBD is often a precursor to neurodegenerative diseases (e.g., Parkinson’s, Lewy body dementia…)

Question 42

what is REM sleep behaviour disorder (RBD)

Answer 42

is a REM sleep dysfunction
characterized by excessive motor activity during REM sleep due to the loss of REM sleep atonia. Patients act out the contents of their dreams. RBD is often a precursor to neurodegenerative diseases (e.g., Parkinson’s, Lewy body dementia…)