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PSYC233 (BB) > Sleep ( + Textbook Chapter 8 ) > Flashcards

Sleep ( + Textbook Chapter 8 ) Flashcards

1
Q

Fill-in-the-Blank:

Biological rhythms are largely ____ ____.

A

endogenous systems

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2
Q

True or False:

If the suprachiasmatic nucleus (SCN) was removed, the cells comprising it would continue to fire with an approximate 24 hour rhythm.

A

True

This brain region is known for being an internal clock or biological pacemaker used to help drive endogenous rhythms.

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3
Q

Define:

Zeitgeber

A

Environmental cues that help organisms entrain their internal rhythms to their external environment.

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4
Q

True or False:

Even under artificial conditions, some active period patterns may still occur.

A

True

These endogenously driven activity patterns may still occur, but likely with some kind of drift in the onset of activity due to biological rhythms seldom being perfectly 24 hours or one year etc.

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5
Q

List:

FIVE examples of potential circannual rhythms exhibited by humans.

A
  • Cortisol levels
  • Suicide
  • Birth weight
  • Sleep
  • OCD symptoms

Swaab, D. F., Van Someren, E. J., Zhou, J. N., & Hofman, M. A. (1996). Biological rhythms in the human life cycle and their relationship to functional changes in the suprachiasmatic nucleus. Progress in brain research, 111, 349–368. https://doi.org/10.1016/s0079-6123(08)60418-5

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6
Q

What happens to our body temperature during a 24 hour sleep-wake cycle?

A

It rises during our active period, and then drops to its lowest during the sleep period.

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7
Q

What is the role of cortisol in the circadian sleep-wake cycle?

A

Mobilising energy when we wake up.

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8
Q

True or False:

The midpoint of sleep time gets later in early adulthood, even when taking cultural factors into account.

A

True

It has also been observed in other species too.

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9
Q

True or False:

Whether you are a ‘morning’ or ‘night’ person may be largely genetically influenced.

A

True

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10
Q

Define:

Sleep

A

A state of unconsciousness, decreased activity, and primarily only responsive to internal stimuli.

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11
Q

What are the TWO main methods for measuring brain activity during sleep?

A
  • EEG (electroencephalography).
  • EOG (electrooculography).
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12
Q

What kind of waves predominate during wake periods?

A

Large amplitude α waves, with a regular pattern of typically 8 - 12 Hz.

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13
Q

List:

THREE key descriptors for stage one sleep.

A
  • Jagged activity pattern (brainwaves).
  • Low amplitude.
  • Short-lived
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14
Q

Define:

Sleep spindles

A

Bursts of neural oscillitory activity during non-rapid eye movement sleep (NREM) that usually last for at least 0.5 seconds.

These have a higher frequency than α waves, but occur regularly.

These are hypothesised to indicate the process of learning and memory consolidation during sleep.

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15
Q

Define:

K-complex

(During sleep)

A

Larger-amplitude patterns of brain activity, and may be due to short-lived external stimuli.

Like sleep spindles this is yet another Stage 2 waveform exhibited in an EEG.

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16
Q

List:

THREE key descriptors of stage two sleep.

A
  • Larger amplitude than stage one (brain waves).
  • Sleep spindles.
  • K-complexes
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17
Q

List:

TWO key changes of slow wave sleep.

A
  • Brainwave frequency decreases.
  • Physiological functions slow down.
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18
Q

List:

THREE key features of REM sleep.

A
  • Rapid eye movements.
  • Body movements.
  • Final stage of sleep.

Typically, sleeping for longer leads to more REM sleep.

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19
Q

Does the pattern of sleep stages change with age?

A

Yes

The transition through each sleep stage is not a perfect cycle, and older people may have far greater wake periods and less REM overall.

Sleep cycles become more fragmented in elderly individuals.

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20
Q

Which sleep stage predominates early in the night?

A

Slow wave.

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21
Q

Later in a sleep period, which sleep stage(s) predominate?

A

Stage two sleep & REM.

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22
Q

During which sleep stage does fine-tuning and consolidation of motor-skill learning occur?

A

Stage two sleep.

The motor cortex, pons, cerebellum, and thalamus become active during this time.

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23
Q

What TWO proteins were discovered to be crucial for neurobiological sleep rhythms?

A

Period (Per) and timeless (Tim) proteins.

This is true for many organisms, and was discovered in experiments with fruit flies.

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24
Q

What zeitgeber is particularly vital for sleep-wake cycles?

A

Light

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25
Q

What are melanopsin retinal ganglion cells?

A

A small number of ganglion cells of the retina which project to the SCN and are affected by light even if rods and cones are disrupted or dysfunctional.

These help entrain the circadian rhythm of the SCN to light as a zeitgeber.

They are mainly close to the nose area and are sensitive to blue light.

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26
Q

Do melanopsin retinal ganglion cells have a slow or a fast (de)activation?

A

They are slow to activate and deactivate.

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27
Q

Which protein(s) induce sleepiness?

A

Both period (Per) and timeless (Tim) proteins.

28
Q

When is Per and Tim mRNA concentration at its highest?

A

During the wakefulness period.

29
Q

When are Per and Tim protein concentrations at their highest?

A

Towards the end of the sleep period.

This is because it takes a while for concentrations to build up from the beginning of the sleep period.

30
Q

What effect do Per and Tim proteins have on the clock gene?

A

Inhibition

The clock gene activity stimulates mRNA synthesis, so Per and Tim act in a negative feedback loop.

31
Q

True or False:

Per and Tim concentrations are relatively independent of whether you have actually slept or not.

A

True

This may partially explain the feeling of a ‘second wind’ when you pull an all-nighter!

32
Q

True or False:

Melatonin is only produced by diurnal animals during the night.

A

False

Melatoin levels are at their highest mostly during the night for nocturnal animals too, however it has the opposite effect and instead induces wakefulness.

33
Q

What is the important role of the pituitary gland in sleep-wake cycles?

A

Melatonin production.

34
Q

For diurnal animals, what role does melatonin play in sleep-wake cycles?

A

Staying asleep.

Rather than falling asleep.

Sleep disturbances and imbalances in melatonin production are seen in many disorders, such as depression.

35
Q

What is a strong inhibitor of melatonin?

A

Caffiene

Unless highly addicted, this substance can often lead to sleep difficulties.

36
Q

Describe:

The reticular formation.

A

A network of brainstem nuclei that have extensive ascending and descending pathways to the spinal cord, and acts as a major relay and integration location.

There are a wide variety of cell and neurotransmitter types here.

37
Q

What brain region is primarily responsible for regulating arousal and consciousness?

A

The reticular formation.

38
Q

What is the role of the pontomesencephalon in wakefulness and sleep?

A

It receives information and stimulates activity of certain neurotransmitter receptors with the circadian rhythm.

For this, it receives information from the SCN too.

39
Q

Name the TWO neurotransmitters that promote wakefulness in the reticular formation.

A

Acetylcholine
&
Glutamate

40
Q

Name the neurotransmitter that promotes sleep in the reticular formation.

A

GABA

This is one of the strongest inhibitory neurotransmitters.

41
Q

Agonists of what neurotransmitter are often used for sedation or sleep disorders?

A

GABA

42
Q

Ketamine is an agonist or antagonist of what neurotransmitter?

A

A glutamate antagonist.

This induces general anaesthesia.

43
Q

Propofol is an agonist or antagonist of what neurotransmitter?

A

A GABA agonist.

This induces general anaesthesia.

44
Q

True or False:

Ketamine has antidepressant properties separate from its role in inducing general anaesthesia.

A

True

However, its other side effects make it not viable as a long-term treatment option.

45
Q

List:

THREE key descriptors of the locus coeruleus.

(In relation to sleep-wake functions)

A
  • Homogenous structure.
  • Noradrenaline/norepinephrine.
  • Increases arousal/alertness/attentive processes.
46
Q

What relationship between histamine and the hypothalamus in regards to sleep-wake processes?

A

Histaminergic neurons are localised to the tuberomammillary nucleus of the hypothalamus, and play a role in increasing alertness.

Hence, antihistamine drugs (a direct antagonist) may often induce drowsiness.

47
Q

What effect does orexin play in the hypothalamus?

A

Inreases wakefulness and alertness.

It was originally identified for its role in eating.

48
Q

What changes occur with GABA in the early stages of sleep?

A

[GABA] increases, which decreases activity in the thalamus.

This stage is where you begin to ‘shut out the noise’.

This also interferes with the spreading of signals and information throughout the brain.

49
Q

What kind of neurons are associated with GABA?

A

Small / interneurons.

50
Q

Why can some people sleep with their eyes open?

A

Thalamic activity that processes and transfers external information has decreased, and so you don’t process seeing things!

51
Q

What gives rise to sleep disturbances such as sleep walking or talking?

A

This occurs when most of the brain has inhibited activity but not all, such as motor regions.

This occurs more commonly in children.

52
Q

Define:

Lucid dreaming

A

Being aware that one is dreaming, with some being able to manipulate the dreams to varying extents.

This is actually relatively common (~23% of people regularly according to some accounts).

53
Q

Much like other sleep disturbances such as walking or talking, lucid dreaming is associated with certain brain regions still being active during sleep.

Which brain regions are associated with this?

A

The frontal and temporal cortices.

54
Q

List:

FOUR examples of negative outcomes associated with sleep disorders such as insomnia or hypersomnia.

A
  • Aggression
  • Irritability
  • Accidents
  • Psychiatric disorders (exacerbation).

MDD is associated with both of these sleep disorders depending on the individual.

55
Q

Define:

Desynchronised circadian rhythms.

A

Internally or externally driven misalignments in endogenous sleep-wake rhythms which lead to disrupted sleep patterns.

Internal factors may be misregulation of body temperature fluctuations, whilst external factors may include travelling to different time zones.

56
Q

Define:

Sleep apnea

A

Repetitive breathing disruption during sleep.

Multiple factors may cause this condition, such as genetics, hormones, or obesity (particularly in men).

57
Q

What are FIVE examples of side effects associated with sleep apnea?

A
  • Increased sleepiness
  • Learning defecits
  • Decreased rationality
  • Impulse control issues
  • Attentional issues

This is a potentially very serious condition as it increases risk of stroke, heart issues, and neuronal loss.

58
Q

Define:

Narcolepsy

A

Sudden bouts of sleepiness or sleep paralysis.

Cataplexy (sudden loss of control over muscles or sleep paralysis) occurs only in narcoleptic patients, but is not a symptom of all sufferers.

Strong emotions or stimulation tends to trigger cataplexy.

59
Q

What neurophysiological changes are associated with narcolepsy / cataplexy?

A

Reduction in orexin transmission, particularly in the lateral hypothalamus (involved in wakefulness).

Genes or environment may contribute to this condition, and is often triggered by stress.

60
Q

List:

THREE hypotheses for the purpose of sleep.

A
  • Energy conservation
  • Cellular maintenance
  • Synaptic strengthening

The final point is associated with memory consolidation and learning.

61
Q

What is the importance of the ‘energy conservation’ hypothesis of sleep in terms of an evolutionary perspective?

A

It may account for why different species have different sleep requirements.

(i.e. duration and regularity).

For example, grazers spend less time sleeping as they need to maximise time eating food for energy.

62
Q

According to the ‘energy conservation’ hypothesis of sleep, why do humans tend to sleep at night?

A

Because we a sight-based organisms who hunt and gather best during the day; sleeping at night allows us to conserve energy.

63
Q

True or False:

Humans dream only during REM sleep.

A

False

Although we do dream more during this phase.

64
Q

What is the activation pattern of certain brain regions during REM sleep?

A
  1. Pons
  2. Thalamic geniculate nucleus
  3. Occipital cortex

PGO (ponto-geniculo-occipital) waves are the propagating activity between these regions during REM.

65
Q

State:

TWO functions of REM sleep.

(Other than dreaming)

A
  • Memory formation
  • Cornea oxygenation

This especially is linked to habit formation too.

66
Q

Define:

The activation-synthesis hypothesis.

A

A hypothesis put forth to explain the occurrence of dreams as a result of cortical interpretations of random neural stimulation.

It was first proposed in 1977 by John Allan Hobson and Robert McCarley.

67
Q

Define:

The neurocognitive theory of dreaming.

A

Dreaming is the result of our brains trying to recall or imagine events, but due to inhibition of the PFC, the logic is erratic or doesn’t make sense.

PSYC233 (BB) (13 decks)

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