CNS Lecture 5 Flashcards

1
Q

The Cerebellum receives sensory input from the _______ and motor commands from the _____

A

The Cerebellum receives sensory input from the spinal cord and motor commands from the cerebral cortex

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2
Q

What are the four functional divisions of the Cerebellum?

A
  1. Vermis: posture, meck and axial (trunk) musculature)
  2. Intermediate zone: lovomotion
  3. Lateral zone: coordinating complex, skilled movements of arms, hands and fingers
  4. Flocculonodular lobe: balance
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3
Q

For each of the four functional divisions of the cerebellum, describe what they are concerned with:

  1. Vermis: _________
  2. Intermediate zone: _______
  3. Lateral zone: _________
  4. Flocculonodular lobe: _______
A

For each of the four functional divisions of the cerebellum, describe what they are concerned with:

Vermis: posture, neck and axial (trunk) musculature)

Intermediate zone: locomotion

Lateral zone: coordinating complex, skilled movements of arms, hands and fingers

Flocculonodular lobe: balance

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4
Q

There is a large nuclei deep within the cerebellum called the:

A

Basal Ganglia

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5
Q

The basal ganglia form which system?

A

Extrapyramidal system

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6
Q

What are the basal ganglia involved in?

A

Initiating movement and suppressing activity of muscles that would resist the intended movement (antagonist muscles)

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7
Q

What disorders can arise from lesions in basal ganglia?

A
  • Parkinson’s disease
    • Poverty of movement (bradykinesia - slow movement)
    • Rigidity
    • Tremor
  • Dyskinesia - Too much movement:
    • Huntington’s chorea
    • Tourette’s
    • hemiballismus
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8
Q

What are four functions that the brainstem is involved in?

A
  1. Control of respiratory and cardiovascular musculature
  2. Control transmission in sensory, motor, reflex and pain pathways
  3. initiation of movement
  4. Supplying NT’s to different parts of the brain
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9
Q

What particular area of the brainstem is involved in the initiation of locomotion?

A

Midbrain locomotor area (MLA)

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10
Q

What does the EEG (electroencephalogram) monitor?

A

Electrical activity in the brain

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11
Q

What are the three stages of NREM sleep?

A

NREM (slow-wave) sleep:

  1. Stage N1
  2. Stage N2
  3. Stage N3
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12
Q

During this sleep stage:

  • Light sleep
  • Relatively easy to wake subject
A

Stage N1

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13
Q

What is Stage N2?

What would you see on the EEG?

A
  • Second stage of NREM (slow-wave) sleep.
  • Deeper sleep than N1 (ie harder to wake someone up)
  • EEG:
    • Alpha waves replaced by random waves of greater amplitude
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14
Q

What would you see on an EEG for the N1 stage?

A

Alpha waves reduced in frequency, amplitude and percentage of time present

Gaps in alpha rhythm filled with theta and delta activity

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15
Q

What is the N3 stage?

What would you see on the EEG?

A
  • Third stage of NREM (slow wave sleep)
  • Deep sleep - more difficult to wake
  • EEG:
    • Much theta and delta activity
    • progressive increase in delta
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16
Q

What is REM sleep?

What does the EEG look like?

A
  • aka paradoxical sleep
  • stage associated with dreaming, rapid eye movement, relaxed muscles, active brain
  • EEG:
    • waves look like alert wakefulness - beta rhythm
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17
Q

What are the voltage fluctuations recorded by an EEG made up of?

A

Summed, synchronous, post-synaptic potentials of many neurons

Waveforms vary with behavioural states: attention, arousal, sleep, dreaming

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18
Q

In ______ _______ voltage fluctuations can become very large

A

In epileptic siezures voltage fluctuations can become very large

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19
Q

In the vicinity of brain tumours where neurons have died, what does the EEG look like?

A

EEG is small or absent

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20
Q

Before organs are removed what is used to verify brain death?

A

EEG

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21
Q
A
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22
Q

What are sleep spindles?

A

A burst of oscillatory brain activity visible on an EEG that occurs during stage 2 sleep

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23
Q

What is the Glasgow coma scale?

A

Important clinical scale to classify the level of consciousness of a person

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24
Q

What is the glasgow coma scale based on?

A
  • eye movements
  • responses to questions
  • whether the person makes voluntary movements and can obey commands to move their limbs
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25
Q

What are three criteria for brain death?

A
  1. nature and duration of the coma must be known
  2. cerebral and brainstem function are absent
  3. supplementary criteria includes a flat EEG for 30 minutes
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26
Q

What is the Reticular Activating System?

A

set of nuclei in the brainstem and hypothalamus that controls sleep, wakefulness and arousal

27
Q

What activates neurons in the RAS (reticular activating system) during wakefulness?

A

Visual and other sensory inputs

28
Q

The activated neurons of the Brainstem RAS release _______ to the ______ and ______

A

The activated neurons of the Brainstem RAS release monoamines (norepinephrine, serotonin and histamine) to the hypothalamus and other brain areas

29
Q

The hypothalamus supplies _______ to the _______ to maintain wakefulness

A

The hypothalamus supplies orexins to the thalamus to maintain wakefulness

30
Q

What are orexins?

A

Neuropeptide hormone

(supplied by hypothalamus to thalamus to maintain wakefulness)

31
Q

What activates orexin-producing neurons in the morning and secretes melatonin at dusk?

(sets circadian rhythm)

A

Suprachiasmatic nucleus activates orexin-producing neurons in the morning and secretes melatonin at dusk

32
Q

What is the “sleep centre”?

A

Pre-optic nucleus in hypothalamus that delivers GABA-ergic inhibition of RAS - reducing orexin levels

33
Q

What is the RAS inhibited by?

A

GABA agonist sedatives (eg valium, xanax, anti-histamines etc)

34
Q

Small lesions in the RAS can produce:

A

A coma lasting for months or years

35
Q

How is wakefulness maintained?

  1. Orexin-producing neurons are activated by:
    • the ________ of the hypothalamus
    • a ______ balance (eg low blood glucose causing hunger)
    • Activity of the _______ system
  2. _______- concerned with memory and motion triggers the drive to explore and move
  3. Orexin neurons then release ______ which have what effect on the sleep centre?
A
  1. Orexin-producing neurons are activated by:
    • the suprachiasmatic nucleus of the hypothalamus
    • a negative energy balance (eg low blood glucose causing hunger)
    • Activity of the limbic system
  2. Limbic system- concerned with memory and motion triggers the drive to explore and move
  3. Orexin neurons then release monoamines (serotonin and noradrenaline) which inhibit the sleep centre and, via the thalamus, activate large parts of the cerebral cortex
36
Q

How is the transition from wake to sleep carried out?

  1. Sleep centre is activated by a gradual increase in the blood concentration of ________
  2. Increase in ^ inhibits activation of the _______ in the suprachiasmatic nucleus
  3. Result in inhibition of activation in the _________ neurons in the RAS which results in a reduced drive to the thalamus and cerebral cortex
A

How is the transition from wake to sleep carried out?

  1. Sleep centre is activated by a gradual increase in the blood concentration of adenosine
  2. Increase in ^ inhibits activation of the orexin-producing neurons in the suprachiasmatic nucleus
  3. Result in inhibition of activation in the monoaminergic neurons in the RAS which results in a reduced drive to the thalamus and cerebral cortex
37
Q

What are the 3 characteristics of consciousness?

A
  1. Awareness of the passage of time
  2. Awareness of external sensory inputs
  3. Awareness of internal states such as fatigue, thirst, happiness memories, reasoning, ideas
38
Q

What are two main aspects of Conscious experiences?

A
  1. Selective attention
  2. Conscious perception
39
Q

What is selective attention?

A
  • Attention shifts from one focus or attractor to another
40
Q

What are coincident attractors?

A

Visual and auditory inputs coming from the same direction

-more likely to trigger a shift in attention than separate attractors

41
Q

What is conscious perception?

A
  • Specific sets of neurons in different parts of the brain temporarily function together to generate the consciousness experience
  • A central brain area selects and illuminates a temporary set of neurons in different separated brain areas (spotlight affect)
42
Q

What is hemi-neglect and how might it occur?

A
  • After a stroke affecting parietal lobe
    • person is unaware of half of their visual field
  • Destruction of specific brain areas that abolishes selective parts of consciously perceived inputs
43
Q

What are the two divisions of motivation?

A

Primary and Secondary motivated behaviours

44
Q

What are primary motivated behaviours?

A

Relate to homeostasis

  • eg maintaining water balance, nutrition, body temperature
45
Q

What are secondary motivated behaviours?

A

Behaviours resulting in pleasure

  • can be disadvantageous (eg over-eating, taking recreational drugs)
46
Q

What is the concept of “reward” and how does it explain motivation?

“mesolimbic dopamine pathway”

A

The idea is that there is a pathway in the brainstem nuclei that releases dopamine within the frontal lobe of the brain which elicits pleasure (reward)

47
Q

What are emotions

A

Internal attitudes toward events and the environment

-external responded (emotional behaviour)

48
Q

What can elicit rage responses?

A

Electrical stimulation in lateral hypothalamus elicits rage responses

49
Q

Lesions in which region results in absence of fear?

A

Amygdala

50
Q

How do antidepressants manage depression?

A
  • act by maintaining levels of serotonin and norepinephrine at synapses in the CNS
  • Thought that act via neurogenesis (generation of new neurons)
51
Q

How is substance dependence diagnosed?

A

When 3+ of the 7 specified criteria occur within a twelve-month period

52
Q

What are the two divisions of Memory?

A
  1. Working Memory (Short-term memory)
    • episodic
    • visuospatial
    • phonological
  2. Long-term Memory
    • Declarative
    • Procedural
53
Q

What is Working memory and what does Working memory (short term memory) include?

A
  • Easily acquired, quickly lost
    • Episodic
      • recent events/ places
    • Visuospatial
      • recent sights, locations
    • Phonological
      • recent words, sounds
54
Q

What is Long term memory and what are it’s divisions?

A
  • Slower period of acquisition, last for much longer, even a lifetime
  1. Declarative (involves consciousness)
    1. Semantic
      • facts
    2. Episodic
      • personal experience
  2. Procedural (mainly subconscious)
    1. Stimulus-response behaviours
    2. motor skills
55
Q

What is memory consolidation and where does it (most-likely) occur?

A
  • Transfer from short-term to long-term memory
  • occurs in the temporal lobe
  • probably involves reward systems involving the hypothalamus
56
Q

The _______ is implicated in consolidating stimulus-response associations taught during operant conditioning and in solving sequence tasks

A

The caudate nucleus is implicated in consolidating stimulus-response associations taught during operant conditioning and in solving sequence tasks

57
Q

What is amnesia?

A

absence of memory

  • retrograde
  • anterograde
58
Q

Loss of memory in events prior to the injury is considered:

A

Retrograde amnesia

59
Q

Loss of memory of events after the injury is called:

A

Anterograde amnesia

60
Q

What is a concussion measured by?

A

Type and duration of amnesia

61
Q

What is korsakoff’s syndrome?

A

Complete anterograde amnesia

-often occurs in chronic alcoholism

62
Q

What causes Korsakoff’s Syndrome?

A

Damage to hippocampus

  • complete anterograde amnesia
  • can be caused by chronic alcoholism
63
Q

What is Alzheimers caused by?

A

Degeneration of memory-holding neurons

  • perhaps due to proteins called amyloid precursor proteins that cause excitotoxicity
    • Neurons are damaged by over-excitation