Lecture 9 Flashcards

1
Q

What are the two types of strokes?

A
  1. Ischemic Stroke
  2. Hemorrhagic Stroke
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2
Q

Define:

Ischemic Stroke

A
  • Blockage to artery of a vein
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3
Q

Define:

Hemorrhagic Stroke

A
  • Uncontrolled blood pressure that leads to tearing of artery wall causing blood leakage
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4
Q

For ischemic strokes, list:

  • Contributing factors
  • Results
A
  • Atherosclerosis, uncontrolled cholesterol are all factors
  • Prevents blood flow to brain
  • Glial cells and neurons cannot exist without continuous supply in oxygen, thus causes neural and glial cell death
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5
Q

Why are ischemic strokes a good model to study anatomy link to function?

A

Ischemic strokes result in very focal damage to the brain

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6
Q

For hemorrhagic strokes, list:

  • Contributing factors
  • Results
A
  • Uncontrolled blood pressure
  • Results in neural and glial cell death
  • Typically results in a larger area of lesion
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7
Q

How do strokes appear on MRI? Why?

A

Generally show as dark areas on MRI
* Due to tissue loss and filling with cerebrospinal fluid

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8
Q

What type of MRI images are there?

A
  1. T1 weighted image
  2. T2 weighted image
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9
Q

Define and describe:

T1 weighted MRI images

A
  • Fat (myelin, on the sheath of axon) appears bright
  • White tracks are the axons connecting all of the nervous system
  • May be used in someone with MS, to see degeneration of the myelin sheath is occurring
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10
Q

Define and describe:

T2 weighted MRI image

A
  • Water (cerebrospinal fluid) appears bright
  • May be used in someone with a stroke, to see the margins and area of the lesion occurring in the brain
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11
Q

True or False:

Brain surgery is done with the patient unconscious

A

False, brain surgery is done while the person is conscious

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12
Q

Why is brain surgery done while the person is conscious?

A
  • The person doesn’t feel pain as the brain doesn’t have pain receptors (they only feel pressure)
  • Allows surgeons to keep watch at what each area of the brain does
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13
Q

How do surgeons determine what areas of the brain to avoid during brain surgery?

A

By using weak electric signals to probe the brain, determining what each part of the brain does

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14
Q

True or False:

It is important to map out the brain before any surgery

A

True

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15
Q

Describe:

Phantom limb pain

A

Patients of amputation still feel the limb or the pain in the limb when the patient thinks of it

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16
Q

Where is the map of the body located in the brain?

A

Somatosensory cortex

17
Q

Why does phantom limb pain occur?

A
  • The SMA territories for the face and hand are beside each other
  • When the limb is amputated, the face area invades the area for the arm
  • Result: When q-tip is ran along the cheek, the individual felt it in their arm
18
Q

What does phantom limb pain imply?

A

Neuroplasticity

19
Q

How is phantom limb pain treated?

A

By using mirror box
* Theory: Since the arm is amputated, the brain to arm signals become a positive feedback loop causing pain from overclenching
* Tricks the brain into thinking the hand still exists

20
Q

State:

Location of SMA

A

Located just ahead (anterior) of M1, directly adjacent

21
Q

Describe:

Supplementary Motor Area (SMA)

A
  • Direct projections (~10%)
  • Very little direct control to alpha motor neurons
  • Majority has cortico-cortico connections, projecting from SMA to M1
22
Q

Describe the function of:

Supplementary Motor Area (SMA)

A
  • Inolved in sequencing movements, sequence specificity
  • Lesions cause challenges to movement seuqnecing, activating musles at inappropriate times when performing a movement
23
Q

True or False:

The more challenging an activity becomes, the more activity that SMA does

A

True

24
Q

True or False:

The SMA is active for external stimulus triggered movements

A

False, the SMA is active for internally generated movements (when you decide to move)

25
Q

True or False:

SMA activity increases with movement complexity

A

True

26
Q

True or False:

The SMA is active for real and “imagined” movements

A

True

27
Q

Is the SMA an area that is involved in mtoro imaging?

A

It is robustly involved in motor imaging

28
Q

Describe:

Premotor Cortex (PMA)

A
  • Fewer direct projections (5%) to spinal cord, majority is cortico-cortico and cortico-subcortico
  • Strong connections with subcortical structures (cerebellum)
29
Q

What triggers the premotor cortex?

A

Triggered by external sensory events and delayed action (e.x. car causing you to jump out of the way)

30
Q

What is the PMA important for?

A
  • Obstacle avoidance
  • Perseveration behaviours
31
Q

Define:

Perseveration behaviours

A

Repetitive actions despite it leading to no result

32
Q

What will PMA lesions cause?

A

Difficulty in obstacle avoidance, bumping into everything in their way