Lecture 9 Flashcards
(32 cards)
What are the two types of strokes?
- Ischemic Stroke
- Hemorrhagic Stroke
Define:
Ischemic Stroke
- Blockage to artery of a vein
Define:
Hemorrhagic Stroke
- Uncontrolled blood pressure that leads to tearing of artery wall causing blood leakage
For ischemic strokes, list:
- Contributing factors
- Results
- 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
Why are ischemic strokes a good model to study anatomy link to function?
Ischemic strokes result in very focal damage to the brain
For hemorrhagic strokes, list:
- Contributing factors
- Results
- Uncontrolled blood pressure
- Results in neural and glial cell death
- Typically results in a larger area of lesion
How do strokes appear on MRI? Why?
Generally show as dark areas on MRI
* Due to tissue loss and filling with cerebrospinal fluid
What type of MRI images are there?
- T1 weighted image
- T2 weighted image
Define and describe:
T1 weighted MRI images
- 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
Define and describe:
T2 weighted MRI image
- 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
True or False:
Brain surgery is done with the patient unconscious
False, brain surgery is done while the person is conscious
Why is brain surgery done while the person is conscious?
- 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
How do surgeons determine what areas of the brain to avoid during brain surgery?
By using weak electric signals to probe the brain, determining what each part of the brain does
True or False:
It is important to map out the brain before any surgery
True
Describe:
Phantom limb pain
Patients of amputation still feel the limb or the pain in the limb when the patient thinks of it
Where is the map of the body located in the brain?
Somatosensory cortex
Why does phantom limb pain occur?
- 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
What does phantom limb pain imply?
Neuroplasticity
How is phantom limb pain treated?
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
State:
Location of SMA
Located just ahead (anterior) of M1, directly adjacent
Describe:
Supplementary Motor Area (SMA)
- Direct projections (~10%)
- Very little direct control to alpha motor neurons
- Majority has cortico-cortico connections, projecting from SMA to M1
Describe the function of:
Supplementary Motor Area (SMA)
- Inolved in sequencing movements, sequence specificity
- Lesions cause challenges to movement seuqnecing, activating musles at inappropriate times when performing a movement
True or False:
The more challenging an activity becomes, the more activity that SMA does
True
True or False:
The SMA is active for external stimulus triggered movements
False, the SMA is active for internally generated movements (when you decide to move)
