Blood supply and neuroplasticity Flashcards
Which artery supplies the anterior system? What about the posterior system?
Anterior - internal carotid
Posterior - vertebral arteries
What does damage to the ACA cause?
Somatosensory motor deficit on contralateral body with the leg being more affected than the arm (due to somatotopic organization)
If prefrontal cortex affected then there can be changes in EF
What does damage to the MCA cause?
Somatosensory motor deficit with the arm and face being more affected than the legs
Aphasias
If damage is on the right, then left neglect
Prefrontal cortex can also be affected leading to changes in EF
What does the PCA supply?
Occipital lobe, thalamus, and inferior temporal lobe (including hippocampus)
What deeper structures does the ACA have branches going to?
Anterior striatum
Hypothalamus
Anterior limb of internal capsule
What deeper structures do branches from the MCA go to?
Caudate, putamen and GP
Posterior limb of internal capsule
What deeper structures do branches from the PCA supply?
Posterior hypothalamus, thalamus, superior midbrain
What is a hematoma?
A collection of clotting blood
What is an epidural bleed caused by?
How dangerous is it?
Tear in the middle meningeal artery
Very dangerous - fast bleeding, can die overnight
What is subdural hemorrhage caused by?
Tearing of the bridging veins (often due to impact), can be fast or slow, usually slow and not as dangerous as epidural bleeds
What causes subarachnoid hemorrhage?
How dangerous is it?
Bleed from one of the arteries of the circle of willis
Very dangerous because free bleeding
Is intracerebral hemorrhage deadly? What are the symptoms?
Can be deadly - symptoms are consistent with the area that is damaged
What is the difference between regeneration and axonal sprouting?
Regeneration - damaged axons grow and find their way back to a target
Axon sprouting - axons from undamaged parts of neurons grow new branches
What is reactive synaptogenesis?
When a synapse is formed in response to a stimulus (e.g. damaged axon)
What is the process of axon breakdown in the PNS called? What occurs?
Wallerian Degeneration
Dead axon bits are swept away by macrophages
What permits an axon to regrow to it’s target?
The neurolemma is intact (the part that surrounds the myelin) - Schwann cells provide growth factor for axon regrowth
How does the CNS deal with degradation of an axon and why is it harder for it to recover?
Astrocytes do not create a neurolemmal tube
Gliotic scar formation prevents regrowth
Instead, the surrounding areas undergo axonal sprouting to recover the function
What is use-dependent plasticity?
The cortex can reorganize itself and increase representation of parts that are used more often
Describe plasticity after deafferentiation
When a peripheral connection is severed, the area of the cortex devoted to that will start to represent the nearby areas
Describe the vicious cycle of learned non-use
If you don’t use something, the cortical representation gets smaller and it becomes harder to use it in the future
After brain injury, if you use it, you can develop cortical representation in nearby parts of the brain to continue doing the functional tasks you need to
