Neuroscience Tutorial 2 Flashcards
What is Brown-Sequard syndrome?
- Damage to one side of the spinal cord
- Results in loss of pain and temperature sensation in the leg on the contralateral side, loss of touch sensation and movement in the isilateral leg
- This is because the spinothalamic tract decussates in the spinal cord, dorsal column decussates in the midbrain, and the lateral corticospinal tract decussates in the midbrain
What would the symptoms be following a stroke to the right parietal lobe?
- Left hand and forearm weakness and loss of sensation
- Due to damage to the primary motor cortex following occlusion of the middle meningeal artery
What can happen following a stroke?
- Stroke induced epilepsy causing jerking movements of the arm, due to random action potential generation from the primary motor cortex
- Spreading of loss of function to other sites of the brain
- Epilepsy can be treated with anti-convulsant drugs
Which pathways are affected in locked in syndrome?
Corticospinal and corticobulbar tracts
If a patient can move eyes vertically but not horizontally, where is the lesion causing this?
- Basal part of the upper pons
- We know this because the oculomotor nerve is functional, and the abducens nerve is not functional.
- Therefore, the lesion must be above the nucleus of the abducens but below the oculomotor nerve
Why are sensation and consciousness not effected in locked in syndrome?
As the lesion is in the anterior part of the brainstem, so the ascending sensory tracts and reticular formation are intact.
Obstruction of which artery results in locked in syndrome?
- Basillar artery (which runs up the brainstem)
- The rest of the brain has correct blood supply as there are many inputs to the circle of willis
Why might coldness and pressure be felt in the arm following a stroke affecting the primary motor cortex?
Damage spreads to the somatosensory cortex, which causes feelings of extreme cold and pressure despite a lack of detection by the sensory nerve
