Restorative therapies for sensorimotor function after stroke (NEEDS IMPROVEMENT) Flashcards
Describe the anatomy of the human corticospinal tract
White matter motor pathway.
The right hemisphere supplies the left spinal cord.
The lateral corticospinal tract runs from the cerebral cortex through the midbrain, pons and medulla where it descussates contralaterally (crosses sides) into the spinal tract.
The motor cortex of the right brain controls the left side of the body and vice versa.
The rubrospinal tract operates similarly, except it originates in the red nucleus in the midbrain.
Why can restored motor function be induced in unilateral cerebral ischemia?
Stroke kills neurons on one side, whose descending neurones degenerate, losing input to ipsilateral red nucleus and contralateral spinal cord. However a spared cortex remains. Neurons sprouting to the contralateral side could restore function.
What is the function and target of nogo-A antibodies?
They target a growth inhibitory molecule called NOGO-A. This molecule is found on the cell surface of neurons, and prevents axonal growth of any neurons whose receptors make contact with NOGO-A. The antibodies prevent this receptor binding, and therefore promote neuronal growth.
NOGO-A is therefore used to promote motor recovering after stroke by promoting neuronal growth within corticospinal neurons.
What is an important consideration for NOGO-A therapy?
NOGO-A therapy should not be administered at the same time as rehabilitation training. This causes extensive branching, aberrant synapsing to the non-motor laminae of the dorsal horn and overshooting. No motor improvement is seen.
It must be given prior to any training, to allow synapses to form appropriately.
What are some limitations to using animal models for therapies such as NOGO-A?
Animal models do not have identical motor systems i.e. they may differ in the anatomical organisation of spinal tracts.
