Motor System 2 Flashcards
Differentiate between upper and lower motor neuron
Upper motor neurons are in CNS, which communicate with lower motor neurons. Lower Motor neurons communicate with muscles
What is the precentral gyros ?
The primary motor cortex- recruits the upper motor neurons required
What is the function of basal ganglia and cerebellum ?
Basal ganglia and cerebellum refine motor activity
What is the function of corticospinal tract?
Initiation and control of voluntary motor activity
Motor planning areas which include prefrontal Corticles and limbic association areas project to —> premotor areas—> which in turn project to primary motor cortex
This shows emotions effect motor activity
What is Brodmann’s area for the primary motor cortex?
Area 4
What is the route of the corticospinal tract?
Corona radiata; internal capsule (posterior limb); crus cerebri; basilar pons; lateral corticospinal tract in spinal cord; synapses on alpha and gamma in ventral horn
What is the role of the corticospinal tract?
Voluntary movement (contraction of flexor muscles)
- modified from the basal ganglia and the cerebellum via the thalamus
- this tract also plays a key role in coordinating contractions of muscle groups activated during “reaching and walking”
Give an example of the corticospinal tract
Corticospinal tract
Describe upper motor neurons
They arise from the primary motor cortex. They project through the corina radiata, internal corpuscle, crus cerebri, basal pons and pyramid
Why is the brain side that controls movement opposite from the output of motor activity?
The corticospinal tract switches around and sends message to limbs on the opppoeite side of the brain then received
What are the symptoms of upper motor neuron lesion ?
Upper motor lesion:
-lesion above decussation:
Symptoms contra-lateral to the lesion(on the opposite side to the lesion)
-lesion below the decussation:
Symptoms ipsi-lateral to the lesion (same side)
- Hyperflexia
- Extensor plantar response (toes, big toe, run an object on the sole of the feet)
- first flaccid paralysis, later spastic paralysis
What are the symptoms of lower motor lesion?
Lower motor neuron lesion:
-Lesion of the cell bodies of the alpha motor neuron
Symptoms IPsi-lateral to the lesion
Hyporreflexia
Flaccid paralysis
What are the corticobulbar tract?
Neurons Start in the cortex and end in the brain stem
They’re responsible for motor function in head and neck
These fibers also decussation and synapse with lower motor neurons (the cranial nerves)
What causes central Paralysis of genioglossus muscle
Responsible for tongue protrusion, innervated by hypoglossal (cranial nerve 12)
If there is corticolesion(upper motor neuron lesion) in the cerebral cortex, there is no communication with the left hypoglossal nerve, then the right hypoglossal nerves still active
This causes the tongue to deviate to the left side upon protrusion (right hypoglossal nerve innervates the right genioglossus, which takes the tongue to the left side)
What causes peripheral paralysis of genioglossus muscle?
When there is a lesion in one of the peripheral (In this case, hypoglossal) there will be a deviation in the same side of the lesion. If there is a lesion in the left hypoglossal nerve, then the right hypoglossal nerve will activate the right genioglossus muscle which takes the tongue to the left
