Neurophysiology

______ Reticulospinal Tract: arises from Pontine Reticular formation. opposite effect on antigravity reflexes of SC with extension of lower limbs. Controlled by descending signals from cortex and projects ipsilaterally to SC.

_______ Tract: originates in Superior colliculus of midbrain and receives input from retina, visual cortex, and other somatosensory and auditory input. Projects to opposite side of SC at spinal level. Keeps head balanced on shoulders as body moves through space and turns head in response to stimuli.

_______ Vestibulospinal Tract: receives info about head movement and postion from vestibular apparatus. projects to cervical and thoracic levels of SC. controls neck and upper back muscles. keep head balanced on shoulders while body moves in space and keeps eyes stable as body moves so our visual image of the world remains stable. Projects bilaterally down SC.

________ Vestibulospinal Tract: receive info about gravity from vestibular apparatus. Projects ipsilaterally down SC as far as Lumbar cord; maintain upright posture and balance by activating extensor motor neurons in leg.

______ Corticospinal Tract: direct connection from cerebral cortex to spinal cord. also called pyramidal tracts. originate in primary motor cortex. synapse only in Cervical and Thoracic Cord: controls neck, shoulder, and trunk muscles.

_______ Corticospinal Tract: longest SC tract, also called pyamidal tract. originates in primary motor and premotor cortex. controls fine distal movements and fractionated movement.

Cortex--> Internal Capsule--> Cerebral Peduncle--> Pons--> Medullary Pyramid--> Pyramidal Decussation--> Lateral Column--> dorsolateral region of ventral horns and intermediate gray area: _______ Corticospinal Tract Pathway

Describe the Lateral Corticospinal Tract Pathway

______ Tract: red nucleus of midbrain. decussate in pons. join axons of corticospinal tract in lateral column of SC. upper limb flexors. most function has been replaced by corticospinal tract.

Lesion of ______ Pathway: unable to make fractionated movements of arms and hands. can't move shoulders, elbows, wrists and fingers independently. voluntary movement is slower and less accurate.

Lesion of ______ tract: paralysis on contralateral side that improve over time: Rubrospinal tract may take over.

______ reticulospinal tract: arises from lateral reticular formation; projects bilaterally from cortex and usually facilitates flexion motor neurons and inhibits extensor motor neurons, but during walking, reversed. inhibits flexor and facilitates extensor.

________ Tract: from motor areas of cortex to cranial nerve nuclei in braintstem; facilitates lower motor neuron innervating muscles of face, tongue, pharynx, larynx. Facillitates trapezius and SCM. Upper Face bilaterally controlled and Lower face contralateral.