Lundy-Ekman Chapter 14: Upper Motor Neurons

Origination of the reticulospinal tract

Originates in the reticular formation in the brainstem

Role of the reticulospinal tract

• Facilitate bilateral LMNs innervating postural control and gross limb movement muscle

• Activate LMNs that elicit simultaneous contraction of muscle groups across multiple joints

• Provide anticipatory postural adjustments

• Controls basic synergies

(hip strategies for balance)

origination of the medial vestibulospinal tract

originates in the medial vestibular nucleus

Role of the Medial vestibulospinal tract

LMNs controlling neck and upper back muscles

Lateral vestibulospinal origination

Originates in the lateral vestibular nucleus

lateral vestibulospinal role

Postural muscles (facilitates ipsilateral LMN to extensors while inhibiting ipsilateral LMNs to flexors)

origination of the medial corticospinal tract

Descends from the cortex through the internal capsule and the anterior brainstem to the spinal cord

role of the medial corticospinal tract

Synapse with LMNs that control neck, shoulder, and trunk muscles

origination of the rubrospinal tract

Originates in the midbrain

role of the rubrospinal tract

Innervates contralateral neurons that power the wrist and finger extensors

origination of the lateral corticospinal tract

Originates in the cerebral cortex

role of the lateral corticospinal tract

Selective motor control of limb movements