Lateral Corticospinal Tract

Rubrospinal Tract

Medullary Reticulospinal Tract

Pontine Reticulospinal Tract

Lateral Vestibulospinal Tract

Medial Vestibulospinal Tract

Flexors - dorsolateral

Extensors - ventromedial

Proximal muscles - medial 

Distal muscles - lateral

Corticospinal Tract

Rubrospinal Tract

Reticulospinal Tract

Vestibulospinal tract

Primary Motor 30% - targets neurons of spinal cord that control individual muscles;

Somatosensory 40% - targets dorsal column nuclei of medulla and dorsal horn of spinal cord or nucleus gracilis or cuneatus ; filters out irrelevant info

Premotor 30% - controls whole body movements; acts to synchronize movements

Posterior limb - Corticospinal Tract

Genu - Corticobulbar Tract

Anterior Limb - Fronto-pontine and fronto-thalamic tracts (cerebellum)

• originates at red nucleus
• crosses over and travels with corticospinal tract
• goes to cervical levels and innervates flexor motor neurons

• originates at lateral vestibular nuclei
• innervates ipsilateral extensor  neurons at cervical and lumbar levels

• aka descending MLF
• originates from medial vestibular nucleus
• descends to cervical levels and coordinates head/neck movements with ascending MLF

• originates at Retic formation at Pons 
• facilitates extensor motor neurons
• targets alpha and gamma motor neurons
• controls muscle tone

Lateral Reticulospinal tract

lesion at cortex, int. capsule, crus cerebri, lower medulla, or lateral funiculus

effects of spinal cord: babinski, spasticity, paralysis, hyperreflexia

effects on brainstem: loss of control over cranial nerve functions, pseudobulbar palsy

Lesions ons:

premotor cortex, postcentral gyrus, precentral gyrus, posterior parietal lobe

premotor cortex: apraxia (can't makes sequenced movements)

postcentral gyrus: ataxia (clumsy)

precentral gyrus: UMN paralysis

right posterior parietal lobe: sensory denial on left side