Neuroscience Week 3: Descending Spinal Cord Pathways Flashcards
Lateral corticospinal tract origination
Motor Cortices (mostly)
Lateral corticospinal tract Terminate
Contralaterally in spinal motor neurons
Lateral corticospinal tract Function
innervate distal muscularture for fine motor movements
Medial aspect of lateral corticospinal tract

Arm fibers

Lateral aspect of lateral corticospinal tract

Leg fibers

Anterior corticospinal Tract Origin
Motor cortices (mostly)
Anterior corticospinal Tract Termination
Contralaterally in the spinal motor neurons
Anterior corticospinal Tract Function
inverate proximal muscles for gross motor movements
Hypothalamospinal tract Origin
Hypothalamus
Hypothalamospinal tract Termination
ipsilaterally
Hypothalamospinal tract Function
Hypothalamic control of autonomic function
Somatotopy: Anterior portion of the ventral horn

Extensors

Somatotopy: Posterior portion of the ventral horn

Flexors

Somatotopy: Medial portion of the ventral horn

Proximal muscles

Somatotopy: Lateral portion of the ventral horn

Distal muscles

Somatotopy of grey matter coincides with?

Somatotopy of the white matter
lateral grey matter distal- lateral corticospinal tract distal muscles
anterior grey matter proximal - anterior corticospinal tract proximal muscles

Rubrospinal Tract Origin
Midbrain
Rubrospinal Tract Function
upper extremity flexors
Reticulo-/Vestibulospinal Tract Origin
Pons/medullat
Reticulo-/Vestibulospinal Tract Function
extensor musculature
Cerebrum inhibiting Rubrospinal Tract and Reticulo-/vestibulospinal tracts
this is normal

When Cerebral inhibition is lost on Rubrospinal Tract and Reticulo-/vestibulospinal tracts
- with Rubrospinal Tract causing Arm Flexion
- and
- Reticulo-/vestibulospinal tracts causing leg extension
- this posture is called decorticate posturing

When there is a lesion at or below the midbrain and interrupts Cerebral inhibition of Reticulo-/vestibulospinal tracts but still interrupts the Rubrospinal tract
- Decerebrate Posturing
- Reticulo/vestibulospinal tracts cause neck and limb extension called decerebrate posturing

Rubrospinal Tract Origin
Red nucleus in midbrain
Rubrospinal Tract Termination
Contralateral
crosses in the ventral tegmental area of the brainstem and innervates the upper cervical spinal cord for upper limb flexion
Tectospinal Tract Origin
Superior colliculus of the midbrain
Tectospinal Tract Termination
Contralateral
decussates in the dorsal midbrain tegmentum
Rubrospinal Tract Function
Innervates upper cervical spinal segments to activate neck movements and produce contralateral head turn
Medial Reticulospinal Tract Origin
Medial zone of the pontine reticular formation
Medial Reticulospinal Tract Termination
Terminates ipsilaterally mostly
Medial Reticulospinal Tract function
activate axial and proximal limb extensors
Lateral Reticulospinal Tract Origin
Medullary reticular formation
Lateral Reticulospinal Tract Termination
Bilaterally
Lateral Reticulospinal Tract Function
- inhibits axial and proximal limb extensors
- to a lesser degree it excites axial and proximal flexors
Medial Vestibulospinal Tract Origin
Medial & Spinal vestibular nuclei
Medial Vestibulospinal Tract Termination
Bilateral
Medial Vestibulospinal Tract Function
excite neck extensor musculature
Lateral Vestibulospinal Tract Origin
Medullary reticular formation
Lateral Vestibulospinal Tract Termination
ipsilateral
Lateral Vestibulospinal Tract Function
ipsilateral, perivertebral, and proximal limb extensor muscles
Identify descending spinal tracts

