Spinal Tract Pathways Flashcards
What information is conveyed by the spinothalamic tract?
Non discriminatory touch, temperature and pain
Name all of the sensory tracts.
- Spinothalamic
- Dorsal Column / Medial Leminiscal
- Chief Sensory Tract
- Spinal Tract V
- Spinocerebellar
What information is conveyed by the dorsal column / medial leminiscal tract?
Discriminatory touch, vibration and conscious proprioception
What information is conveyed by the chief sensory tract?
Discriminatory touch, vibration and conscious proprioception
What information is conveyed by the spinal tract V?
Non discriminatory touch, temperature and pain
What information is conveyed by the spinocerebellar tract?
Unconscious proprioception
Name all of the motor tracts.
- Corticospinal tract (pyramidal)
- Corticobulbar tract
- Vestibulospinal tract (extra pyramidal)
- Reticulospinal tract (extra pyramidal)
- Rubrospinal tract (extra pyramidal)
- Tectospinal tract (extra pyramidal)
What is the function of the vestibulospinal tract?
maintenance of posture by innervating extension muscle groups responding to gravity
What is the function of the reticulospinal tract?
- Motor function - selectively inhibits/excites muscle groups to ensure correct tone and correct force depending on the movement e.g walking. Ensures fluidity and smoothness of muscle.
- Sympathetic outflow to the paravertebral chain
- Pain modulation
Describe how motor information is conveyed through the reticulospinal tract.
- Caudal pontine reticular nucleus and oral pontine reticular nucleus extend axons through the medial reticulospinal tract (bilateral) and the gigantocellular nucleus extends axons through the lateral reticulospinal tract (ipsilateral)
- Lateral reticulospinal tract neurons inhibit cortically induced movement of axial extensor muscles
- Medial reticulospinal tract neurons facilitate cortically induced movement of extensor ‘anti-gravity’ muscles
Describe the journey of sympathetic outflow through the reticulospinal tract.
- Nuclei within the hypothalamus extend axons carrying sympathetic information through the dorsal longnitudinal fasiculus to the reticular formation to synapse.
- Neurons from the reticular formation extend through the lateral reticulospinal tract (ipsilateral)
- These synapse at the intermediolateral nucleus. Then there is outflow to the sympathetic chain.
What is the function of the rubrospinal tract?
Fine motor control of flexors mainly of the hand and arms.
Describe the how pain modulation occurs via the reticulospinal tract.
- PAG nuclei extend axons to the reticular formation. These then synapses at the raphe nucleus within the reticular formation.
- Neurons extend through the lateral reticulospinal tract (ipsilateral tract) and synapse at the intermediolateral tract.
- Interneuron then synapses at neurons entering the spinothalamic tract (non-discriminatory touch, temperature and pain) and modulate sensory pain information
Where does the rubrospinal tract originate?
The red nucleus at the midbrain at the level of the superior colliculus
Describe the journey of the rubrospinal tract.
The rubrospinal tract closely resembles the corticospinal tract due the cortical input. This is the only extra-pyramidal tract to do so.
- The motor cortex inputs to the red nucleus (the corticospinal tract iis parallel to the rubrospinal tract, there is a close association)
- The dentate nucleus of the cerebellum also input to the red nucleus. Fibres exit the cerebellum via the superior cerebellar peduncle.
- From the red nucleus, there is immediate decussation.
- The fibers pass through the lateral funiculus (into white mater) and pass into the grey matter where it synapses with lower motor neurons.
- These lower motor neurons innervate flexors and extensors but mainly flexors for fine motor control.
- This terminates mainly at the cervical spinal levels for extra dexterity of the arms and hands