Reticulospinal tract
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Anatomy
- Reticulospinal tract is a descending tract present in the white matter of the spinal cord, originating in the reticular formation
- It is part of the Extrapyramidal system along with Vestibulospinal, Rubrospinal and Tectospinal tracts.
- It consists of bundles of axons that carry information or orders from the reticular formation in the brainstem to the peripheral body parts.
- Reticulospinal tract is responsible primarily for locomotion and postural control.
- Reticulospinal tract is comprised of the
- Medial (pontine) tract: Descends ipsilaterally in the anterior funiculus. Responsible for controlling axial and extensor motor neurons e.g enable extension of the legs to maintain postural support ; Stimulation of the midbrain locomotor centre can result patterned movements (e.g. stepping)
- Lateral (medullary) tract: Descends bilaterally in the lateral funiculus. Responsible for flexor motor neurons ; Inhibits the medial reticulospinal tract and therefore extensor motor neurons enabling modulation of the stretch reflex
Functions
- Motor activity: The reticulospinal tract is one of the most important extra-pyramidal tracts for controlling the activity of lower motor neurons. Its fibers can inhibit or stimulate motor activity.
- Posture Maintenance
- Control of Autonomic Functions such as heart rate, circulation, breathing, respiratory rate
- Control of Sympathetic and Parasympathetic Outflow: (Sacral parasympathetic outflow)
- Locomotion: When generating movements in two sides of the body within humans, it results in reciprocal inhibition of the flexors and extensors.
Spastic paraplegia
- As the lateral reticulospinal's is involved in inhibition, if disrupted it can result in spasticity.
- In addition due to the lack of descending inhibition, the medial reticulospinal tract would then maintain spasticity in the musculature.