Reticulospinal Tract

Original Editor -
Kate Sampson

Top Contributors - Kate Sampson, Lucinda hampton, 127.0.0.1, Wendy Walker, Evan Thomas, WikiSysop and Kim Jackson

Description

The Reticulospinal tract is responsible primarily for locomotion and postural control. The Reticulospinal tract is comprised of the medial (pontine) tract and the lateral (medullary) tract.

Anatomy

Origin

- Reticular formation in the pontine (Medial Reticulospinal tract) and medulla (Lateral Reticulospinal tract)

Course / Path

Medial Reticulospinal Tract (Pontine)

- Descend ipsilaterally in the anterior funiculus.

Lateral Reticulospinal tracts(Medullary)

- Descend bilaterally in the lateral funiculus.

Both the lateral and medial tracts act via internuncials shared with the corticospinal tract on proximal limb and axial muscle motor neurons

Function

- Control activity of both alpha and gamma motor neurones.

- Mediate pressor and depressor effects on the circulatory system.

- Help to control breathing 0

- Due to the interrelation between vestibulospinal and ipsilateral reticulospinal tracts this can result in selective activation of many muscles at the same time. As they work through interneurones and long propriospinal neurons it can enable co-ordinated, selective movements.

- The relationship between the rubrospinal and crossed reticulospianl tracts can result in a postural role within distal musculature. The pathways innervate motorneurones both directly and indirectly through interneurons and short propriospinal neurons. E.G intrinsics acting in a postural role for individual finger movement.

Medial Reticulospinal Tract (Pontine)

- Responsible for controlling extensor motor neurons

- Stimulation of the midbrain locomotor centre can result patterned movements e.g. stepping

Lateral Reticulospinal Tract (Medullary)

- Responsible for flexor motor neurons.

Locomotion

Within humans when generating movements in two sides of the body it results in reciprocal inhibition of the flexors and extensors.

In animal studies central pattern generators are found to be responsible for locomotion generation. As locomtorion is generated by internuncial neurons in the Cx and Lx activating the flexors and extensors the intermediate gray matter is able to initiate rhythmical movements.

In humans locomotion is generated in the locomotion centre in the midbrain. The premotor cortext which is responsible for the overarching control of locomotion projects to the brainstem and therefore reticulospinal tract.  As a consequence the reticulospinal tract is able to modulate control of locomotion. The reticular formation due to its role in attention and consious perception can result in a specific reaction to sensory information. The cortico-reticulospinal tract is thereby responsible for transmitting excitatory and inhibitory information and to be processed before being passed to the spinal cord.

Posture

The reticular formation within the pons is partly responsible for postural control functions.

The premotor cortex is able to identify appropriate axial musculature to enable distal movement. Due to the interpolatin of internuncial neuros between the corticospinal and reticulospinal tracts, this means that either pyramidial or extrapyramidial tracts can be responsible for controlling movement patterns. The extrapyramidial system (reticulospinal) tract can initiate movement within a stable, routine situation, whereas the pyramidial (corticospinal) tract is able to control tasks requiring more cognitive appraisal e.g. varying surface, distractions and requiring close attention.

Pathology

Leisons to the cortico-reticulospinal system can result in decreased postural control and reduced selectivity of postural conrol.

Recent Related Research (from Pubmed)

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References

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