Podcast
Questions and Answers
Which of the following is characteristic of the Dorsal Spinocerebellar Tract (DSCT)?
Which of the following is characteristic of the Dorsal Spinocerebellar Tract (DSCT)?
- Decussates twice, resulting in contralateral ataxia after the second decussation.
- Consists of three neurons in its pathway from the spinal cord to the cerebellum.
- Primarily involved in controlling flexor muscles of the upper limb.
- Ascends ipsilaterally and does not decussate, leading to ipsilateral ataxia upon lesion. (correct)
A patient presents with contralateral ataxia following a spinal cord lesion. Which tract might be affected?
A patient presents with contralateral ataxia following a spinal cord lesion. Which tract might be affected?
- Ventral Spinocerebellar Tract (VSCT) below the second decussation. (correct)
- Reticulospinal Tract.
- Dorsal Spinocerebellar Tract (DSCT).
- Vestibulospinal Tract.
The Ventral Spinocerebellar Tract (VSCT) decussates twice. What is the functional significance of this double decussation?
The Ventral Spinocerebellar Tract (VSCT) decussates twice. What is the functional significance of this double decussation?
- It results in contralateral control of motor function.
- It allows for fine motor control of distal muscles.
- It makes the tract functionally ipsilateral. (correct)
- It increases the speed of signal transmission to the cerebellum.
Damage to the lateral vestibulospinal tract would most likely result in:
Damage to the lateral vestibulospinal tract would most likely result in:
A patient exhibits ipsilateral loss of balance and a tendency to fall towards the side of a lesion. Which tract is most likely affected?
A patient exhibits ipsilateral loss of balance and a tendency to fall towards the side of a lesion. Which tract is most likely affected?
Which of the following is a key characteristic of the reticulospinal tract's influence on motor function?
Which of the following is a key characteristic of the reticulospinal tract's influence on motor function?
A patient presents with spasticity and hyperreflexia after a neurological event. Damage to which descending tract might contribute to these symptoms?
A patient presents with spasticity and hyperreflexia after a neurological event. Damage to which descending tract might contribute to these symptoms?
Following a stroke, a patient exhibits contralateral flexor weakness in the upper limb. Which tract is most likely affected by a lesion above its decussation?
Following a stroke, a patient exhibits contralateral flexor weakness in the upper limb. Which tract is most likely affected by a lesion above its decussation?
What would be the most likely presentation of a patient with damage to the Rubrospinal tract below the decussation in the spinal cord?
What would be the most likely presentation of a patient with damage to the Rubrospinal tract below the decussation in the spinal cord?
Which of the following tracts does NOT decussate?
Which of the following tracts does NOT decussate?
Flashcards
Dorsal Spinocerebellar Tract (DSCT)
Dorsal Spinocerebellar Tract (DSCT)
Two neurons; 1st synapses in Clarke's nucleus (T1-L2); axons ascend ipsilaterally.
Ventral Spinocerebellar Tract (VSCT)
Ventral Spinocerebellar Tract (VSCT)
Two neurons; axons decussate in spinal cord, ascend contralaterally, then decussate again in cerebellum.
Vestibulospinal Tract
Vestibulospinal Tract
Two neurons; 1st cell body in vestibular nuclei; axons descend ipsilaterally; postural control.
Reticulospinal Tract
Reticulospinal Tract
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Rubrospinal Tract
Rubrospinal Tract
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Ipsilateral Ataxia
Ipsilateral Ataxia
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Ventral Spinocerebellar Tract Lesion
Ventral Spinocerebellar Tract Lesion
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Study Notes
- All tracts are white matter tracts
Dorsal Spinocerebellar Tract(DSCT)
- Pathway contains 2 neurons
- First-Order Neuron: Cell body is located in the Dorsal root ganglion (DRG)
- Synapses occur in Clarke's nucleus (nucleus dorsalis) in the spinal cord (T1-L2)
- Second-Order Neuron: Cell body is located in Clarke's nucleus
- Axons ascend ipsilaterally through the inferior cerebellar peduncle to the cerebellum.
- Does NOT decussate; remains ipsilateral
- Lesion causes ipsilateral ataxia and loss of unconscious proprioception below the lesion
Ventral Spinocerebellar Tract (VSCT)
- Pathway contains 2 neurons
- First-Order Neuron: Cell body is located in the Dorsal root ganglion (DRG)
- Synapses occur in Spinal border cells in the dorsal horn (L3-L5)
- Second-Order Neuron: Cell body is located in Spinal border cells
- Axons decussate in the spinal cord, ascend contralaterally, then decussate again in the cerebellum before entering via the superior cerebellar peduncle.
- Decussates twice, once in the spinal cord and again in the cerebellum (making it functionally ipsilateral).
- Spinal Cord Lesion (Below Second Decussation) results in Contralateral ataxia
- Lesion Above Second Decussation (Brainstem/Cerebellum) results in Ipsilateral ataxia
Vestibulospinal Tract
- Pathway contains 2 neurons
- First-Order Neuron: Cell body: Located in Vestibular nuclei in the brainstem (medulla/pons)
- Axons descend ipsilaterally
- Two divisions: Lateral vestibulospinal tract goes to entire spinal cord (postural control)
- Medial vestibulospinal tract goes to cervical and upper thoracic cord (head/eye coordination)
- Second-Order Neuron: Cell body: Located in Ventral horn of spinal cord
- Synapses on lower motor neurons controlling extensor muscles
- No decussation; remains ipsilateral
- Lesion results in ipsilateral loss of balance and posture, causing falling towards the side of the lesion
- Head tilt will occur if medial vestibulospinal tract is affected
Reticulospinal Tract
- Pathway contains 2 neurons
- First-Order Neuron: Cell body: Located in Reticular formation(medial tract(pons) or lateral tract(medulla))
- Axons descend mostly ipsilaterally but with some bilateral influence
- Second-Order Neuron: Cell body: Located in Ventral horn of the spinal cord
- Synapses on motor neurons controlling postural and locomotor muscles
- Mostly ipsilateral; No decussation; some fibers have bilateral influence
- Lesion Results: Loss of postural control, spasticity & hyperreflexia (if descending inhibition is lost)
- Bilateral damage can lead to decerebrate rigidity
Rubrospinal Tract
- Pathway contains 2 neurons
- First-Order Neuron: Cell body: Located in Red nucleus (midbrain)
- Axons immediately decussate and descend in the lateral spinal cord
- Second-Order Neuron: Cell body: Located in Ventral horn of the spinal cord
- Synapses on motor neurons controlling flexor muscles of the upper limb
- Decussates in the midbrain (ventral tegmental decussation)
- Lesion Above Decussation (Midbrain/Brainstem Lesion): Contralateral flexor weakness
- If corticospinal tract is also damaged, decerebrate rigidity(extensor posturing) can also occur
- Lesion Below Decussation (Spinal Cord Lesion): Ipsilateral flexor weakness
- May contribute to spasticity if damaged along with corticospinal tract
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