Neuroscience: Spinal Cord Tracts Overview

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Questions and Answers

What typically causes Central Cord Syndrome?

Occlusion of the anterior spinal artery

Penetrating injuries to the spine

Trauma resulting from a fall

A syrinx in the spinal cord (correct)

What type of deficits are expected with anterior cord syndrome?

Deficits below the level of injury affecting proprioception

Only sensory deficits at the level of injury

Loss of motor function and pain sensation below the injury (correct)

Deficits exclusively at the injury level

Which statement correctly describes Brown-Sequard syndrome?

It causes bilateral loss of sensation and motor function.

It results from occlusion of the posterior spinal artery.

It is most commonly caused by a syrinx in the spinal cord.

It leads to unilateral deficits in motor control and sensation. (correct)

What are the implications of grey matter involvement in spinal cord injuries?

Symptoms typically vary depending on the size of the injury. Signup and view all the answers

What underlying condition usually causes posterior cord syndrome?

Occlusion of the posterior spinal artery Signup and view all the answers

Which area does the Lateral Corticospinal Tract decussate?

Cervicomedullary junction Signup and view all the answers

What is a characteristic feature of the Medial Corticospinal Tract?

It synapses in the anterior column of the spinal cord. Signup and view all the answers

What does the Anterior (Medial) Corticospinal Tract primarily control?

Muscles in the neck, shoulder, and trunk. Signup and view all the answers

Which of the following is true regarding the course of the Lateral Corticospinal Tract?

It passes through the internal capsule. Signup and view all the answers

What percentage of the total corticospinal tract is composed of the Medial (Anterior) Corticospinal Tract?

10 % Signup and view all the answers

What is the primary function of ascending tracts in the spinal cord?

To transmit sensory information to the brain Signup and view all the answers

Which of the following tracts are classified as lateral pathways?

Corticospinal and Rubrospinal Signup and view all the answers

What is the role of the rubrospinal tract?

To transmit motor signals related to voluntary movement Signup and view all the answers

How do the Dorsal Column and Anterolateral pathways compare in terms of function?

Both communicate with contralateral thalamic nuclei and somatosensory cortex Signup and view all the answers

What does the term 'funiculus' refer to in the context of spinal cord anatomy?

A column of bundled nerve fibers Signup and view all the answers

In spinal cord anatomy, what are fasciculi?

Small bundles of nerve fibers Signup and view all the answers

Which spinal cord tract is involved in maintaining posture and balance?

Vestibulospinal tract Signup and view all the answers

Where do the majority of descending tracts in the spinal cord originate?

In the brainstem and cerebral cortex Signup and view all the answers

What is the primary function of the Dorsal Column Medial Lemniscus pathway?

Proprioception and discriminative touch Signup and view all the answers

Which tract is primarily responsible for conveying unconscious proprioceptive information?

Spinocerebellar Tract Signup and view all the answers

Which structure is associated with fine, precise motor skills in distal extremities?

Lateral Corticospinal Tract Signup and view all the answers

How are pain and temperature sensations initially processed in the spinal cord?

They synapse on interneurons in the dorsal horn. Signup and view all the answers

What is the key concept of information organization mentioned in relation to the Dorsal Column pathways?

Somatotopic organization Signup and view all the answers

Which pathway is responsible for trunk movement and proximal muscle control?

Medial System Signup and view all the answers

Which tract contains 90% of the fibers associated with voluntary movement?

Lateral Corticospinal Tract Signup and view all the answers

What function is primarily associated with the Anterolateral Spinothalamic pathway?

Sharp pain sensation, temperature, and crude touch Signup and view all the answers

What is the origin of the Rubrospinal tract?

Red nucleus of the midbrain Signup and view all the answers

Which tract is primarily responsible for maintaining standing posture?

Reticulospinal Tract (Pontine) Signup and view all the answers

Which function is associated with the Vestibulospinal Tract?

Maintains head positioning during movement Signup and view all the answers

Which characteristic describes the Lateral Corticospinal and Rubrospinal impairments?

Poor Fractionated Movements of arms and hands Signup and view all the answers

What type of sensory information do the Vestibular nuclei integrate?

Sensory information on head position and movement Signup and view all the answers

The Tectospinal tract is primarily involved in responding to what type of stimuli?

Visual and auditory stimuli Signup and view all the answers

Damage to which tracts is likely to lead to ataxia and balance problems?

Vestibulospinal tracts Signup and view all the answers

Which tract helps to liberate antigravity muscles from reflex control?

Reticulospinal Tract (Lateral) Signup and view all the answers

Which pathway originates from the red nucleus and decussates in the pons?

Rubrospinal Tract Signup and view all the answers

What is a key function of the Pontine Reticulospinal tract?

Facilitates extensor motor neurons Signup and view all the answers

Study Notes

White Matter

Comprised of axon columns in the spinal cord.
Contains ascending tracts that transport sensory information to the brain.
Includes descending tracts carrying motor signals from the brain to the body.
Funiculus refers to a column of nerve fibers; fasciculus denotes smaller bundles.

Spinal Cord Tracts

Ascending tracts include Anterolateral, Spinothalamic, Dorsal Column Medial Lemniscus, and Spinocerebellar tracts.
Descending tracts (motor) include Lateral Corticospinal, Rubrospinal, Reticulospinal, Vestibulospinal, and Tectospinal tracts.

Dorsal Column and Anterolateral Pathways

Both pathways convey sensory information to contralateral thalamic nuclei and somatosensory cortex.
Differences lie in their synapsing structures, crossing points, and anatomical locations of pathways.

Dorsal Column Medial Lemniscus

Function includes proprioception and discriminative touch.
Features Fasciculus gracilis for lower extremities and Fasciculus cuneatus for upper extremities.
Ascends to the medulla, where it transitions to the medial lemniscus.

Anterolateral Pathway

Responsible for transmitting pain, temperature, and crude touch.
Sensory neurons synapse in the dorsal horn of the spinal cord and decussate immediately.
Projects directly to the thalamus.

Spinocerebellar Tract

Involved in conveying unconscious proprioceptive information.

Descending Pathways

Lateral System: Focuses on precise motor skills in distal limbs, includes Lateral Corticospinal and Rubrospinal tracts.
Medial System: Controls trunk movements and proximal muscle coordination through Reticulospinal, Vestibulospinal, and Tectospinal tracts.

Lateral Corticospinal Tract

Comprises 90% of corticospinal fibers; enables fine control of distal extremities.
Facilitates movement fractionation, essential for intricate tasks like typing and playing instruments.

Medial (Anterior) Corticospinal Tract

Represents 10% of corticospinal fibers; originates from the motor cortex.
Does not decussate, controls neck, shoulder, and trunk muscles.

Rubrospinal Tract

Originates from the red nucleus; regulates upper extremity movement.
Decussates in the pons, joins corticospinal tract axons in the lateral spinal cord.

Impairments and Function

Lateral system damage leads to poor control over fine movements and slower, less accurate voluntary actions.
Medial system supports posture and broad movement patterns.

Reticulospinal Tract

Integrates with the reticular formation; aids in arousal and pain modulation.
Facilitates extensor or flexor motor neurons based on the specific tract (Pontine or Lateral).

Vestibulospinal Tract

Integrates sensory inputs on head position and balance.
Medial tract stabilizes head movement, while lateral facilitates extensor function.

Tectospinal Tract

Coordinates reflexive head movements based on visual and auditory stimuli.
Arises from the superior colliculus in the midbrain.

Vascular Supply

Anterior spinal artery and two posterior arteries provide blood supply to the spinal cord.
Segmental vascular supply through spinal artery plexus supports distinct regions.

Spinal Cord Injury Syndromes

Central Cord Syndrome leads to variable impairments depending on white matter or gray matter involvement.
Anterior Cord Syndrome often results from anterior spinal artery occlusion.
Brown-Sequard syndrome results from a unilateral injury causing a distinct pattern of deficits.
Posterior Cord Syndrome is linked to occlusion of the posterior spinal artery, affecting specific tracts based on lesion location.

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Description

Explore the intricate structures of white matter in the spinal cord, including detailed pathways of both ascending and descending tracts. Understand key functions and differences between major tracts such as the Dorsal Column and Anterolateral pathways. This quiz will test your knowledge of fundamental neuroscience concepts.