Spinal Pathways Series: Spinothalamic Tract

Overview

• Third video in the Spinal Pathways series.
• Focuses on the spinothalamic tract.

Spinothalamic Tract Functions

• Conveys sensation of:
  • Pain
  • Temperature
  • Crude touch

Pathway Description

• Start: Begins with nerve endings/receptors in the body.
• Neurons:
  • Pseudo unipolar neurons.
  • Cell bodies located in the dorsal root ganglion.
• Dorsal Column Medial Lemniscus: Similar neural structure as in this pathway.

Pathway Process

1. Entry:

   • Enters the spinal cord.
   • Ascends/descends 1-2 levels within Lissauer's fasciculus.
   • Synapses onto a cell body in dorsal horn of the gray matter.

2. Decussation:

   • Axon crosses (decussates) to the other side.
   • Ascends via the spinothalamic fasciculus.
   • Decussation occurs at the anterior white commissure.

3. Synapse Locations:

   • Neurons located within:
     • Substantia gelatinosa
     • Nucleus proprius

4. Ascending Pathway:

   • Ascends through brainstem.
   • Synapses onto the thalamus.
   • Projects to the postcentral gyrus of the cortex.

Key Characteristics

• Spinothalamic Tract Name:

  • Ascends from spinal cord to thalamus.

• Cortical Projection:

  • Projects to the postcentral gyrus, primary sensory area.
  • Similar projection as the dorsal column medial lemniscus pathway.

Neuron Pathway

• Three-neuron pathway:
  1. First neuron: Dorsal root ganglion.
  2. Second neuron: Dorsal horn of spinal cord.
  3. Third neuron: Thalamus.

Conclusion and Next Steps

• Concludes the spinothalamic tract tutorial.
• Next tutorial: Corticospinal tract (primary motor pathway).

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