Somatosensory Pathways

Comparing the medial lemniscus (dorsal column) system with the anterolateral system. 

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Somatosensory Pathways

Similarities

  • The dorsal column and anterolateral systems are both somatosensory pathways which convey sensory information from the neck, upper limbs and upper trunk
  • Both have their second synapse with the VPL nucleus in the thalamus
  • Both have their third synapse with the primary somatic sensory cortex in the cerebral cortex
  • Both systems have three synapses and are contralateral
  • Both systems become contralateral following their first synapse

Differences

  • The dorsal column system conveys information about fine (discriminative) touch, proprioception and vibration whereas the anterolateral system which conveys information about pain, temperature, crude touch and pressure.
  • The dorsal column system contains fast primary afferents whereas the anterolateral system contains slow primary afferents
  • The first synapse of the dorsal column system is with the medulla whereas the anterolateral system synapses with a lamina V cell in the spinal cord
  • The dorsal column system has to contributing fasciculi, the cuneate fasciculus and the gracile fasciculus, whereas the anterolateral system just has the anterolateral fasciculus. The two fasciculi of the dorsal column system converge to form the medial lemniscus
  • The dorsal column system becomes contralateral after it synapses with the medulla whereas the anterolateral system becomes contralateral in the spinal cord

Overall comparison

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