ANAT 321 Lecture Notes - Lecture 8: Cranial Nerve Nucleus, Medial Lemniscus, Spinothalamic Tract

• School: McGill University
• Department: Anatomy & Cell Biology
• Course: ANAT 321
• Professor: David Ragsdale

Document Summary

Diff pathways (e. g. dorsal column-medial lemniscal & anterolateral; bundles of fibres on way to thalamus) Spinothalamic tract: anterolateral pathway; starts in spinal cord to thalamus. Anterolateral pathway also make synapses in brainstem: effective & arousing aspects of pain. Know location of pain: spinothalamic tract; to primary somatosensory cortex, has detailed map of body surface. Grey matter stained light, white matter stained dark. Dorsal column progressively replaced by nuclei (nucleus gracilis & cuneatus); end points of fine touch/proprioceptive projections. Fine touch & prop cross sides in nucleus. Ridge at top of spinal cord opens up. 2 dark bands: medial lemniscus for opposite side of body up to thalamus. Fibres from 2nd order neurons crossing sides in 2 nuclei (dorsal column medial lemniscus pathway) Somatotopic organization maintained (all the way up to primary somatosensory cortex) Cerebral aqueduct: connects 4th ventricle to 3rd ventricle. Spinothalamic tract all the way up to thalamus. 2 main pathways: both originate in motor cortex (front of brain)