Slide 33: Sensory Decussation Level

Identify:

• Pyramidal Tract (PT)
• Medial Lemniscus (ML)
• Tectospinal Tract (TST)
• Medial Longitudinal Fasciculus (MLF)
• Spinal Trigeminal Nucleus and Tract (SpTN, SpTTr)
• Principal Olive (PO), Dorsal Accessory Olive (DAO), Medial Accessory Olive (MAO)
• Medial and Spinal Vestibular Nuclei (MVN, SpVN)
• Inferior Cerebellar Peduncle (ICP)
• Hypoglossal Nuclei (12)
• Dorsal Motor Nucleus (DMN)
• Solitary Tract and Nucleus )SN)
• Nucleus Ambiguus (NA)
• Dorsal and Ventral Spinocerebellar Tracts (DSCT, VSCT)
• Spinothalamic Tract (STT)
• Rubrospinal Tract (RST)
• Hypothalamo-Autonomic Tract (HAT)

Note:

• The Spinal Vestibular Nuclei has a peppered appearance due to vestibulospinal fibers running through it.
• The Nucleus Ambiguus primarily innervates branchial arch musculature of the pharynx, esophagus, and larynx (SVE). However, it also gives rise to vagal preganglionic parasympathetic (GVE) projections to the heart, similar to the Dorsal Motor Nucleus.
• The Vagus Nerve is associated with four nuclei:
  • Dorsal Motor Nuclei - GVE
  • Nucleus Ambiguus - SVE (brachial arch muscles)
  • Solitary Nucleus - GVA (majority) and SVA (some taste buds)
  • Spinal Trigeminal Nucleus - GSA (portion of external ear)