Gustatory System Taste

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Gustatory System - Taste

• "Well, Art is Art, isn't it? Still, on the
  other hand, water is water! And East is East and
  West is West and if you take cranberries and stew
  them like applesauce they taste much more like
  prunes than rhubarb does. Now, uh... Now you tell
  me what you know."
• Groucho Marx

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A moment on the lips(and tongue)
Taste buds are aggregations (30-100) of
neuroepithelial cells embedded in specialized
epithelium, termed papillae. Taste receptors do
not have axons. At the base of the taste bud,
signals are conveyed by transmitters to fibers of
cranial nerves VII, IX, and X. These receptors
distinguish between sour, sweet, bitter, and
salty flavors.
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Anatomy of a tongue
Vallate Papilla
Taste Bud
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All roads lead to the CNS

• Cranial Nerves VII, IX, and X carry taste
  information to the rostral medulla.
• The fibers join the Solitary tract in the medulla
  and the central tegmental tract in the pons
• Fibers synapse in the Ventral posterior medial
  nucleus of the Thalamus (Parvocellular division).
• Finally, the fibers leave the VPM and terminate
  on the gustatory cortex in the anterior insula
  and frontal operculum.

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Getting to the medulla
GG Geniculate Ganglion GP Greater
Petrosal n. CT Chordae
Tympani n. IG Inferior Ganglion
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Getting to the cortex
VPM of Thalamus
Gustatory Cortex
Midbrain
Central Tegmental Tract
Pons
Solitary Tract
Medulla
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Can you find the Central Tegmental tract in the
pons?
Click on the picture for the correct answer.
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A closer look at the VPM

• Gustatory information is relayed to the Gustatory
  cortex via the posterior limb of the internal
  capsule from the parvocellular (pale-staining)
  division of the VPM.

Medial Dorsal Nucleus
Gustatory Cortex
Posterior Limb of Internal Capsule
VPL of Thalamus
VPM of Thalamus Medial (parvocellular)
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And now for the movie...