taste pathway

Taste pathway
Taste sensation carried by 3 cranial nerves
- From anterior 2/3 of tongue by chorda tympani branch of facial nerve
- posterior 1/3 of tongue by glossopharyngeal nerve
-Most posterior part and epiglottis by internal laryngeal branch of vagus
- The first order neuron which represnted by these 3 cranial nerves end into upper part of nucleus solitarius in Medulla
- Second order neuron starts in nucleus solitarius and mostly crosses to the opposit side to end into VPM nucleus of thalamus
- 3rd order neuron from VPM to insula (gustatory cortical area)
- There is interaction between taste sensation and other cortical area related to olfaction, limbic system and hypothalamus that explains the emotional reaction to taste sensation (Sense of pleasure or disgust).
Abnormalities of taste sensation can be:
1. Ageusia: loss of taste
2. Dysgeusia: abnormal taste sensation
3. Hypogeusia: decreased taste sensation
4. Hyperguesia: Exaggerated taste sensation