Trigeminal Perception

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Under trigeminal perception refers to the sensory stimuli that over the trigeminal nerve are taught.

backgrounds

The facial nerve trigeminal nerve conveys tactile sensations of the facial region and is involved in the perception of scents, which is why one speaks of gustatory, olfactory and trigeminal perception. It is now assumed that the trigeminal nerve is mainly used to perceive properties such as burning, sharp, astringent , tingling, biting, tingy, stinging, cooling (generally irritating properties).

No specific sensory cells can be assigned to the trigeminal nerve. The stimulus is picked up in the free, sensitive end areas of the trigeminal neuron . Free nerve endings that respond to chemical stimuli are found in the eye and in the mucous membranes of the nasal and oral cavities . In the fungal papillae on the surface of the tongue there are three times more connections to the trigeminal nerve than to fibers of the gustatory system.

Onion causes tear secretion through the ophthalmic nerve , ammonia , hydrochloric acid irritation through the nose, the maxillary nerve is primarily irritated by sharp ( piperine , capsaicin ). The reactions are different: tear secretion , saliva secretion , reflex interruption of the breathing rhythm, sneezing reflex . Nasal trigeminal fibers also react to the majority of olfactory olfactory substances, but only at higher (not yet irritating) concentrations than the olfactory nervous system. The trigeminal nerve therefore makes a significant contribution to the intensity of smell sensitivity (30%). The hedonic evaluation of trigeminal stimuli is ambivalent ( blood , sperm ), or on the one hand positive ( flowers , mustard , horseradish , menthol , carbon dioxide , alcohol , onion ), on the other hand very negative ( feces , ammonia, smoke ).

The oral-trigeminal system has been less studied than the nasal-trigeminal system. Nerve endings are found all over the mouth, including fungal papillae. The reflex activity is limited to increasing the flow of saliva. There is no evidence that the oral-trigeminal system contributes to gustatory sensation. Oral trigeminal stimulation persists for some time after the stimulation (sensory perseveration ). Temperature illusions are warm and cold sensations that are triggered by chemical stimuli (also present in a weakened form in the nasal-trigeminal system). Frequent irritation leads to a decrease in sensitivity ( pepper , hot spices ). Learning and conditioning processes are probably responsible for the preference for hot spices ( endorphin production , saliva production).

See also

• perception

Individual evidence

1. ↑ Jennifer Spehr: Molecular Mechanisemen of the Chemoreception of Trigeminal Neurons in Mammals. Accessed: August 11, 2014 (dissertation).
2. ^ Dennis Shusterman: Qualitative Effects in Nasal Trigeminal Chemoreception. In: Annals of the New York Academy of Sciences 2009, 1170, pp. 196-201. PDF ( Memento of the original from July 21, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
3. ↑ Thomas Hummel, Andrew Livermore: Intranasal chemosensory function of the trigeminal nerve and aspects of its relation to olfaction. In: International Archives of Occupational and Environmental Health 2002, Volume 75, Issue 5, pp. 305-313. PDF