# SNI - thermal vs mechanical

**URL:** <https://forum.painresearcher.net/t/sni-thermal-vs-mechanical/1034>\
**Category:** General\
**Created:** [November 18, 2022, 9:54pm UTC](https://forum.painresearcher.net/t/sni-thermal-vs-mechanical/1034 "2022-11-18T21:54:15Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ShanTan](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.painresearcher.net/shantan/32/242_2.png) [@ShanTan](https://forum.painresearcher.net/u/ShanTan)\
**Post date:** [November 18, 2022, 9:54pm UTC](https://forum.painresearcher.net/t/sni-thermal-vs-mechanical/1034/1 "2022-11-18T21:54:15Z")

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Is there literature/can someone explain to me why we don’t see thermal hypersensitivity after SNI, but we see mechanical? Never understood why we wouldn’t see both. Thanks!

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**Author:** ![achamess](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.painresearcher.net/achamess/32/534_2.png) [@achamess](https://forum.painresearcher.net/u/achamess)\
**Post date:** [November 25, 2022, 5:38pm UTC](https://forum.painresearcher.net/t/sni-thermal-vs-mechanical/1034/2 "2022-11-25T17:38:41Z")

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Well by thermal do you mean any temperature, or just warm/hot?  
They do have cold hypersensitivity

> **[Mechanistic Differences in Neuropathic Pain Modalities Revealed by...](https://www.sciencedirect.com/science/article/pii/S2211124718300068)**
>
> Chronic neuropathic pain is a major morbidity of neural injury, yet its mechanisms are incompletely understood. Hypersensitivity to previously non-nox…

If you’re asking why not hypersensitivity to warming/heating, probably because whatever neuronal population or mechanism is responsible for that attribute is not induced in SNI. Perhaps others will have a better explanation @thicunha

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**Author:** ![thicunha](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.painresearcher.net/thicunha/32/386_2.png) [@thicunha](https://forum.painresearcher.net/u/thicunha)\
**Post date:** [November 25, 2022, 6:09pm UTC](https://forum.painresearcher.net/t/sni-thermal-vs-mechanical/1034/3 "2022-11-25T18:09:03Z")

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The diference in neuronal population is one possible explanation, but why cold responsive neurons are but not heat encoding neurons are not sensitized is not clear. I also believe that SNI hypersensitivity (ate least in the Sural innervating region) is mainly due to central processes (spinal cord mechanisms/ maybe DRGs mechanism), whereas thermal hypersensitivity is normally a peripheral mechanism. @tberta @jmogil