The role of body mechanics in touch sensation in the nematode Caenorhabditis elegans
Abstract/Contents
- Abstract
- The mechanics of our skin determine how our skin and specialized mechanically-sensitive neurons within it are stressed and strained when touched. Understanding the interplay between skin mechanics and touch sensitivity is paramount in uncovering the fundamental molecular mechanisms underlying touch sensation and in understanding and treating touch insensitivity due to diseases like peripheral neuropathy. Despite this importance, the interplay between skin mechanics and sensitivity is poorly understood. The organism Caenorhabiditis elegans is an excellent model system in which to test the hypothesis that skin mechanics affect touch sensitivity. C. elegans detects body touch with just six mechanically-sensitive neurons. These neurons are embedded in the outer shell (consisting of the cuticle, hypodermis and body wall muscles) of the body plan, which dominates the overall body mechanics. If skin mechanics are important in touch sensitivity in C. elegans, stiffening or softening the outer shell should alter the ability of the animal to detect applied mechanical stimuli. I demonstrate that a piezoresistive cantilever force clamp system and methods that alter C. elegans body mechanics can be combined to directly test the hypothesis that mechanics modulate touch sensitivity. In particular, I build on prior work demonstrating that genetic mutation of cuticle proteins alters body stiffness, and use optogenetic modulation of body wall muscle tone to demonstrate that the body wall muscles modulate C. elegans body mechanics. Combining piezoresistive cantilevers capable of applying minute forces with these techniques to alter the mechanics of the body allows us to directly quantify the affect of body stiffening or softening on force or indentation depth sensitivity in C. elegans. I find that even small shifts in body stiffness have a significant effect on force sensitivity, with body stiffening leading to a reduction in force sensitivity and vice versa. Further, I demonstrate that indentation depth sensitivity is less affected by changes in body mechanics, suggesting that the mechanically-sensitive neurons involved in body touch in C. elegans respond more directly to applied indentation than to applied force. These findings emphasize the importance of considering skin mechanics in understanding the sense of touch and insensitivity due to diseases like peripheral neuropathy.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Petzold, Bryan Carl |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering |
| Primary advisor | Pruitt, Beth |
| Thesis advisor | Pruitt, Beth |
| Thesis advisor | Dunn, Alexander Robert |
| Thesis advisor | Goodman, Miriam Beth |
| Advisor | Dunn, Alexander Robert |
| Advisor | Goodman, Miriam Beth |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Bryan Carl Petzold. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Bryan Carl Petzold
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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