Characterizing the mechanism of sensorial perception of biomechanical changes in human skin
Abstract/Contents
- Abstract
- The mechanism by which humans perceive biomechanical changes in the outer layer of their skin, the stratum corneum (SC), has not been previously described. The SC, consisting of a network of lipids and corneocytes, interacts with the external environment and its mechanical behavior is sensitive to these interactions. Solar damage, low relative humidity, and damaging topical treatments cause water loss and shrinkage of the SC. Volume changes in the SC result in the development of tensile stresses in the SC, which are perceived as skin tightness. This dissertation first elucidates the mechanism by which SC stresses are transduced by cutaneous mechanoreceptors and their corresponding neurons by demonstrating computationally how stresses in the SC cause the propagation of strains to underlying skin where cutaneous mechanoreceptors reside. A relationship between strain and firing rate of slowly adapting type I (SAI) neurons is used to predict neural activity from computed strains in various skin morphologies. The effects of SC stresses induced by cleansers and moisturizers, which are quantified experimentally, are simulated to predict neural activity specific to each cleanser and moisturizer. A strong linear trend is observed between predicted SAI activity from each topical treatment and skin tightness perception scores reported in a large clinical survey. Next, this dissertation explores the effect of skin layer mechanical properties, skin layer thicknesses, and skin surface topographies on the magnitudes of computed SAI neuron firing rates. Each of these parameters is found to influence the predicted SAI neuron firing rates. Additionally, parameters affecting sensitivity in SAI neuron firing rates to distinct SC contraction amounts are investigated. The topography of the skin surface was found to be especially influential in these studies of sensitivity. Finally, this dissertation evaluates whether it is expected that an individual would maintain the ability to distinguish the unique effects of cleanser and moisturizer treatments when a full thickness skin tensile strain is combined with the SC contractions induced by the topical treatments. This is studied in three distinct skin regions, and it is concluded that the perceptual acuity would be maintained with a stretching of the skin for skin sections with a topography that is not relatively flat. This additional scenario strengthens the conclusion that individuals are capable of perceiving biomechanical changes in the SC through activation of SAI neurons. Overall, this dissertation details the mechanism by which mechanical changes in the SC are perceived and describes relevant parameters for this perception. This provides novel information for the perception of skin tightness, which is not characterized in detail in literature.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2022; ©2022 |
| Publication date | 2022; 2022 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Pace, Joseph |
|---|---|
| Degree supervisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Dauskardt, R. H. (Reinhold H.) |
| Thesis advisor | Chaudhuri, Ovijit |
| Thesis advisor | Goodman, Miriam Beth |
| Degree committee member | Chaudhuri, Ovijit |
| Degree committee member | Goodman, Miriam Beth |
| Associated with | Stanford University, Department of Mechanical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Joseph Pace. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2022. |
| Location | https://purl.stanford.edu/dx892wz4784 |
Access conditions
- Copyright
- © 2022 by Joseph Pace
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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