Mechanical Whisker Simulation Could Help Better Understand Human Touch

An interdisciplinary team of Northwestern University researchers has developed in a new study -- a pioneering mechanical whisker simulation inside a follicle to give insight into the sense of touch of mammals.

According to a Phys.org article, the base of the whisker, which is accountable for sending touch signals to the brain, is hidden inside the follicle, a deep pocket embedding the whisker within the skin.

Since this whisker's section is hidden, understanding exactly how whiskers communicate touch to their brain has been a long-lasting mystery.

By incorporating their new model with fresh anatomical observations, the study investigators found that when whiskers are touching an object, they form an 'S-shaped' bend within the follicle.

By bending into such a shape, the whisker is pushing or pulling on sensory cells, which then send to the brain the touch signals.

The study entitled, "Constraints on the deformation of the vibrissa within the follicle" is published in the PLOS Computational Biology journal.

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How These New Simulations Help Researchers

The study findings help researchers predict how whiskers are activating different sensory cells to affect which signals are sent to the brain. They help better understand human touch, as well.

According to the study's senior author, Northwestern's Mitra Hartmann, this part of the whisker that stimulates touch sensors are hidden inside the follicle and thus, it is incredibly quite a challenge to study.

Hartmann, who's a biomedical and medical engineering professor at Northwestern's McCormick School of Engineering also said, this process cannot be measured experimentally since if the follicle is sliced open, then, the damage would change the manner the whisker is held.

Through the development of new simulations, researchers can now gain insights into biological processes that cannot be directly quantified experimentally.

Whiskers for Sense of Touch

As indicated in the said information site, most mammals are using whiskers for a sense of touch. Specifically, they use them to explore their environments.

Like human hairs, whiskers do not have sensors along their length. All of their sensors are ate the base in the follicle, instead.

When an external force is bending a whisker, that particular deformation extends along the whisker into the follicle, stimulating sensor cells.

Few earlier studies have investigated how whiskers are deforming within follicles so they can make contact with the sensor cells.

For a better understanding of the process, the research team drew on data from investigational studies of whisker follicles.

Active Whisking and Passive Touch

On top of discovering what the researchers described as a "signature 'S-shaped' bend," the team of Northwestern researchers identified this bending profile is possibly similar regardless if an animal is actively touching an object using its whiskers or is passively touched by something external.

According to the paper's first author, a Ph.D., student in Hartmann's laboratory, Yifu Luo, their model shows consistency in the whisker deformation profile between active whisking and passive touch.

Meaning, the same sensory cell group will react when the whisker is deflected in a similar direction under both circumstances.

This result suggests that some types of investigations to examine active whisking can be done in an anesthetized animal.

In this study, although the model is based on investigational data collected from mice, Hartmann believes the team's findings will likely be applicable to all mammals.

More so, more than discovering more about humans' furry friends, this work could also provide new understandings into the human sense of touch.

Related information about whiskers is shown on BBC Earth's YouTube video below: