The Role of Fingerprints in the Coding of Tactile Information Probed with a Biomimetic Sensor

TLDR

In humans, fine texture perception (spatial scale < 200 µm) relies on skin vibrations generated as the finger scans a surface. The study aims to relate texture characteristics to subcutaneous vibrations by employing a biomimetic tactile sensor that matches fingertip dimensions. The sensor scans surfaces, producing skin‑like vibrations that reflect the underlying texture. When the sensor surface is patterned with fingerprint‑like ridges, the vibration spectrum is dominated by a frequency set by the scanning speed and ridge spacing, which falls within the optimal sensitivity range of Pacinian afferents, indicating that fingerprints may act as spectral selectors that amplify tactile information for fine texture coding.

Abstract

In humans, the tactile perception of fine textures (spatial scale &lt;200 micrometers) is mediated by skin vibrations generated as the finger scans the surface. To establish the relationship between texture characteristics and subcutaneous vibrations, a biomimetic tactile sensor has been designed whose dimensions match those of the fingertip. When the sensor surface is patterned with parallel ridges mimicking the fingerprints, the spectrum of vibrations elicited by randomly textured substrates is dominated by one frequency set by the ratio of the scanning speed to the interridge distance. For human touch, this frequency falls within the optimal range of sensitivity of Pacinian afferents, which mediate the coding of fine textures. Thus, fingerprints may perform spectral selection and amplification of tactile information that facilitate its processing by specific mechanoreceptors.