Effect of fingerprints orientation on skin vibrations during tactile exploration of textured surfaces

TL;DR

This study investigates how fingerprint orientation affects skin vibrations during tactile exploration, showing that fingerprint alignment influences vibrational signals that are crucial for texture perception.

Contribution

The paper provides experimental evidence that fingerprint orientation modulates skin vibrations, supporting the hypothesis that fingerprints shape tactile signals for better texture discrimination.

Findings

Fingerprint orientation affects vibrational frequency spectra.

Perpendicular fingerprint orientation enhances specific vibrational frequencies.

Results support the role of fingerprints in tactile signal processing.

Abstract

In humans, the tactile perception of fine textures is mediated by skin vibrations when scanning the surface with the fingertip. These vibrations are encoded by specific mechanoreceptors, Pacinian corpuscules (PCs), located about 2 mm below the skin surface. In a recent article, we performed experiments using a biomimetic sensor which suggest that fingerprints (epidermal ridges) may play an important role in shaping the subcutaneous stress vibrations in a way which facilitates their processing by the PC channel. Here we further test this hypothesis by directly recording the modulations of the fingerpad/substrate friction force induced by scanning an actual fingertip across a textured surface. When the fingerprints are oriented perpendicular to the scanning direction, the spectrum of these modulations shows a pronounced maximum around the frequency v/lambda, where v is the scanning velocity and lambda the fingerprints period. This simple biomechanical result confirms the relevance of our previous finding for human touch.