Pacinian corpuscles are the principal detectors of high-frequency vibrations in amniotes, enabling environmental awareness, the detection of fine textures, and the manipulation of tools and objects during exploration and foraging. Corpuscles consist of a multilayered outer core enclosing a sensory inner core, which contains lamellar Schwann cells enveloping the afferent terminal at its center. In the traditional model, the outer core acts as a mechanical filter, enabling only high-frequency vibrations to reach the afferent terminal. Here, we show that the afferent terminal, not the outer core, carries out both the frequency filtering and sensory functions. We demonstrate that the detection of high-frequency vibration results from the afferent terminal’s sensitivity to stimulus velocity rather than to stimulus cycle rate. Furthermore, these properties are generally independent of the corpuscular environment and instead reflect the biophysical characteristics of the mechanically gated ion channels in the terminal, such as Piezo2. We present a revised model wherein the high-frequency tuning of Pacinian corpuscles is enabled by the velocity sensitivity of mechanotransduction in the afferent terminal. Pacinian corpuscles play a major role in tactile sensation by detecting vibrations. Here, authors show through direct electrophysiological recordings that Pacinian corpuscles detect vibrations via the sensitivity of the nerve terminal in the corpuscle’s inner core to stimulus velocity.
Chikamoto et al. (Tue,) studied this question.