Pre-neuronal processing of haptic sensory cues via dispersive high-frequency vibrational modes

Abstract

AbstractSense of touch is one of the major channels of perception. Neural coding of object features conveyed by rodents’ whiskers has been a model to study early stages of haptic information uptake. While high-precision spike timing has been observed during whisker sweeping across textured surfaces, the exact nature of whisker micromotions that spike trains encode remained elusive. Here, we discovered that whisker swept over textured object vibrates with a regular series of higher order vibrational modes spanning frequencies up to 10KHz. These high frequency modes carry up to 80% of vibrational energy, exhibit 100X smaller damping ratio, and propagate along the whisker 10X faster, that makes them the fastest and the most powerful messengers of shockwaves generated by micro-collisions with surface roughness. We conclude that a whisker is a dispersive pre-neuronal processor that transforms tactile information into a time sequenced code with ultra-high information capacity that contributes to haptic perception.