Common computational principle for vibro-tactile pitch perception in mouse and human

We live surrounded by vibrations generated by moving objects. These oscillatory stimuli can produce sound (i.e. airborne waves) and propagate through solid substrates. Pitch is the main perceptual characteristic of sound, and a similar perceptual attribute seems to exist in the case of substrate vibrations: vibro-tactile pitch. Here, we establish a mechanistic relationship between vibro-tactile pitch perception and the actual physical properties of vibrations using behavioral tasks, in which vibratory stimuli were delivered to the human fingertip or the mouse forelimb. The resulting perceptual reports were analyzed with a model demonstrating that physically different combinations of vibration frequencies and amplitudes can produce equal pitch perception. We found that the perceptually indistinguishable but physically different stimuli follow a common computational principle in mouse and human. It dictates that vibro-tactile pitch perception is shifted with increases in amplitude toward the frequency of highest vibrotactile sensitivity. These findings suggest the existence of a fundamental relationship between the seemingly unrelated concepts of spectral sensitivity and pitch perception.