Frequency shapes the quality of tactile percepts evoked through electrical stimulation of the nerves [article]

Emily L Graczyk, Breanne P Christie, Qinpu He, Dustin J Tyler, Sliman J Bensmaia
2020 bioRxiv   pre-print
The quality of tactile percepts evoked by skin vibrations depends on the frequency of stimulation: as frequency increases, the vibrotactile pitch increases. In the present study, we assessed the degree to which the quality of tactile percepts evoked via electrical stimulation of the somatosensory nerves is shaped by the frequency of the pulse train (PF). Participants with chronically-implanted peripheral nerve interfaces rated the quality of electrical pulse trains that varied in both PF and
more » ... se width (PW) along a single continuum and also described the subjective quality of the sensory experience using perceptual descriptors. We found that increases in PF led to systematic increases in perceived frequency independent of PW, up to about 50 Hz, at which point perceived frequency leveled off or decreased. PF discrimination matched its vibrotactile counterpart, yielding a Weber fraction of ~0.2 at low frequencies, but discrimination performance was abolished above 50 Hz. Finally, we found that PF systematically shaped quality as characterized by verbal descriptors at low but not high frequencies. Furthermore, even when probed in this complex, multi-dimensional space defined by descriptors, PF modulated tactile quality along a single perceptual continuum. In conclusion, we show that quality can be shaped by imposing temporal patterns on a fixed neural population, highlighting the importance of spike timing in the peripheral nerve. However, this temporal patterning can only be resolved up to about 50 Hz when stimulation is applied to populations of tactile nerve fibers.
doi:10.1101/2020.08.24.263822 fatcat:762mig5dazddtaqupynoo4myma