Temporal patterns in electrical nerve stimulation: Burst gap code shapes tactile frequency perception.

Kevin K W Ng,Christoffer Olausson,Richard M Vickery,Ingvars Birznieks,Gennady Cymbalyuk

doi:10.1371/journal.pone.0237440

Kevin K W Ng, Christoffer Olausson + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0237440

Copy DOI

Abstract

We have previously described a novel temporal encoding mechanism in the somatosensory system, where mechanical pulses grouped into periodic bursts create a perceived tactile frequency based on the duration of the silent gap between bursts, rather than the mean rate or the periodicity. This coding strategy may offer new opportunities for transmitting information to the brain using various sensory neural prostheses and haptic interfaces. However, it was not known whether the same coding mechanisms apply when using electrical stimulation, which recruits a different spectrum of afferents. Here, we demonstrate that the predictions of the burst gap coding model for frequency perception apply to burst stimuli delivered with electrical pulses, re-emphasising the importance of the temporal structure of spike patterns in neural processing and perception of tactile stimuli. Reciprocally, the electrical stimulation data confirm that the results observed with mechanical stimulation do indeed depend on neural processing mechanisms in the central nervous system, and are not due to skin mechanical factors and resulting patterns of afferent activation.

Highlights

Temporal features of neural spike activity play a major role in encoding tactile information [1,2,3,4]
Electrical stimulation with patterns used in Experiment 1 (Fig 1A) resulted in sensory nerve action potentials (SNAPs) that were consistent within a burst irrespective of inter-pulse intervals used or the number of pulses
To examine pulse-to-pulse variability within individual bursts, we normalised the amplitude of subsequent SNAPs to that of the first SNAP for each burst; this showed that the nerve response to pulses occurring later in a burst were not negatively affected by preceding pulses (Fig 3B), which suggests that the stimulus burst patterns were faithfully reproduced in the nerve firing patterns

Summary

Introduction

Temporal features of neural spike activity play a major role in encoding tactile information [1,2,3,4]. Electrical burst stimulation has been suggested to be useful in restoring the sense of touch in amputees using a prosthesis [10,11,12] or in the treatment of movement disorders through deep brain stimulation [13,14,15].

Objectives

Methods

Results

Discussion

Conclusion