A simulation environment for studying transcutaneous electrotactile stimulation

Gloria Araiza Illan,Ken E Friedl,Heiko Stüber,Ian R Summers,Angelika Peer

doi:10.1371/journal.pone.0212479

Abstract

Transcutaneous electrical nerve stimulation (TENS) allows the artificial excitation of nerve fibres by applying electric-current pulses through electrodes on the skin’s surface. This work involves the development of a simulation environment that can be used for studying transcutaneous electrotactile stimulation and its dependence on electrode layout and excitation patterns. Using an eight-electrode array implementation, it is shown how nerves located at different depths and with different orientations respond to specific injected currents, allowing the replication of already reported experimental findings and the creation of new hypotheses about the tactile sensations associated with certain stimulation patterns. The simulation consists of a finite element model of a human finger used to calculate the distribution of the electric potential in the finger tissues neglecting capacitive effects, and a cable model to calculate the excitation/inhibition of action potentials in each nerve.

Highlights

Mechanoreceptors transform mechanical stimuli into electrical signals
If the membrane potential rises above the excitation threshold, an action potential (AP) is induced, which will lead to the transmission of the signal towards the Central Nervous System (CNS)
For both setups we show the effects evaluated at two stages, as proposed by McNeal [7]: 1. The mapping of the currents Iel applied through the electrode array to the extracellular voltage Ve,n, evaluating the finite element model (FEM)

Summary

Introduction

Mechanoreceptors transform mechanical stimuli into electrical signals. Tactile sensations (texture, pressure, vibration, etc.) result from the excitation of cutaneous somatosensory receptors, such as Merkel cells, Meissner, Pacinian and Ruffini corpuscles. All interactions with objects involve the excitation of a large number of sensory units [2, 3]. The mechanical stimulus produces a change in the electric membrane potential of both the receptor and the nerve fibre connected to it. If the membrane potential rises above the excitation threshold, an action potential (AP) is induced, which will lead to the transmission of the signal towards the Central Nervous System (CNS). In: Sensory Mechanisms of the Spinal Cord: Volume 1 Primary Afferent Neurons and the Spinal Dorsal Horn. 2. The Psychophysics of Tactile Perception and Its Peripheral Physiological Basis.

Methods

Results

Discussion

Conclusion