# Fascicle-selective kilohertz-frequency neural conduction block with longitudinal intrafascicular electrodes

## TL;DR

This study shows that high-frequency electrical stimulation using special electrodes can selectively block nerve signals in specific nerve bundles, offering a new way to treat abnormal neural activity.

## Contribution

The study introduces a method to achieve interfascicular selectivity and control in high-frequency neural conduction block using longitudinal intrafascicular electrodes.

## Key findings

- kHz stimulation with LIFEs can selectively block neural conduction in specific nerve fascicles.
- The degree of block can be adjusted by changing the amplitude and frequency of stimulation.
- Increasing the stimulation frequency reduces onset response spillover and allows muscle recovery from fatigue.

## Abstract

Objective. Electrical stimulation of peripheral nerves is used to treat a variety of disorders and conditions. While conventional biphasic pulse stimulation typically induces neural activity in fibers, kilohertz (kHz) continuous stimulation can block neural conduction, offering a promising alternative to drug-based therapies for alleviating abnormal neural activity. This study explores strategies to enhance the selectivity and control of high-frequency neural conduction block using intrafascicular electrodes. Approach. In vivo experiments were conducted in a rodent model to assess the effects of kHz stimulation delivered via longitudinal intrafascicular electrodes (LIFEs) on motor axons within the tibial and common peroneal fascicles of the sciatic nerve. Main results. We demonstrated that a progressive and selective block of neural conduction is achievable with LIFEs. We showed that the amount of neural conduction block can be tuned by adjusting the amplitude and frequency of kHz stimulation. Additionally, we achieved interfascicular selectivity with intrafascicular electrodes, with this selectivity being modulated by the kHz stimulation frequency. We also observed a small amount of onset response spillover, which could be minimized by increasing the blocking stimulus frequency. Muscle fatigue was quantified during kHz continuous stimulation and compared to control scenarios, revealing that the muscle was able to recover from fatigue during the block, confirming a true block of motor neurons. Significance. Our findings show that kHz stimulation using LIFEs can be precisely controlled to achieve selective conduction block. By leveraging existing knowledge from conventional stimulation techniques, this approach allows for the development of stimulation protocols that effectively block abnormal neural patterns with reduced side effects.