Nanosecond Pulse Bursts for Neuron Stimulation

Abstract

Nanosecond pulsed electrical field (nsPEF) is a novel approach for neuron stimulation however, applicability is limited due to the required relatively high electric field that could result in neuron damage. We reached the stimulation threshold using lower pulse amplitudes by applying a burst of multiple pulses (up to 4 MHz). Action potential (AP) in rat neurons in vitro was registered using a fluorescent probe, FluoVolt. We determined neuron excitation thresholds modulating burst parameters: number of pulses (1-1000), repetition rates (1 Hz-4 MHz) and duration (100 ns, 400 ns, 800 ns). Time-average electrical field values were used to compare nsPEF bursts and single pulse protocols. nsPEF burst exhibits lower time-average electrical field thresholds compared to single-pulse stimulations. Bursts of 100 ns pulses at 100 kHz for 100 µs caused neuron stimulation at 32.8 V/cm time-average electric field, where a single 100 µs pulse requires 165.7 V/cm, resulting in 80% reduction. Multiple stimulation and evaluation of corresponding AP trace shapes were used to identify neuron damage. µs pulses and nsPEF bursts at 250 kHz and above resulted in 100 stimulations without neuron damage. nsPEF bursts of lower pulse repetition rates required higher electrical field peak strengths, resulting in neuron damage visible as distorted AP trace or lack of excitation. Neuron stimulation can be achieved using nsPEF bursts that allow reducing electric field threshold without causing cellular damage