Thermal block of action potentials is primarily due to voltage-dependent potassium currents: a modeling study
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Date
2019-06
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Neural Engineering
Abstract
Objective. Thermal block of action potential conduction using infrared lasers is a new modality for manipulating neural activity. It could be used for analysis of the nervous system and for therapeutic applications. We sought to understand the mechanisms of thermal block. Approach. To analyze the mechanisms of thermal block, we studied both the original Hodgkin/Huxley model, and a version modified to more accurately match experimental data on thermal responses in the squid giant axon. Main results. Both the original and modified models suggested that thermal block, especially at higher temperatures, is primarily due to a depolarization-activated hyperpolarization as increased temperature leads to faster activation of voltage-gated potassium ion channels. The minimum length needed to block an axon scaled with the square root of the axon's diameter. Significance. The results suggest that voltage-dependent potassium ion channels play a major role in thermal block, and that relatively short lengths of axon could be thermally manipulated to selectively block fine, unmyelinated axons, such as C fibers, that carry pain and other sensory information.
Description
Keywords
thermal block, infrared neural inhibition, computational model, unmyelinated axons, voltage-gated potassium channels, squid giant axon, scaling
Citation
Mohit Ganguly et al 2019 J. Neural Eng. 16 036020