Model study of combined electrical and near-infrared neural stimulation on the bullfrog sciatic nerve

You, Mengxian; Mou, Zongxia

doi:10.1007/s10103-017-2222-x

Cited by 10 publications

(6 citation statements)

References 33 publications

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“…The experimental and theoretical findings of this present work demonstrate that electric and magnetic stimulation of the brain must take into account small thermal effects that are ubiquitously present during application of stimulation. More sophisticated models [82,83] of electrical current interaction with neurons combined with thermal effects will lead to a better understanding of the effects of stimulation on neuronal response and allow more precise control of neuronal circuitry.…”

Section: Discussionmentioning

confidence: 99%

Thermal effects on neurons during stimulation of the brain

et al. 2022

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All electric and magnetic stimulation of the brain deposits thermal energy in the brain. This occurs through either Joule heating of the conductors carrying current through electrodes and magnetic coils, or through dissipation of energy in the conductive brain. Objective. Although electrical interaction with brain tissue is inseparable from thermal effects when electrodes are used, magnetic induction enables us to separate Joule heating from induction effects by contrasting AC and DC driving of magnetic coils using the same energy deposition within the conductors. Since mammalian cortical neurons have no known sensitivity to static magnetic fi elds, and if there is no evidence of effect on spike timing to oscillating magnetic fields, we can presume that the induced electrical currents within the brain are below the molecular shot noise where any interaction with tissue is purely thermal. Approach. In this study, we examined a range of frequencies produced from micromagnetic coils operating below the molecular shot noise threshold for electrical interaction with single neurons. Main results. We found that small temperature increases and decreases of 1C caused consistent transient suppression and excitation of neurons during temperature change. Numerical modeling of the biophysics demonstrated that the Na-K pump, and to a lesser extent the Nernst potential, could account for these transient effects. Such effects are dependent upon compartmental ion fluxes and the rate of temperature change. Significance. A new bifurcation is described in the model dynamics that accounts for the transient suppression and excitation; in addition, we note the remarkable similarity of this bifurcation's rate dependency with other thermal rate-dependent tipping points in planetary warming dynamics. These experimental and theoretical findings demonstrate that stimulation of the brain must take into account small thermal effects that are ubiquitously present in electrical and magnetic stimulation. More sophisticated models of electrical current interaction with neurons combined with thermal effects will lead to more accurate modulation of neuronal activity.

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Section: Discussionmentioning

confidence: 99%

Thermal effects on neurons during stimulation of the brain

et al. 2022

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“…INM was first developed as IR neural stimulation to evoke the activity of neurons as reported by Wells et al . Later, both simulation and experimental studies reported that IR radiant exposure beyond a certain temperature threshold could be used to inhibit action potential generation and propagation, which is called infrared neural inhibition (INI). Although the exact mechanisms of INI are not yet fully understood, previous studies have concluded that it is based primarily on a photothermal mechanism .…”

Section: Introductionmentioning

confidence: 99%

Inhibition of cortical neural networks using infrared laser

Xia

Nyberg

2019

Journal of Biophotonics

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The aim of the present study is to optimize parameters for inhibiting neuronal activity safely and investigating thermal inhibition of rat cortex neural networks in vitro by continuous infrared (IR) laser. Rat cortex neurons were cultured on multi‐electrode arrays until neural networks were formed with spontaneous neural activity. Neurons were then irradiated to inhibit the activity of the networks using different powers of 1550 nm IR laser light. A finite element heating model, calibrated by the open glass pipette method, was used to calculate temperature increases at different laser irradiation intensities. A damage signal ratio (DSR) was evaluated to avoid excessive heating that may damage cells. The DSR predicted that cortex neurons should be safe at temperatures up to 49.6°C for 30 seconds, but experiments suggested that cortex neurons should not be exposed to temperatures over 46°C for 30 seconds. Neural response experiments showed that the inhibition of neural activity is temperature dependent. The normal neural activity could be inhibited safely with an inhibition degree up to 80% and induced epileptiform activity could be suppressed. These results show that continuous IR laser radiations provide a possible way to safely inhibit the neural network activity.

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“…Recently, INS has been applied for the stimulation of the retina nerves and the activation of the peripheral axon. 12,17 This method provides fine spatial resolution improving the selectivity of neural stimulations. In this study, we used a photothermal mechanism to estimate the spatial resolution of INS as a function of laser properties.…”

Section: Resultsmentioning

confidence: 99%

Blind Localization of Heating in Neural Tissues Induced by a Train of the Infrared Pulse Laser

Ansari

Zakeri

2019

J Lasers Med Sci

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Introduction: Recently, infrared lasers (wavelengths larger than 1100 nm) have been applied to stimulate neural tissues. Infrared neural stimulation (INS) has some advantages over conventional electric stimulation, including contact-free delivery, spatial precision, and lack of stimulation artifacts. In this study and based on a photothermal mechanism, we applied the heat diffusion equation to study temperature variation of a biological phantom during INS. In addition, the impact of laser parameters on spatially localized heating induced by 2 different infrared wavelengths were studied. Methods: We studied the localization of INS inside a phantom similar to cortical neural tissue. First, we analytically solved the heat diffusion equation to study the distribution of temperature inside this phantom. Then, the accuracy of analytical results was verified by heating the phantom using amplitude-modulated infrared lasers (lambda= 1450 and 1500 nm, the energy between 2 and 5 mJ and pulse duration up to 20 ms). The laser light was directed to sample by a multimode optical fiber (NA=0.22, core size= 200 microns). Finally, the impacts of laser properties on the spatial resolution of infrared heating were discerned. Results: In order to verify analytical results, we measured the maximum temperatures of the phantom during illumination of lasers and compared them with analytical results. The analytical results were in agreement with the experimental results. The effects of laser beam properties such as pulse duration, energy and repetition rate frequency on the spatial resolution were investigated. The results indicated that the spatial resolution of INS can be smaller than one millimeter. Conclusion: Here, the influences of laser properties on the localization of INS inside a biological phantom were studied. These results can be applied to improve the spatial selectivity of the peripheral nerve interface.

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Model study of combined electrical and near-infrared neural stimulation on the bullfrog sciatic nerve

Cited by 10 publications

References 33 publications

Thermal effects on neurons during stimulation of the brain

Thermal effects on neurons during stimulation of the brain

Inhibition of cortical neural networks using infrared laser

Blind Localization of Heating in Neural Tissues Induced by a Train of the Infrared Pulse Laser

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