Selective stimulation of bullfrog sciatic nerve by gold nanorod assisted combined electrical and near-infrared stimulation

You, Mengxian; Zhou, Rui; Mou, Zongxia

doi:10.1007/s10544-019-0428-3

Cited by 5 publications

(2 citation statements)

References 34 publications

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“…Because thermal effects will always accompany electric or magnetic stimulation, it is important to consider the combined effects. There have been a few experimental studies explicitly combining thermal and electrical stimulation of neurons demonstrating effects on stimulation thresholds and spatial selectivity [77][78][79][80][81].…”

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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“…(a) In-vivo experiments in: humans [60], rats [36, 43, 44, 48-50, 53, 55], gerbils [40, 41, 45-47, 52, 54] and quails [76]. (b) Ex-vivo experiments in: rats [77], lobsters [37], aplysia [55], rabbits [78], bullfrog [79] and murine [80]. (c) In-vitro experiments in: hippocampal and cortical neurons from rat [81,82], untransfected HEK-293 T cells, X. laevis oocytes and artificial lipid bilayers [67].…”

Section: Introductionmentioning

confidence: 99%

Infrared neurostimulation in ex-vivo rat sciatic nerve using 1470 nm wavelength

Cury¹,

Perre²,

Smets³

et al. 2021

J. Neural Eng.

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Objective. To design and implement a setup for ex-vivo optical stimulation for exploring the effect of several key parameters (optical power and pulse duration), activation features (threshold, spatial selectivity) and recovery characteristics (repeated stimuli) in peripheral nerves. Approach. A nerve chamber allowing ex-vivo electrical and optical stimulation was designed and built. A 1470 nm light source was chosen to stimulate the nerve. A photodiode module was implemented for synchronization of the electrical and optical channels. Main results. Compound neural action potentials (CNAPs) were successfully generated with infrared light pulses of 200–2000 µs duration and power in the range of 3–10 W. These parameters determine a radiant exposure for stimulation in the range 1.59–4.78 J cm−2. Recruitment curves were obtained by increasing durations at a constant power level. Neural activation threshold is reached at a mean radiant exposure of 3.16 ± 0.68 J cm−2 and mean pulse energy of 3.79 ± 0.72 mJ. Repetition rates of 2–10 Hz have been explored. In eight out of ten sciatic nerves (SNs), repeated light stimuli induced a sensitization effect in that the CNAP amplitude progressively grows, representing an increasing number of recruited fibres. In two out of ten SNs, CNAPs were composed of a succession of peaks corresponding to different conduction velocities. Significance. The reported sensitization effect could shed light on the mechanism underlying infrared neurostimulation. Our results suggest that, in sharp contrast with electrical stimuli, optical pulses could recruit slow fibres early on. This more physiological order of recruitment opens the perspective for specific neuromodulation of fibre population who remained poorly accessible until now. Short high-power light pulses at wavelengths below 1.5 µm offer interesting perspectives for neurostimulation.

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