Journal: Scientific Reports
Article Title: New method for neuromodulation against pain using minimally invasive electrodes outside the epidural space
doi: 10.1038/s41598-025-07750-8
Figure Lengend Snippet: Results of in-vitro measurements of the Electric Field Vector at five different positions within the spinal canal inside a cross-sectional transverse XY plane cutting through vertebra T2. The electronic equipment equals that of the in-vitro setup depicted in Fig. , but this time without the components rendered in red in Fig. b, i.e. without the red dotted lines and the capacitor and voltage meter depicted in Fig. b. ( a ) Electric field probe consisting of 6 tiny point-shaped electrodes distributed on both sides of a thin insulating piece of circuit board, enabling the measurement of voltage differences in all of the three directions (X, Y, Z). This small field probe was mounted on a thin plastic rod and positioned at each of the five positions inside the spinal canal, as indicated by the five dots in ( b ). ( c ) Results of the E-field measurements using the probe depicted in ( a ), for each of the five positions within the cross-sectional plane. The five E-field vectors are rendered in red, whereas the grey structure indicating the spinal canal is a section of the inner surface of the bone structure (i.e., vertebra T2) rendered in ( b ). The strengths of the E-field (i.e. the length of the E-vectors depicted in ( c ), ( d ), and ( e )) are all expressed as a percentage of the strongest E-field measured, which is the E-field measured at point number 1 in ( c ). In ( c ), the resulting five E-vectors are rendered in full 3D. For clarity, however, we have also added a graphic that renders only the (X,Y)-components of each E-vector ( in ( d )), as well as a graphic rendering only the Z-component of each E-vector (in ( e )). In ( c ), ( d ), and ( e ), all numbers along the coordinate axes are in mm. Images were created by authors using Wolfram Mathematica 13.3 software ( www.wolfram.com/mathematica ).
Article Snippet: The simulation was performed on the commercial software Wolfram Mathematica (Wolfram Research, Inc., Mathematica, Version 12.1, Champaign, IL (2020)).
Techniques: In Vitro, Plasmid Preparation, Software
![Schematic of the essentials of multi-electrode local field annihilation. Notably, the local field in proximity of only one single clip is illustrated here, whereas both clips are required to 'close the circuit,' as demonstrated in Fig. . ( a ) The primary electrode Sp on the lower side of the clip administers a current towards the target of the stimulation, i.e. the dorsal columns in the white matter marked in yellow (label A). Meanwhile, the secondary electrode Ss placed on the upper side generates a weaker current of opposite phase, aimed at annihilating the stimulation of the (red) muscles in the back (marked with X). The color red of the electrodes in the picture indicates a positive phase of the output current, the blue one a negative phase. ( b ) Schematic representation of the “local quenching field” designed to prevent undesired muscle stimulation in the back. The generation of a main strong field by the primary electrode Sp close to the spinal cord, in combination with the opposite, counteracting, weaker field from the secondary electrode Ss in proximity to the muscle tissue, results in a “local quenching effect”. This effect ensures a predominant stimulating field in the red/purple/blue regions, where the intensity is such as to enable the fibers stimulation, while maintaining the field intensity below the fibers stimulation threshold in the light blue/yellow/green regions. Consequently, the target A region is readily stimulated while in the X region the stimulation is nearly absent. c ) Sketch of the “On/off function” called EnvelopeOfPulses(t)”, as described in Eqs. and , which describes the envelope of the current pulses administered during the spinal cord stimulation, consisting of a number of current pulses of duration \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau$$\end{document} and inter-pulse interval T. Images were created by authors using Wolfram Mathematica 13.3 software ( www.wolfram.com/mathematica ).](https://pub-med-central-images-cdn.bioz.com/pub_med_central_ids_ending_with_4473/pmc12274473/pmc12274473__41598_2025_7750_Fig2_HTML.jpg)
