A method and system for precise and tunable multi-target magnetic stimulation based on temporal coherence

Abstract

This invention relates to the field of magnetic stimulation technology, providing a time-coherent, multi-target, precisely adjustable magnetic stimulation method and system. The method includes constructing a coil array at the desired magnetic stimulation site. The coil array includes a first coil positioned at the center of the array and multiple second coils positioned around the periphery of the first coil. The first coil and the desired second coils are then energized. The frequency of the high-frequency alternating current supplied to the first coil and the energized second coils is controlled to generate a low-frequency envelope induced electric field between the first and second coils. The current amplitude ratio of the coil pair consisting of the first coil and one of the energized second coils is adjusted to adjust the focusing area of ​​the low-frequency envelope induced electric field, precisely locating and stimulating the desired target point. This invention improves stimulation depth and focus, and enables simultaneous stimulation of multiple targets, achieving adjustable, controllable, and precisely positioned stimulation without moving the coil positions.

Description

Technical Field

[0001] This invention relates to the field of magnetic stimulation technology, and in particular to a method and system for precise and adjustable multi-target magnetic stimulation based on time coherence. Background Technology

[0002] Currently, ischemic brain diseases caused by the nervous system and growth and development problems in children are increasingly appearing in society. These diseases are generally treated with neuromodulation.

[0003] Transcranial magnetic stimulation (TMS) utilizes the principle of electromagnetic induction. Under the influence of an applied alternating magnetic field, it generates an alternating induced electric field in the brain, causing biocurrents to be conducted in tissues. This depolarizes nerve fibers, neurons, and muscles, thereby affecting brain metabolism and neural electrical activity. TMS has gained favor among researchers and clinicians due to its non-invasiveness, safety, and minimal side effects, and has achieved preliminary results in the diagnosis of neurological function and the treatment of some neurological diseases. Temporal coherent magnetic stimulation (TMS) is a novel non-invasive deep brain neuromodulation technique. It introduces high-frequency alternating currents with small frequency differences into multiple coils, superimposing a low-frequency envelope induced electric field at the intracranial stimulation target. Due to the low-pass characteristics of neuronal membranes, areas without an envelope only contain high-frequency components, and neurons do not respond. This allows for stimulation of local neurons in deep brain regions without activating superficial neurons.

[0004] However, the stimulation effect of TMS is limited by the trade-off between target focusing and the depth of the induced electric field. For example, larger coils can achieve a deeper intracranial penetration distance and provide a stronger induced electric field, but the stimulation area is larger, while smaller coils can provide a narrower stimulation area but the stimulation depth is insufficient. The time-coherent stimulation targets are also relatively singular, making it difficult to achieve multi-brain region synergistic stimulation, which limits its application in the modulation of multiple nodes in the brain network. In addition, changing the stimulation area requires manually moving the coil, which is time-consuming and laborious. Summary of the Invention

[0005] To address these issues, the present invention provides a multi-target precise adjustable magnetic stimulation method and system based on time coherence, which solves the problems of poor stimulation effect caused by the imbalance between stimulation intensity and focusing in existing magnetic stimulation technologies, difficulty in achieving simultaneous stimulation of multiple targets, and cumbersome operation requiring manual movement of coils when changing stimulation targets.

[0006] This invention provides a method for precise and tunable magnetic stimulation of multiple targets based on temporal coherence, comprising the following steps:

[0007] S101: Construct a coil array at the desired magnetic stimulation site, the coil array including a first coil disposed at the center of the coil array and a plurality of second coils disposed around the periphery of the first coil;

[0008] S102: Turn on the first coil and the second coil that needs to be turned on;

[0009] S103: Control the frequency of the high-frequency alternating current supplied to the first coil and the conducting second coil to generate a low-frequency envelope induced electric field between the first coil and the second coil.

[0010] S104: Adjust the current amplitude ratio of the coil pair consisting of the first coil and one of the conducting second coils, so as to adjust the focusing area of ​​the low-frequency envelope induced electric field to accurately locate and stimulate the target point to be stimulated.

[0011] According to the present invention, in a time-coherent multi-target precise adjustable magnetic stimulation method, in step S102, the current transmission directions of the first coil and any of the conducting second coils are opposite, so as to generate an induced electric field focusing region between the first coil and any of the conducting second coils.

[0012] According to the present invention, a multi-target precisely tunable magnetic stimulation method based on time coherence is provided, wherein step S104, adjusting the current amplitude ratio to focus the low-frequency envelope induced electric field includes:

[0013] When the amplitude of the current flowing through the first coil is greater than the amplitude of the current in any of the second coils, the focusing region of the low-frequency envelope induced electric field shifts toward any of the second coils;

[0014] When the amplitude of the current flowing through the first coil is less than the amplitude of the current in any of the second coils, the focusing region of the low-frequency envelope induced electric field shifts toward the first coil;

[0015] When the amplitude of the current flowing through the first coil is equal to the amplitude of the current flowing through any of the second coils, the focusing region of the low-frequency envelope induced electric field does not shift.

[0016] According to the present invention, a multi-target precise adjustable magnetic stimulation method based on time coherence is provided, wherein in step S101, a plurality of second coils are uniformly arranged around the periphery of the first coil.

[0017] This invention also provides a time-coherent, multi-target, precisely tunable magnetic stimulation system, comprising:

[0018] Coil arrays are used to magnetically stimulate target points to be stimulated.

[0019] A control module is used to control whether the coil array is turned on and to control the AC frequency and current amplitude ratio of each coil in the coil array.

[0020] A power supply module is used to power the coil array and the control module.

[0021] According to the present invention, a multi-target precision adjustable magnetic stimulation system based on time coherence is provided, wherein the control module includes:

[0022] The host computer is used to receive control commands and send them to the digital signal processor;

[0023] A digital signal processor is used to process the received control commands and drive the IGBT modules in the power supply module to provide different AC frequencies and current amplitude ratios for the coil array.

[0024] This invention provides a time-coherent, multi-target, precisely adjustable magnetic stimulation method and system. By arranging a first coil and multiple second coils above the target point requiring magnetic stimulation, and then conducting high-frequency alternating current, a frequency difference is generated between the first coil and any second coil, producing a low-frequency envelope induced electric field. This utilizes the low-pass characteristics of the neuronal membrane to stimulate a deep and small region, improving stimulation depth and focus. Simultaneously, based on the coil array, multiple target points can be stimulated simultaneously. Furthermore, by controlling the current amplitude ratio in the coil group composed of the first coil and any second coil, an electric field strength difference is generated, which allows the relative positions of the coils to move. This enables adjustable, controllable, and precise positioning of the stimulation target point without manually moving the coil positions.

[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a multi-target precise adjustable magnetic stimulation method based on time coherence provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of a multi-target precision adjustable magnetic stimulation system based on time coherence provided in an embodiment of the present invention.

[0029] Figure label:

[0030] 1. First coil; 2. Second coil; 11. Host computer; 12. Digital signal processor; 100. Coil array; 200. Control module; 300. Power supply module. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but should not be used to limit the scope of this invention.

[0032] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0034] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0036] The following is combined with Figures 1 to 2 The embodiments provided by the present invention are described below.

[0037] This invention provides a multi-target precisely tunable magnetic stimulation method based on temporal coherence, comprising the following steps:

[0038] S101: Construct a coil array at the desired magnetic stimulation site;

[0039] Furthermore, the coil array includes a first coil disposed at the center of the coil array and a plurality of second coils, the plurality of second coils being disposed around the periphery of the first coil;

[0040] Furthermore, both the first coil and the second coil are arranged in a circle, with the center of the first coil coinciding with the center of the array, and both the first coil and the multiple second coils are made of copper, a metal with good electrical conductivity.

[0041] In some embodiments, a coil array is formed by seven circular coils, which are numbered respectively. The first coil 1 is the center coil, and the rest are second coils. These include a second coil located directly above the first coil 1, a second coil located to the upper right of the first coil 1, a second coil located to the lower right of the first coil 1, and a second coil located directly below the first coil 1.

[0042] In some embodiments, all coils are circular coils of the same size, with a coil wiring diameter of 2mm and 6 turns, such as... Figure 2 The arrangement shown is such that the center of the first coil 1 coincides with the center of the coil array, and the remaining second coils are arranged in clockwise order around the first coil in a circle with a radius of 25mm.

[0043] S102: Turn on the first coil and the second coil that needs to be turned on;

[0044] S103: Control the frequency of the high-frequency alternating current supplied to the first coil and the conducting second coil to generate a low-frequency envelope induced electric field between the first coil and the second coil.

[0045] In some embodiments, referring to the coil array described above, an induced electric field focusing region is generated at the intersection of the first coil 1 and the uppermost second coil only when reverse current is applied. Similarly, when the first coil 1 and the uppermost second coil, the lower right second coil, and the second coil 6 are conducting, three induced electric field focusing regions can be generated around the first coil 1, located at the intersection of the first coil 1 and the uppermost second coil, the intersection of the first coil 1 and the lower right second coil, and the intersection of the first coil 1 and the second coil 6, respectively.

[0046] In some embodiments, when a 1.05 kHz AC current is applied to the first coil 1 and a 1.00 kHz AC current is applied to the second coil directly above it, a low-frequency envelope induced electric field modulated to 50 Hz will be generated at the intersection of the first coil 1 and the second coil directly above it.

[0047] S104: Adjust the current amplitude ratio of the coil pair consisting of the first coil and one of the conducting second coils, so as to adjust the focusing area of ​​the low-frequency envelope induced electric field to accurately locate and stimulate the target point to be stimulated.

[0048] Furthermore, the current amplitude ratio that appears in step S104 is the ratio of the current of the first coil and the second coil in the coil pair. When there is a ratio difference in the current, the two coils will have a relative displacement due to the difference in the intensity of the induced electric field generated therein.

[0049] In step S102, the current transmission directions of the first coil and any of the conducting second coils are opposite, so as to generate an induced electric field focusing region between the first coil and any of the conducting second coils.

[0050] In step S104, adjusting the current amplitude ratio to focus the low-frequency envelope induced electric field includes:

[0051] When the amplitude of the current flowing through the first coil is greater than the amplitude of the current in any of the second coils, the focusing region of the low-frequency envelope induced electric field shifts toward any of the second coils;

[0052] When the amplitude of the current flowing through the first coil is less than the amplitude of the current in any of the second coils, the focusing region of the low-frequency envelope induced electric field shifts toward the first coil;

[0053] When the amplitude of the current flowing through the first coil is equal to the amplitude of the current flowing through any of the second coils, the focusing region of the low-frequency envelope induced electric field does not shift.

[0054] In step S101, multiple second coils are evenly distributed around the periphery of the first coil.

[0055] Furthermore, when the coils are evenly distributed, the focusing area of ​​the low-frequency envelope induced electric field becomes more regular, meaning it can be more easily controlled systematically. Relatively speaking, the focusing ability is also improved compared to traditional magnetic stimulation.

[0056] The following is combined with Figure 2 The present invention describes a time-coherent, multi-target, precisely tunable magnetic stimulation system, comprising:

[0057] Coil array 100 is used to magnetically stimulate the target point to be stimulated.

[0058] The control module 200 is used to control whether the coil array 100 is turned on, and to control the AC frequency and current amplitude ratio of each coil in the coil array 100.

[0059] The power module 300 is used to supply power to the coil array 100 and the control module 200.

[0060] The control module 200 includes:

[0061] The host computer 11 is used to receive control commands and send them to the digital signal processor 12;

[0062] The digital signal processor 12 is used to process the received control commands and drive the IGBT modules in the power supply module 300 to provide different AC frequencies and current amplitude ratios to the coil array 100.

[0063] Furthermore, the power module includes an IGBT module and a power supply, as well as a transformer, a rectifier module, and an energy storage capacitor.

[0064] In some embodiments, the staff sends control commands through a host computer. The host computer acts as a relay station for human-computer interaction and sends the control commands to a digital signal processor. The digital signal processor processes the received control commands and converts them into electrical signals to drive the IGBT module in the power supply module. When the IGBT receives the electrical signal, it converts the electrical signal into a control level to conduct the coil array, thereby performing magnetic stimulation on the target point to be magnetically stimulated.

[0065] In some embodiments, referring to the coil array described above, a first coil 1 is selected, and a differential frequency alternating current is passed through the upper and lower second coils. A simulation experiment is conducted in human tissue fluid to simulate the multi-target effect of a time-coherent multi-target precise adjustable magnetic stimulation method provided by the present invention.

[0066] In some embodiments, the simulation is performed using the COMSOL simulation platform, a multiphysics coupled finite element simulation software that includes modules for mechanics, electromagnetics, acoustics, and heat transfer. For the simulation of transcranial magnetic stimulation (TMS), the electromagnetic field module of COMSOL is selected for finite element analysis. The specific steps are as follows: First, a multi-target magnetic stimulation saline model is constructed to simulate the induced electric field distribution in human tissue fluid. A rectangular saline model with dimensions of 300×300×40mm is selected, and a coil array, as described above, is also included, located 5mm above the upper surface of the saline model. Material properties are assigned: the conductivity of the saline model is set to 0.333 S / m, and the relative permittivity is set to 100; the conductivity of the coil array is set to 5.998×10⁷ S / m, and the relative permittivity is set to 1. The induced electric field intensity is then solved using a transient analysis tool. Calculate the low-frequency envelope induced electric field intensity at any position n between the first coil 1 and the second coil directly above it, or between the first coil 1 and the second coil directly below it. and modulation intensity wait.

[0067] In some embodiments, an alternating current with an amplitude of 2000A is passed through the first coil 1, the upper second coil, and the lower second coil. The current frequency of the first coil 1 is set to 1.05KHz, and the current frequency of the upper and lower second coils is set to 1.00KHz. The purpose of the applied differential frequency is to modulate a low-frequency envelope induced electric field with a frequency of 50Hz in the focusing region between the first coil and any of the second coils.

[0068] In some embodiments, the lower surface of the coil array is selected as a plane parallel to the coil array, and a plane diagram of the induced electric field components is drawn. The center of the first coil 1 is defined as the origin of the coordinate system, and the line connecting the center of the first coil 1 and the center of the second coil directly above it is the Y-axis, with the positive direction pointing to the second coil directly above it. The X-axis is a straight line perpendicular to the Y-axis, with the positive direction pointing to the second coil to the upper right and the second coil to the lower right. In the plane diagram of the induced electric field components, two focusing areas appear, located between the first coil 1 and the second coil directly above it, and between the first coil 1 and the second coil directly below it, respectively, to meet the requirement of stimulating multiple target points simultaneously.

[0069] In some embodiments, the low-frequency envelope induced electric field modulation intensity at any quantized point is:

[0070]

[0071] here, This represents the modulation intensity of the low-frequency envelope induced electric field at any location n in space. This represents the magnitude of the induced electric field at any position n. This represents the magnitude of the induced electric field at position n; here, when Approaching equality, and When the sum of is greater, the modulation effect is better.

[0072] In some embodiments, referring to the simulation platform, rectangular saline model and coil array described above, differential frequency alternating current is passed through the first coil 1 and the second coil directly above it to simulate an experiment in human tissue fluid, in order to simulate the stimulation position fine-tuning of a time-coherent multi-target precise adjustable magnetic stimulation method provided by the present invention.

[0073] In some embodiments, the specific steps involve fixing the total current of the first coil 1 and the second coil directly above it to 4000A, and then adjusting the current ratio of the two coils to observe... The peak position change was analyzed to determine the relationship between the movement of the focusing area and the ratio of the current in the first coil 1 and the current in the second coil directly above it.

[0074] In some embodiments, a control group and an experimental group are set up for the experiment. Specifically, the current frequency of the first coil 1 is kept constant at 1.05KHz and the current frequency of the second coil directly above it is kept constant at 1.00KHz. The total current of the two coils is fixed at 4000A. The current ratio of the control group is set at 1:1, that is, both coils are supplied with AC current of 2000A. The current ratio of the experimental group is set at 1:3, that is, 1000A is supplied to the first coil 1 and 3000A is supplied to the second coil directly above it. Simulation analysis is then performed.

[0075] In some embodiments, the lower surface of the coil is selected as a plane parallel to the coil, and a planar diagram of the induced electric field components is plotted. First, the line connecting the centers of the first coil 1 and the other two coils is defined as the Y-axis, with the positive direction pointing directly upwards towards the second coil. Next, the midpoint of the line connecting the centers of the two coils is selected as the origin. Then, the X-axis is defined as a straight line passing through the origin and perpendicular to the Y-axis, with the positive direction pointing towards the upper right and lower right second coils. Ten points are selected on each side of the origin on the Y-axis (x=0), with a step size of 2mm, called array 1. Similarly, array 1 is moved 5mm along the positive X-axis to become array 2. Each array has two sets of data, called data 1 and data 2, where data 1 represents the experimental group (1:3) and data 2 represents the control group (1:3). The two sets of data from array 1 and array 2 are plotted in two separate graphs for analysis.

[0076] In some embodiments, experimental results show that the dot-line graphs of data 1 and data 2 are symmetrical, and the induced electric field The peaks are located at their respective centers of symmetry and gradually decrease from left to right; however, the two data points... The peak values ​​did not overlap, and the spacing was 8 mm (the peak value was located at the origin in the 1:1 case, while it was located at coordinate (-8) in the 1:3 case). The results indicate that changing the current ratio affects... The peak position, i.e. the focusing area, changes with the magnitude of the current amplitude ratio in the coil pair, and the peak position shifts toward the side with the smaller current.

[0077] This invention provides a multi-target precise adjustable magnetic stimulation method and system based on temporal coherence. By controlling the conduction of different coil pairs, multiple sets of coils can be driven simultaneously to achieve simultaneous stimulation of multiple targets. Based on temporal coherence and the low-pass characteristics of neuronal membranes, both stimulation intensity and focusing intensity can be improved, resulting in deep and small stimulation of the target points. This stimulates deep brain regions without activating neurons in superficial tissues such as the scalp or muscles. Furthermore, by controlling the current amplitude ratio of the conducting coil pairs, the stimulation position can be finely adjusted, achieving displacement and precise positioning of the stimulation target points without manually moving the coils.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-target, precisely tunable magnetic stimulation method based on temporal coherence, characterized in that, Includes the following steps: S101: Construct a coil array at the desired magnetic stimulation site, the coil array including a first coil disposed at the center of the coil array and a plurality of second coils disposed around the periphery of the first coil; S102: Turn on the first coil and the second coil that needs to be turned on; S103: Control the frequency of the high-frequency alternating current supplied to the first coil and the conducting second coil to generate a low-frequency envelope induced electric field between the first coil and the second coil. S104: Adjust the current amplitude ratio of the coil pair consisting of the first coil and one of the conducting second coils, so as to adjust the focusing area of ​​the low-frequency envelope induced electric field to accurately locate and stimulate the target point to be stimulated. The current amplitude ratio adjustment for the focusing region of the low-frequency envelope induced electric field includes: When the amplitude of the current flowing through the first coil is greater than the amplitude of the current in any of the second coils, the focusing region of the low-frequency envelope induced electric field shifts toward any of the second coils; When the amplitude of the current flowing through the first coil is less than the amplitude of the current in any of the second coils, the focusing region of the low-frequency envelope induced electric field shifts toward the first coil; When the amplitude of the current flowing through the first coil is equal to the amplitude of the current flowing through any of the second coils, the focusing region of the low-frequency envelope induced electric field does not shift.

2. The method for precise and tunable multi-target magnetic stimulation based on temporal coherence according to claim 1, characterized in that, In step S102, the current transmission direction of the first coil and any of the conducting second coils is opposite, so as to generate an induced electric field focusing region between the first coil and any of the conducting second coils.

3. The method for precise and tunable multi-target magnetic stimulation based on temporal coherence according to claim 1, characterized in that, In step S101, multiple second coils are evenly distributed around the periphery of the first coil.

4. A time-coherent multi-target precisely tunable magnetic stimulation system for performing the time-coherent multi-target precisely tunable magnetic stimulation method as described in any one of claims 1 to 3, characterized in that, include: Coil arrays are used to magnetically stimulate target points to be stimulated. A control module is used to control whether the coil array is turned on and to control the AC frequency and current amplitude ratio of each coil in the coil array. A power supply module is used to power the coil array and the control module.

5. The multi-target precise adjustable magnetic stimulation system based on time coherence according to claim 4, characterized in that, The control module includes: The host computer is used to receive control commands and send them to the digital signal processor; A digital signal processor is used to process the received control commands and drive the IGBT modules in the power supply module to provide different AC frequencies and current amplitude ratios for the coil array.

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