Low frequency focused electric stimulation device and method

Abstract

The embodiment of the application discloses a low-frequency focused electric stimulation device and method, the device comprises: an ultrasonic wave emitting module, which is used for emitting three beams of ultrasonic waves to a target position, wherein the three beams of ultrasonic waves are perpendicular to each other, and are focused on a target position of a sample to be stimulated, the center frequencies of the three beams of ultrasonic waves form an arithmetic sequence, and the signal frequency difference of two beams of ultrasonic waves adjacent in frequency is equal to a preset interference frequency; a static magnetic field generating module, which is used for generating a constant static magnetic field at the target position, so that the constant static magnetic field and the three beams of ultrasonic waves generate a target low-frequency alternating current signal at the target position, wherein the magnetic field direction of the constant static magnetic field is perpendicular to the combined direction of the three beams of ultrasonic waves emitted by the ultrasonic wave emitting module. Through the technical scheme of the embodiment of the application, the effect of providing a spatially symmetric, high-resolution low-frequency induced electric field and current to induce neuron electrical activity is realized.

Description

Technical Field

[0001] The present invention relates to electrical stimulation technology, and more particularly to a low-frequency focused electrical stimulation device and method. Background Technology

[0002] Existing magnetoacoustic coupling stimulation devices mainly use a single ultrasonic transducer to inject high-frequency (MHz-level) ultrasound waves into the conductive tissue to be stimulated, while simultaneously applying a static magnetic field perpendicular to the direction of ultrasound propagation. Based on the magnetoacoustic coupling effect, a high-frequency (MHz-level) induced electric field and current with a frequency comparable to the ultrasound frequency will be generated here, which is suitable for studying the effects of high-frequency (MHz-level) electrical stimulation on neurons.

[0003] However, neurons exhibit low-pass filtering characteristics; therefore, existing magnetoacoustic coupling stimulation devices cannot generate low-frequency currents that more readily elicit neuronal responses. Furthermore, using a single ultrasonic transducer results in the ultrasonic beam having good focusing only in the direction perpendicular to propagation, with poor focusing in other directions. Summary of the Invention

[0004] This invention provides a low-frequency focused electrical stimulation device and method to achieve the effect of providing a spatially symmetrical, high-resolution low-frequency induced electric field and current to induce neuronal electrical activity.

[0005] In a first aspect, embodiments of the present invention provide a low-frequency focused electrical stimulation device, the device comprising:

[0006] An ultrasonic transmitting module is used to emit three ultrasonic beams toward a target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the signal frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency.

[0007] A static magnetic field generating module is used to generate a constant static magnetic field at a target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location, wherein the magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module.

[0008] Secondly, embodiments of the present invention also provide a low-frequency focused electrical stimulation method, the method comprising:

[0009] Based on the ultrasonic transmitting module, three ultrasonic beams are emitted toward the target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the signal frequency difference between two adjacent ultrasonic beams is equal to the preset interference frequency.

[0010] Based on the static magnetic field generating module, a constant static magnetic field is generated at the target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location. The magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module.

[0011] The technical solution of this invention uses an ultrasonic transmitting module to emit three ultrasonic beams toward a target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency. A static magnetic field generating module generates a constant static magnetic field at the target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location. The magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module. This solves the problems of excessively high electrical signal frequency and poor focusing when inducing neuronal electrical activity, and achieves the effect of providing a spatially symmetrical, high-resolution low-frequency induced electric field and current to induce neuronal electrical activity. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of exemplary embodiments of the present invention, the accompanying drawings used in describing the embodiments are briefly introduced below. Obviously, the accompanying drawings described are only a portion of the drawings of the embodiments to be described in this invention, and not all of the drawings. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0013] Figure 1 This is a schematic diagram illustrating the working principle of a low-frequency focused electrical stimulation device provided in Embodiment 1 of the present invention.

[0014] Figure 2 This is a schematic diagram illustrating the working principle of a low-frequency focused electrical stimulation device provided in Embodiment 2 of the present invention.

[0015] Figure 3 This is a schematic diagram illustrating the amplitude variation of the combined vibration of three ultrasonic beams according to Embodiment 2 of the present invention;

[0016] Figure 4 This is a schematic diagram illustrating the working principle of a low-frequency focused electrical stimulation device provided in Embodiment 3 of the present invention.

[0017] Figure 5 This is a schematic flowchart of a low-frequency focused electrical stimulation method provided in Embodiment 4 of the present invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0019] Example 1

[0020] Figure 1 This is a schematic diagram of the working principle of a low-frequency focused electrical stimulation device provided in Embodiment 1 of the present invention. This embodiment is applicable to situations where a low-frequency alternating current signal is generated at the target location to be stimulated. The device can be used to perform a low-frequency focused electrical stimulation method. The device can be implemented in the form of software and / or hardware. The hardware can be an electronic device, and optionally, the electronic device can be a mobile terminal, a PC, a server, etc.

[0021] like Figure 1 The low-frequency focused electrical stimulation device of this embodiment includes: an ultrasonic wave emitting module 1 and a static magnetic field generating module 2.

[0022] The ultrasonic transmitting module 1 is used to emit three ultrasonic beams toward the target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the frequency difference between two adjacent ultrasonic beams is equal to the preset interference frequency. The static magnetic field generating module 2 is used to generate a constant static magnetic field at the target location so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location. The magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module 1.

[0023] Ultrasonic transmitting module 1 is used to transmit three ultrasonic beams toward the target location.

[0024] In this configuration, three ultrasonic beams are perpendicularly aligned and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency. Optionally, the frequency difference between the highest and lowest frequency ultrasonic beams is twice the preset interference frequency. The sample to be stimulated can be a sample requiring low-frequency alternating current stimulation. The target location can be a stimulation target point within the sample. The preset interference frequency can be a pre-set signal frequency capable of generating simple harmonic interference phenomena. The value of the preset interference frequency should be much smaller than the signal frequency of any one of the ultrasonic beams; however, this is not specifically limited in this embodiment.

[0025] Specifically, the ultrasonic transmitting module 1 can emit three ultrasonic beams toward the target location. These three ultrasonic beams are focused on the target location, which can produce a simple harmonic interference phenomenon at the target location.

[0026] It should be noted that for three ultrasonic beams to produce simple harmonic interference, they must be perpendicular to each other in space and intersect at a single point, which is the target location. Furthermore, the frequencies of the three ultrasonic beams must be similar to produce simple harmonic interference.

[0027] The static magnetic field generating module 2 is used to generate a constant static magnetic field at the target location, so that the constant static magnetic field and three ultrasonic beams generate a target low-frequency AC signal at the target location.

[0028] The constant static magnetic field can be the magnetic field required to generate the magnetoacoustic coupling effect, and its direction is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module 1. The target low-frequency AC signal can be a low-frequency AC signal focused at the target location, i.e., an induced electric field and an induced current. The resultant direction of the three ultrasonic beams can be the direction of the combined ultrasonic signal generated by focusing the three ultrasonic beams at the target location.

[0029] Specifically, the static magnetic field generating module 2 can generate a stable static magnetic field at the target location, and the direction of the stable static magnetic field can be adjusted so that the magnetic field direction is perpendicular to the resultant direction of the three ultrasonic beams, so as to generate a magnetoacoustic coupling effect at the target location. Alternatively, the direction of the three ultrasonic beams generated by the ultrasonic wave transmitting module 1 can be adjusted so that the resultant direction of the three ultrasonic beams is perpendicular to the magnetic field direction.

[0030] It should be noted that the magnetoacoustic coupling effect refers to the interaction between ultrasonic waves and a constant static magnetic field in conductive tissue to couple an induced electric field and a current. Therefore, the ultrasonic waves emitted by the ultrasonic wave transmitting module 1, generated by the simple harmonic interference phenomenon, can couple a target low-frequency alternating current signal with the constant static magnetic field generated by the static magnetic field generating module 2.

[0031] The technical solution of this invention uses an ultrasonic transmitting module to emit three ultrasonic beams toward a target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency. A static magnetic field generating module generates a constant static magnetic field at the target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location. The magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module. This solves the problems of excessively high electrical signal frequency and poor focusing when inducing neuronal electrical activity, and achieves the effect of providing a spatially symmetrical, high-resolution low-frequency induced electric field and current to induce neuronal electrical activity.

[0032] Example 2

[0033] Figure 2This is a schematic diagram illustrating the working principle of a low-frequency focused electrical stimulation device provided in Embodiment 2 of the present invention.

[0034] like Figure 2 The ultrasonic transmitting module 1 in the low-frequency focused electrical stimulation device of this embodiment includes: a pulsed ultrasonic excitation source 11, a first ultrasonic transducer 12, a second ultrasonic transducer 13, and a third ultrasonic transducer 14.

[0035] The system includes a pulsed ultrasonic excitation source 11 for providing an ultrasonic excitation signal; a first ultrasonic transducer 12 connected to the pulsed ultrasonic excitation source 11 for converting the ultrasonic excitation signal corresponding to the first ultrasonic transducer 12 in the ultrasonic excitation source 11 into a first ultrasonic wave; a second ultrasonic transducer 13 connected to the pulsed ultrasonic excitation source 11 for converting the ultrasonic excitation signal corresponding to the second ultrasonic transducer 13 in the ultrasonic excitation source 11 into a second ultrasonic wave; and a third ultrasonic transducer 14 connected to the pulsed ultrasonic excitation source 11 for converting the ultrasonic excitation signal corresponding to the third ultrasonic transducer 14 in the ultrasonic excitation source 11 into a third ultrasonic wave; wherein the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave are perpendicular to each other.

[0036] The ultrasonic excitation signal can be an electrical signal used to generate an ultrasonic signal.

[0037] Specifically, the pulsed ultrasonic excitation source 11 provides at least three channels of ultrasonic excitation signals. These ultrasonic excitation signals have similar frequencies, and their amplitudes and phases can be the same or different. The ultrasonic excitation signals generated by the three channels in the pulsed ultrasonic excitation source 11 act on the first ultrasonic transducer 12, the second ultrasonic transducer 13, and the third ultrasonic transducer 14, respectively, so that the first ultrasonic transducer 12, the second ultrasonic transducer 13, and the third ultrasonic transducer 14 convert the corresponding ultrasonic excitation signals into corresponding ultrasonic waves, namely, the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave. In order to ensure that the three ultrasonic waves can meet the conditions for the generation of simple harmonic motion interference, the frequency difference between any two ultrasonic waves is made less than a preset interference frequency, and the direction of the ultrasonic waves is adjusted so that the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave are perpendicular to each other in space.

[0038] Optionally, the pulsed ultrasound excitation source 11 can be a three-channel pulsed ultrasound excitation source, and the first ultrasound transducer 12, the second ultrasound transducer 13 and the third ultrasound transducer 14 are all single-element focused ultrasound transducers.

[0039] like Figure 2 The low-frequency focused electrical stimulation device in this embodiment further includes: a fixing module 3.

[0040] The fixing module 3 is used to fix the first ultrasonic transducer 12, the second ultrasonic transducer 13 and the third ultrasonic transducer 14, and to adjust the position and angle of the first ultrasonic transducer 12, the second ultrasonic transducer 13 and the third ultrasonic transducer 14.

[0041] Specifically, the fixing module 3 can be a liftable and rotatable fixing device, on which the first ultrasonic transducer 12, the second ultrasonic transducer 13, and the third ultrasonic transducer 14 can be mounted for fixation. Furthermore, the position and angle of the first ultrasonic transducer 12, the second ultrasonic transducer 13, and the third ultrasonic transducer 14 can be adjusted by the position and angle of the fixing module 3, so that the three ultrasonic beams are perpendicular to each other in space.

[0042] Optionally, the fixed module 3 includes three non-ferromagnetic universal cantilever brackets.

[0043] The first, second, and third ultrasonic transducers are fixed on a non-ferromagnetic universal cantilever bracket, the height and angle of which are adjustable.

[0044] Specifically, in the non-ferromagnetic universal cantilever bracket, the reason for non-ferromagnetism is to avoid the magnetic field generated by the fixed module 3 from affecting the target low-frequency AC signal generated at the target position. The universal cantilever bracket means that it can be fixed and moved in various directions to achieve the function of height and angle adjustment.

[0045] Based on the above embodiments, in order for the three ultrasonic beams to produce a simple harmonic interference phenomenon, the center frequencies of the three ultrasonic beams must satisfy the following condition:

[0046] Δf = f1 - f2 = f2 - f3 << f3 <f2<f1

[0047] Where f1 is the highest frequency among the center frequencies of the three ultrasonic beams, f2 is the middle frequency among the center frequencies of the three ultrasonic beams, f3 is the lowest frequency among the center frequencies of the three ultrasonic beams, and Δf is the preset interference frequency, which is the difference between the highest frequency and the middle frequency, and also the difference between the middle frequency and the lowest frequency.

[0048] Specifically, by adjusting the excitation parameters of the pulsed ultrasonic excitation source 11, the difference in center frequencies of the ultrasonic beams emitted by the three focused ultrasonic transducers can be made much smaller than the center frequency of each ultrasonic beam, and the difference in center frequencies of two ultrasonic beams with similar frequencies can be equal.

[0049] For example, f1 = 500.0 kHz, f2 = 502.5 kHz, and f3 = 505.0 kHz. The schematic diagram of the amplitude change of the combined vibration of the three ultrasonic beams is shown below. Figure 3 As shown. According to Figure 3 It can be seen that the combined vibration of the three ultrasonic beams consists of a wave with a higher amplitude followed by a wave with a lower amplitude. If we consider the large wave and the small wave as one period, then the period of the combined vibration is T = 0.004s, and the frequency is... The period of amplitude change of the combined ultrasonic beam is the difference between the frequencies of two adjacent ultrasonic beams. Therefore, the frequency of the combined ultrasonic beam is much smaller than the center frequency of any one of the three ultrasonic beams.

[0050] Based on the above embodiments, the static magnetic field generating module 2 includes at least two sets of permanent magnets.

[0051] Each set of permanent magnets includes two permanent magnets of the same size and with matching magnetic induction intensity. The N pole of the first permanent magnet and the S pole of the second permanent magnet in each set are placed opposite each other.

[0052] Specifically, a steady static magnetic field can be generated using permanent magnet arrays. Each array includes a first permanent magnet and a second permanent magnet, with the N pole of the first permanent magnet and the S pole of the second permanent magnet placed opposite each other to produce a steady static magnetic field. Furthermore, the first and second permanent magnets are of the same size and have comparable magnetic induction intensities. To adjust the magnetic field strength of the steady static magnetic field, permanent magnet arrays with different magnetic induction intensities can be selected. By replacing different arrays of permanent magnets, different magnetic field strengths can be adjusted.

[0053] It should be noted that the advantage of using permanent magnets is that there is no additional interference from an external electric field, but adjusting the magnetic field strength is more complicated. Using electromagnets, on the other hand, makes it easy to adjust the magnetic field strength, but an external electric field is present, which can affect the ultrasonic waves. The specific type of magnet used can be selected based on actual needs.

[0054] Based on the above embodiments, the target low-frequency AC signal is determined according to the combined ultrasonic signal corresponding to the three ultrasonic beams;

[0055] The ultrasonic signals corresponding to the three ultrasonic beams are as follows:

[0056]

[0057]

[0058]

[0059] The combined ultrasound signal is:

[0060]

[0061] Wherein, I is the combined ultrasonic signal that couples with a constant static magnetic field to generate the target AC signal; I1, I2, and I3 are the ultrasonic signals corresponding to the three ultrasonic beams; A1, A2, and A3 are the amplitudes corresponding to the three ultrasonic beams; and ω1, ω2, and ω3 are the angular frequencies corresponding to the three ultrasonic beams. and Let t represent the phase of the three ultrasonic beams, and t be the time.

[0062] Specifically, two alternating current signals with similar angular frequencies have small differences in angular frequency and satisfy Δω=(ω1-ω2)=(ω2-ω3)<<ω3<ω2<ω1. According to the interference principle of simple harmonic motion, the combined ultrasonic signal I formed by the mutual interference of I1, I2, and I3 at the target position, with an amplitude that slowly changes with time, can be expressed as:

[0063]

[0064] It should be noted that the explanation uses the two ultrasonic beams with the lowest angular frequencies as examples. Based on the condition that the angular frequency of an ultrasonic beam is Δω << ω2 < ω1, the first term in the above equation can be deduced. It can be regarded as having an angular frequency of Amplitude is The amplitude changes according to a cosine function and is always positive. Therefore, the frequency of the amplitude change is (ω1-ω2), meaning the combined vibration of I1 and I2 is a periodic motion with a slowly changing amplitude. Similarly, the combined vibration of I1 and I3 is a low-frequency signal with an amplitude frequency of (ω1-ω3), and the combined vibration of I2 and I3 is a low-frequency signal with an amplitude frequency of (ω2-ω3).

[0065] Based on the above embodiments, the induced current density of the target low-frequency AC signal at the target location is:

[0066]

[0067] Where, j x Let σ be the induced current density of the target low-frequency AC signal at the target location, ρ be the conductivity of the sample to be stimulated, ρ be the tissue density of the sample to be stimulated, c0 be the propagation speed of the ultrasound in the sample to be stimulated, and P be the electrical conductivity of the sample to be stimulated. y B is the ultrasonic pressure at the target location. z ωt is the magnetic field strength of the constant static magnetic field, sin(ωt) is the time function of the amplitude of the combined ultrasonic signal corresponding to the three ultrasonic beams, ω is the angular frequency of the amplitude of the combined ultrasonic signal changing with time, ω is also the angular frequency of the target low-frequency AC signal, and t is time.

[0068] It should be noted that the induced electric field and current of the target low-frequency AC signal are vector-like, and their directions are perpendicular to the combined sound field of the steady static magnetic field and the ultrasound. The magnitude of the induced current density is related to the conductivity σ of the sample to be stimulated, the tissue density ρ of the sample to be stimulated, the sound velocity c0 of the ultrasound in the sample to be stimulated, and the magnetic field strength B of the applied steady static magnetic field. z and the ultrasonic pressure P at the target location y All are relevant. Since ρ, c0, and σ are determined by the sample characteristics, while P... y Related to the sound pressure distribution characteristics of ultrasound, when the constant static magnetic field and the sample to be stimulated are determined, the distribution of the magnetoacoustic coupling induced electric field should be consistent with the distribution of the combined ultrasound signal sound field, and the current frequency should be comparable to the frequency of the combined ultrasound signal. Currently, the frequency of therapeutic focused ultrasound signals used is between 0.1 and 1 MHz, and the spatial resolution is between 1 and 2 mm. Therefore, the frequency of the induced current generated inside the tissue is also between 0.1 and 1 MHz, and the minimum focusing diameter of the stimulation current can reach 1 to 2 mm. However, for neurons, this electrical stimulation is a high-frequency stimulation (MHz level), which is difficult to induce a low-frequency response in neurons. By simultaneously using three focused ultrasound transducers that are perpendicular to each other in space, three independent ultrasound beams with similar frequencies are emitted and focused at a certain angle (90°) on the target location, and a spatially symmetrical, highly focused low-frequency electrical signal, i.e., the target low-frequency AC signal, is coupled out at this location, which can further improve the spatial resolution and application range of transcranial magnetoacoustic coupling stimulation.

[0069] The technical solution of this invention uses an ultrasonic transmitting module to emit three ultrasonic beams toward a target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency. A static magnetic field generating module generates a constant static magnetic field at the target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location. The magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module. This solves the problems of excessively high electrical signal frequency and poor focusing when inducing neuronal electrical activity, and achieves the effect of providing a spatially symmetrical, high-resolution low-frequency induced electric field and current to induce neuronal electrical activity.

[0070] Example 3

[0071] Based on the above embodiments, Figure 4 This is a schematic diagram illustrating the working principle of a low-frequency focused electrical stimulation device provided in Embodiment 3 of the present invention.

[0072] like Figure 4 As shown, the low-frequency focused electrical stimulation device of this embodiment includes: an ultrasonic wave emitting module, a static magnetic field generating module, and a fixing device.

[0073] The ultrasonic transmitting module is used to emit ultrasonic beams towards the target location of the sample to be stimulated. The ultrasonic transmitting module includes a three-channel pulsed ultrasonic excitation source and three independent focused ultrasonic transducers with similar center frequencies. In the ultrasonic transmitting module, the excitation channels of the pulsed ultrasonic excitation source correspond one-to-one with the single-element focused ultrasonic transducers, thereby exciting the focused ultrasonic transducers to emit ultrasonic beams with similar frequencies. The three ultrasonic beams are perpendicular to each other in space and intersect at a single point, which is the location of the stimulation target (target location).

[0074] The pulsed ultrasound excitation source is a three-channel pulsed ultrasound excitation source, capable of simultaneously exciting three focused ultrasound transducers to emit ultrasonic beams. The frequencies of the three excitation signals are not significantly different. The focused ultrasound transducers are single-element focused ultrasound transducers, each corresponding one-to-one with one of the three channels of the pulsed ultrasound excitation source. After being excited, they emit three ultrasonic signals that are perpendicular to each other in space. The center frequencies of the three ultrasonic beams are similar, and the frequency difference between the highest and middle frequencies is equal to the frequency difference between the middle and lowest frequencies. This difference is much smaller than the frequency of each individual ultrasonic beam.

[0075] Specifically, by adjusting the excitation parameters of the pulsed ultrasonic excitation source, the frequencies f1, f2, and f3 of the three excitation signals can be made to satisfy the following:

[0076] Δf = f1 - f2 = f2 - f3 << f3 <f2<f1

[0077] That is, the difference in center frequencies of the ultrasonic beams emitted by the three focused ultrasonic transducers is much smaller than that of each ultrasonic beam, so as to meet the conditions for the generation of the simple harmonic motion "interference" phenomenon.

[0078] The static magnetic field generating module is a permanent magnet assembly. The permanent magnet assembly consists of several groups of permanent magnets with different magnetic induction intensities. Each group contains two permanent magnets of the same size and with equal magnetic induction intensities, used to provide a constant static magnetic field. In use, the two permanent magnets in the same group are placed on either side of the sample to be stimulated, with the N pole of one permanent magnet facing the S pole of the other.

[0079] The fixing device is a universal cantilever bracket. The universal cantilever bracket consists of three non-ferromagnetic supports whose height and angle can be arbitrarily adjusted. These supports are used to fix the single-element focused ultrasound transducer, facilitating the adjustment of the direction and focal position of the ultrasound beams emitted by the transducer. This ensures that the three ultrasound beams are perpendicular to each other in space and converge at the target location of the sample to be stimulated. Furthermore, the propagation direction of the combined ultrasound beam generated by the convergence of the three beams needs to be perpendicular to the direction of the constant static magnetic field to ensure a sufficiently large induced electric field and current. Subsequently, based on the magnetoacoustic coupling effect, a spatially symmetrical, high-resolution low-frequency induced electric field and current will be generated in the sample to be stimulated within the ultrasound signal focusing region.

[0080] The technical solution of this embodiment emits three ultrasonic beams with similar center frequencies to the target location through an ultrasonic transmitting module. All three ultrasonic beams are focused on the target location of the sample to be stimulated and are at a 90-degree angle in space. The three ultrasonic beams interfere at the intersection to form a low-frequency signal. A static magnetic field generating module generates a stable static magnetic field at the target location. Based on the magnetoacoustic coupling effect, a low-frequency induced electric field and current perpendicular to both the direction of the combined sound field and the direction of the static magnetic field are coupled at the target location. This solves the problems of excessively high electrical signal frequency and poor focusing when inducing neuronal electrical activity, and achieves the effect of providing a spatially symmetrical, high-resolution low-frequency induced electric field and current to induce neuronal electrical activity.

[0081] Example 4

[0082] Figure 5 This is a flowchart illustrating a low-frequency focused electrical stimulation method provided in Embodiment 4 of the present invention. This embodiment is applicable to situations where a low-frequency alternating current signal is generated at the target location to be stimulated. The method can be executed by a low-frequency focused electrical stimulation device.

[0083] like Figure 5 As shown, the method in this embodiment specifically includes the following steps:

[0084] S410, based on the ultrasonic transmitting module, emits three ultrasonic beams toward the target location.

[0085] Among them, the three ultrasonic beams are perpendicular to each other and focused on the target position of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the signal frequency difference between two adjacent ultrasonic beams is equal to the preset interference frequency.

[0086] S420, based on the static magnetic field generation module, generates a constant static magnetic field at the target location, so that the constant static magnetic field and three ultrasonic beams generate a target low-frequency AC signal at the target location.

[0087] The direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module.

[0088] Based on the above embodiments, optionally, the ultrasonic transmitting module includes: a pulsed ultrasonic excitation source, a first ultrasonic transducer, a second ultrasonic transducer, and a third ultrasonic transducer; providing an ultrasonic excitation signal based on the pulsed ultrasonic excitation source; converting the ultrasonic excitation signal corresponding to the first ultrasonic transducer in the ultrasonic excitation source into a first ultrasonic wave based on the first ultrasonic transducer; converting the ultrasonic excitation signal corresponding to the second ultrasonic transducer in the ultrasonic excitation source into a second ultrasonic wave based on the second ultrasonic transducer; and converting the ultrasonic excitation signal corresponding to the third ultrasonic transducer in the ultrasonic excitation source into a third ultrasonic wave based on the third ultrasonic transducer; wherein the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave are perpendicular to each other.

[0089] Based on the above embodiments, optionally, the pulsed ultrasound excitation source is a three-channel pulsed ultrasound excitation source, and the first ultrasound transducer, the second ultrasound transducer and the third ultrasound transducer are all single-element focused ultrasound transducers.

[0090] Based on the above embodiments, optionally, the device further includes: a fixing module; based on the fixing module, the first ultrasonic transducer, the second ultrasonic transducer and the third ultrasonic transducer are fixed, and the positions and angles of the first ultrasonic transducer, the second ultrasonic transducer and the third ultrasonic transducer are adjusted.

[0091] Based on the above embodiments, optionally, the fixing module includes three non-ferromagnetic universal cantilever brackets; wherein the first ultrasonic transducer, the second ultrasonic transducer and the third ultrasonic transducer are respectively fixed on the non-ferromagnetic universal cantilever brackets; the height and angle of the non-ferromagnetic universal cantilever brackets are adjustable.

[0092] Based on the above embodiments, optionally, the center frequencies of the three ultrasonic beams satisfy the following condition:

[0093] Δf = f1 - f2 = f2 - f3 << f3 <f2<f1

[0094] Wherein, f1 is the highest frequency among the center frequencies of the three ultrasonic beams, f2 is the middle frequency among the center frequencies of the three ultrasonic beams, f3 is the lowest frequency among the center frequencies of the three ultrasonic beams, and Δf is the preset interference frequency, which is the difference between the highest frequency and the middle frequency, and also the difference between the middle frequency and the lowest frequency.

[0095] Based on the above embodiments, optionally, the static magnetic field generating module includes: at least two sets of permanent magnets, wherein each set of permanent magnets includes two permanent magnets of the same size and with matching magnetic induction intensity, and the N pole of the first permanent magnet and the S pole of the second permanent magnet in each set of permanent magnets are placed opposite each other.

[0096] Based on the above embodiments, optionally, the target low-frequency AC signal is determined according to the combined ultrasonic signal of the ultrasonic signals corresponding to the three ultrasonic beams;

[0097] The ultrasonic signals corresponding to the three ultrasonic beams are as follows:

[0098]

[0099]

[0100]

[0101] The combined ultrasound signal is:

[0102]

[0103] Wherein, I is the combined ultrasonic signal that couples with the constant static magnetic field to generate the target alternating current signal, I1, I2, and I3 are the ultrasonic signals corresponding to the three ultrasonic beams, A1, A2, and A3 are the amplitudes corresponding to the three ultrasonic beams, and ω1, ω2, and ω3 are the angular frequencies corresponding to the three ultrasonic beams. and Let t represent the phase of the three ultrasonic beams, and t represent time.

[0104] Based on the above embodiments, optionally, the induced current density of the target low-frequency AC signal at the target location is:

[0105]

[0106] Where, j x σ is the induced current density of the target low-frequency AC signal at the target location, σ is the conductivity of the sample to be stimulated, ρ is the tissue density of the sample to be stimulated, c0 is the propagation speed of ultrasound in the sample to be stimulated, and P is the induced current density of the target low-frequency AC signal at the target location. y B is the ultrasonic sound pressure at the target location. z The magnetic field strength of the constant static magnetic field is given by sin(ωt), which is the time function of the amplitude of the combined ultrasonic signal corresponding to the three ultrasonic beams, ω is the angular frequency of the amplitude of the combined ultrasonic signal changing with time, and ω is also the angular frequency of the target low-frequency AC signal, and t is time.

[0107] The technical solution of this invention uses an ultrasonic transmitting module to emit three ultrasonic beams toward a target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency. A static magnetic field generating module generates a constant static magnetic field at the target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location. The magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module. This solves the problems of excessively high electrical signal frequency and poor focusing when inducing neuronal electrical activity, and achieves the effect of providing a spatially symmetrical, high-resolution low-frequency induced electric field and current to induce neuronal electrical activity.

[0108] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A low-frequency focused electrical stimulation device, characterized in that, include: An ultrasonic transmitting module is used to emit three ultrasonic beams toward a target location. The three ultrasonic beams are perpendicular to each other and focused on the target location of the sample to be stimulated. The center frequencies of the three ultrasonic beams form an arithmetic sequence, and the signal frequency difference between two adjacent ultrasonic beams is equal to a preset interference frequency. A static magnetic field generating module is used to generate a constant static magnetic field at a target location, so that the constant static magnetic field and the three ultrasonic beams generate a target low-frequency alternating current signal at the target location, wherein the magnetic field direction of the constant static magnetic field is perpendicular to the resultant direction of the three ultrasonic beams emitted by the ultrasonic transmitting module.

2. The apparatus according to claim 1, characterized in that, The ultrasonic transmitting module includes: A pulsed ultrasonic excitation source is used to provide ultrasonic excitation signals; A first ultrasonic transducer is connected to the pulsed ultrasonic excitation source and is used to convert the ultrasonic excitation signal corresponding to the first ultrasonic transducer in the ultrasonic excitation source into a first ultrasonic wave. The second ultrasonic transducer is connected to the pulsed ultrasonic excitation source and is used to convert the ultrasonic excitation signal corresponding to the second ultrasonic transducer in the ultrasonic excitation source into a second ultrasonic wave. The third ultrasonic transducer is connected to the pulsed ultrasonic excitation source and is used to convert the ultrasonic excitation signal corresponding to the third ultrasonic transducer in the ultrasonic excitation source into a third ultrasonic wave. The first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave are perpendicular to each other.

3. The apparatus according to claim 2, characterized in that, The pulsed ultrasound excitation source is a three-channel pulsed ultrasound excitation source, and the first, second, and third ultrasound transducers are all single-element focused ultrasound transducers.

4. The apparatus according to claim 2, characterized in that, Also includes: A fixing module is used to fix the first ultrasonic transducer, the second ultrasonic transducer and the third ultrasonic transducer, and to adjust the position and angle of the first ultrasonic transducer, the second ultrasonic transducer and the third ultrasonic transducer.

5. The apparatus according to claim 4, characterized in that, Also includes: The fixing module includes three non-ferromagnetic universal cantilever brackets; wherein, the first ultrasonic transducer, the second ultrasonic transducer, and the third ultrasonic transducer are respectively fixed on the non-ferromagnetic universal cantilever brackets; the height and angle of the non-ferromagnetic universal cantilever brackets are adjustable.

6. The apparatus according to claim 1, characterized in that, The center frequencies of the three ultrasonic beams satisfy the following condition: in, The highest frequency among the center frequencies of the three ultrasonic beams. The middle frequency among the center frequencies of the three ultrasonic beams. The lowest frequency among the center frequencies of the three ultrasonic beams. The preset interference frequency is the difference between the highest frequency and the intermediate frequency, and it is also the difference between the intermediate frequency and the lowest frequency.

7. The apparatus according to claim 1, characterized in that, The static magnetic field generating module includes: At least two sets of permanent magnets, wherein each set of permanent magnets includes two permanent magnets of the same size and with matched magnetic induction intensity, and the N pole of the first permanent magnet and the S pole of the second permanent magnet in each set of permanent magnets are placed opposite each other.

8. The apparatus according to claim 1, characterized in that, The target low-frequency AC signal is determined based on the combined ultrasonic signal corresponding to the three ultrasonic beams; The ultrasonic signals corresponding to the three ultrasonic beams are as follows: The combined ultrasound signal is: in, To generate a combined ultrasonic signal by coupling with the constant static magnetic field to produce the target alternating current signal, , and The three ultrasonic beams correspond to the ultrasonic signals. , and The amplitudes corresponding to the three ultrasonic beams are given. , and The angular frequencies corresponding to the three ultrasonic beams are given. , and The phases corresponding to the three ultrasonic beams are denoted as . For time.

9. The apparatus according to claim 1, characterized in that, The induced current density of the target low-frequency AC signal at the target location is: in, The induced current density of the target low-frequency AC signal at the target location. The conductivity of the sample to be stimulated is... The tissue density of the sample to be stimulated. The speed at which ultrasound waves propagate in the sample to be stimulated. The ultrasonic sound pressure at the target location is [value missing]. The magnetic field strength of the constant static magnetic field is... The amplitude of the combined ultrasonic signal corresponding to the three ultrasonic beams is a time function that varies with time. The angular frequency of the combined ultrasonic signal amplitude as a function of time. It is also the angular frequency of the target low-frequency AC signal. For time.

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