Non-invasive deep brain neural focusing stimulation method and system based on parallel regulation of projection angles

Abstract

The application discloses a non-invasive deep brain nerve focusing stimulation method and system based on projection angle parallel control. The system comprises a multi-channel transcranial stimulation array, a phase parallel control module, a focusing control module, a nerve response monitoring module and a focusing optimization module. The method obtains the focusing position of the target deep brain area through the focusing control module, calculates the required phase distribution of each stimulation source and converts the phase distribution into a projection angle sequence θ_i; the phase parallel control module outputs all the projection angles to each stimulation source in parallel at the same clock edge; each stimulation source adjusts the initial phase of the radiation field, propagates in the brain tissue and coherently superimposes at the deep target position to form focusing. The application realizes electronic focusing stimulation of non-invasive deep brain nerves, the focusing depth can reach 6-8 cm, the scanning speed is greater than 1000 points / s, and can be widely applied to the non-invasive treatment of neurological and mental diseases such as Parkinson's disease and depression and the field of cognitive neuroscience research.

Description

Technical Field

[0001] This invention relates to the fields of neuromodulation and medical imaging technology, specifically to a non-invasive deep brain nerve focusing stimulation method and system based on parallel control of projection angle. This invention is particularly applicable to transcranial magnetic stimulation (TMS) deep focusing, transcranial electrical stimulation (TES) deep focusing, focused ultrasound deep brain stimulation, non-invasive treatment of mental illnesses, neurorehabilitation, and cognitive neuroscience research scenarios. Background Technology

[0002] Deep brain stimulation (DBS) is an effective treatment for neuropsychiatric disorders such as Parkinson's disease, treatment-resistant depression, and obsessive-compulsive disorder. However, traditional DBS requires invasive surgery to implant electrodes, posing risks such as intracranial hemorrhage, infection, and electrode displacement. Non-invasive DBS techniques eliminate the need for craniotomy, significantly reducing treatment risks and representing an important direction for the development of neuromodulation technology. However, current non-invasive DBS techniques have fundamental limitations in terms of focusing depth, spatial resolution, and targeting accuracy. Existing non-invasive deep brain stimulation techniques can be mainly divided into the following categories: (a) Single-coil transcranial magnetic stimulation An electric field is induced in the brain by a time-varying magnetic field generated by a single magnetic stimulation coil. This type of method has the following problems: (1) the magnetic field decays exponentially with depth, and the electric field strength in deep brain regions is extremely low; (2) the focusing area is in the superficial cortex, and it is impossible to accurately target deep nuclei; (3) deep stimulation requires extremely high pulse energy, which poses a safety hazard. (ii) Multi-coil transcranial magnetic stimulation Deep focusing is achieved through the coordinated operation of multiple coils. This type of method has the following problems: (1) The pulse timing of each coil is controlled serially, which makes it impossible to achieve precise phase synchronization; (2) It lacks the ability to adjust the multi-channel parallel phase, which makes it impossible to optimize the deep focusing effect; (3) The electromagnetic coupling interference between each coil is difficult to eliminate. (iii) Transcranial electrical stimulation The method modulates cortical excitability by applying a weak current through scalp electrodes. This type of method has the following problems: (1) the current is severely diffused in the skull and scalp; (2) deep focusing cannot be achieved; and (3) the spatial resolution is extremely low (centimeter level). (iv) Focused ultrasound deep brain stimulation Focused ultrasound is used to modulate neurons in deep brain regions by utilizing the mechanical effects of focused ultrasound. This type of method has the advantages of being non-invasive and having a large penetration depth, but it has the following problems: (1) the focal point position is determined by mechanical movement, which is slow; (2) it cannot achieve multifocal synchronous stimulation; and (3) it lacks phase encoding capability. (v) Intervention-focused transcranial stimulation In recent years, there have been explorations of using the interference effect of multiple stimulus sources to achieve focusing, but the existing schemes have the following problems: (1) the phase control of each stimulus source is done in a serial manner, which cannot achieve high-speed parallel configuration; (2) there is a lack of closed focusing feedback mechanism; (3) the focus point is difficult to scan in real time. In summary, the fundamental deficiency of existing non-invasive deep brain stimulation techniques lies in the lack of a non-invasive neurostimulation architecture capable of achieving multi-channel parallel phase modulation, deep focusing, and real-time scanning. This invention, for the first time, integrates a parallel phase modulation module with a multi-channel transcranial stimulation array, achieving non-invasive focused stimulation of deep brain nerves through parallel control of the projection angle. Summary of the Invention

[0003] (a) Purpose of the invention This invention provides a non-invasive deep brain nerve focusing stimulation method and system based on parallel control of projection angle, aiming to solve the technical problems of existing non-invasive neuromodulation techniques that cannot achieve deep focusing, have low spatial resolution, and lack parallel phase control. (II) Technical Principles This invention is based on beamforming theory and a phase-parallel computation architecture. In this invention, non-invasive deep brain nerve focused stimulation is achieved through the following physical chain: Interferometric focusing principle: Multiple stimulation sources (magnetic coils, electrodes, or ultrasonic transducers) are arranged in an array on the scalp surface. The physical fields (magnetic, electric, or acoustic fields) generated by each stimulation source propagate through the brain tissue. By precisely controlling the relative phase of each stimulation source, the field components are superimposed in phase at the deep target point (constructive interference), forming a local maximum field strength; while in other regions, they weaken each other due to phase inconsistency. Interferometric focusing can significantly increase the field strength at deep target points without increasing the total input power. Deep focusing conditions: The focusing depth is determined by the phase distribution of each stimulus source. Through parallel phase modulation, the field strength of deep targets can be maximized while maintaining the surface field strength without increasing it. The focusing depth can reach 6-8 cm, covering deep targets such as the subthalamic nucleus and nucleus accumbens. Parallel phase modulation: Each phase branch of the parallel phase modulation module outputs a projection angle θ_i, which drives each stimulus source in parallel on the same clock edge. The value of θ_i determines the initial phase of the radiation field of that stimulus source. By changing the phase distribution of each stimulus source, the focal point can move rapidly in three-dimensional space in deep brain regions. Focusing effect feedback: By acquiring neural signals or imaging feedback (such as functional near-infrared spectroscopy, electroencephalography) in real time, the neural response to focusing stimulation is monitored, and the projection angle distribution is dynamically adjusted to optimize the focusing effect. The fundamental difference from existing technologies: This invention is not a "single-source high-power stimulation" or "mechanical movement focusing" solution, but an electronic scanning method that achieves deep focusing through multi-source phase interference, which does not require mechanical movement and the focusing depth and position are completely determined by the phase distribution. (III) Technical Solution A non-invasive deep brain nerve focusing stimulation system based on parallel control of projection angle, characterized in that it comprises: A multi-channel transcranial stimulation array, comprising multiple stimulation sources (magnetic stimulation coils, electrical stimulation electrodes or ultrasound transducers), is placed on the scalp surface, with each stimulation source having an independent phase control terminal; The phase parallel modulation module contains multiple phase branches, each of which independently outputs a projection angle θ_i, which is connected to the phase control terminal of the corresponding stimulus source. A focusing control module, connected to the phase parallel modulation module, is used to calculate the required projection angle distribution of each stimulus source based on the deep focusing position of the target. The neural response monitoring module is used to collect neural response signals evoked by stimuli in real time. The focus optimization module, connected to the neural response monitoring module and the focus control module, is used to dynamically optimize the projection angle distribution based on neural response feedback. A non-invasive deep brain nerve focusing stimulation method based on parallel control of projection angle, characterized by comprising the following steps: S1: Obtain the focal position of the target deep brain region and calculate the phase distribution required for each stimulus source; S2: Convert the phase distribution into a corresponding projection angle sequence θ1, θ2, …, θ n ; S3: Through multiple phase branches of the phase parallel control module, the projection angle sequence is output to each stimulus source in parallel at the same clock edge; S4: Each stimulus source adjusts the initial phase of its radiation field according to the received projection angle θ_i; S5: The radiation fields of each stimulus source propagate in the brain tissue and coherently superimpose at the deep target location, forming constructive interference focusing; S6: The neural response monitoring module collects the neural responses induced by focused stimulation in real time, and the focusing optimization module dynamically adjusts the projection angle distribution according to the neural responses. (iv) Beneficial effects First, it achieves non-invasive deep brain nerve focused stimulation, with a focusing depth of 6-8cm, covering the main deep brain nuclei. Second, the focal point can be electronically scanned in three-dimensional space, and the scanning speed is 3-4 orders of magnitude faster than mechanical movement. Third, multi-source interferometric focusing can increase the field strength at deep target points and reduce the field strength at the scalp surface without increasing the total input power. Fourth, parallel phase modulation enables phase synchronization accuracy of each stimulus source to be better than 0.01 radians, significantly improving focusing accuracy. Fifth, the system has no moving mechanical parts, has high reliability, and is suitable for clinical applications. Detailed Implementation

[0004] Example 1 (Multi-coil transcranial magnetic stimulation for deep focusing) Step 1: Configure the phase parallel control module. The phase parallel control module is configured with 32 phase branches, each branch outputs a projection angle θ_i, with an update rate of 100MHz and an accuracy of 0.001 radians. Step 2: Deploy a multi-coil transcranial magnetic stimulation array. Thirty-two miniature magnetic stimulation coils are arranged on a helmet-style fixation device, covering the entire scalp area. Each coil is equipped with an independent drive circuit and a phase control terminal, which are connected to the phase branch one by one. Step 3: Calculate the deep focusing phase distribution. The focusing control module calculates the required phase distribution for each coil based on the target deep brain region (such as the left subthalamic nucleus, at a depth of approximately 7 cm). The finite-difference time-domain method is used to simulate the propagation of the magnetic field in brain tissue, optimizing the phase of each coil to maximize the field strength at the deep target point. Step 4: Parallel loading and focused stimulation. The phase parallel control module outputs 32 projection angles in parallel on the same clock edge, and each coil adjusts its phase simultaneously. A focused magnetic field is formed at the deep target point, and the field strength at the target point is more than 5 times higher than that of a single-coil TMS, while the field strength on the scalp surface is reduced by 30%. Step 5: Focus point 3D scanning. By rapidly updating the projection angle distribution, the focal point can scan along any trajectory in deep brain regions, enabling the creation of three-dimensional functional maps of deep brain regions. Example 2 (Transcranial Electrical Stimulation Deep Focusing) A multi-channel, high-density transcranial electrical stimulation electrode array (64 channels) is used to create a focused electric field in deep brain regions by controlling the current phase of each electrode. The focal point can be moved arbitrarily by electronic control without moving the electrodes. Example 3 (Focused Ultrasound Deep Brain Stimulation) A 256-element ultrasound transducer array is used, and the emission phase of each transducer is controlled in parallel to enable precise focusing of the ultrasound beam deep into the brain. The focal point size is approximately 2-3 mm, which is 5 times smaller than the diffraction limit of a single transducer. Example 4 (Deep Focused Closed-Loop Optimization) During focused stimulation, the neural responses evoked by the stimulus are monitored in real time using electroencephalography (EEG). Based on the EEG feedback signals, the focus optimization module automatically adjusts the projection angle distribution of each stimulus source using a gradient descent algorithm to maximize the neural response at deep target points. Attached Figure Description

[0005] Figure 1 This is a block diagram of the overall architecture of the non-invasive deep brain nerve focusing stimulation system based on parallel control of projection angle according to the present invention. Figure 2 This is a schematic diagram showing the corresponding connection between a multichannel transcranial stimulation array and a phase branch. Figure 3 This is a schematic diagram illustrating the focusing principle of deep brain interference. Figure 4 This is a flowchart of the deep brain nerve focused stimulation method of the present invention. Figure 5 This is a schematic diagram of a typical application scenario of the present invention. Terminology Explanation

[0006] Projection angle θ: The phase control parameter output by each phase branch. The value of θ determines the initial phase of the radiation field of the corresponding stimulus source, and the value ranges from -π to +π. Interferometric focusing: The technique of maximizing the field strength at the target point by controlling the phase of each wave source when the fields radiated by multiple wave sources are coherently superimposed in space. Transcranial magnetic stimulation (TMS): A non-invasive technique that uses external coils on the scalp to generate a time-varying magnetic field, which in turn induces an electric field in the brain to modulate neuronal activity. Transcranial electrical stimulation (TCS): A non-invasive technique that modulates the excitability of the cerebral cortex by applying a weak current through external electrodes on the scalp.

Claims

1. A non-invasive deep brain nerve focusing stimulation method based on parallel control of projection angle, characterized in that, Includes the following steps: S1: Obtain the focal position of the target deep brain region and calculate the phase distribution required for each stimulus source; S2: Convert the phase distribution into a corresponding projection angle sequence θ1, θ2, …, θ n ; S3: Through multiple phase branches of the phase parallel control module, the projection angle sequence is output to each stimulus source in parallel at the same clock edge; S4: Each stimulus source adjusts the initial phase of its radiation field according to the received projection angle θ_i; S5: The radiation fields of each stimulus source propagate in the brain tissue and coherently superimpose at the deep target location, forming a constructive interference focusing.

2. A non-invasive deep brain nerve focusing stimulation system based on parallel control of projection angle, characterized in that, include: A multi-channel transcranial stimulation array containing multiple stimulation sources is placed on the scalp surface, and each stimulation source has an independent phase control terminal. The phase parallel modulation module contains multiple phase branches, each of which independently outputs a projection angle θ_i, which is connected to the phase control terminal of the corresponding stimulus source. The focusing control module, connected to the phase parallel control module, is used to calculate the required projection angle distribution of each stimulus source based on the deep focusing position of the target.

3. The method according to claim 1, characterized in that, The stimulation source is at least one of a magnetic stimulation coil, an electrical stimulation electrode, or an ultrasonic transducer.

4. The method according to claim 1, characterized in that, The depth range of the focusing position is 3 cm to 8 cm.

5. The method according to claim 1, characterized in that, The three-dimensional spatial scanning speed of the focal point is greater than 1000 points / second.

6. The method according to claim 1, characterized in that, The phase synchronization accuracy of each stimulus source is better than 0.01 radians.

7. The system according to claim 2, characterized in that, It also includes a neural response monitoring module, which is used to collect neural response signals induced by stimuli in real time.

8. The system according to claim 7, characterized in that, It also includes a focus optimization module, connected to the neural response monitoring module and the focus control module, for dynamically optimizing the projection angle distribution based on neural response feedback.

9. The method according to claim 1, characterized in that, The method achieves multifocal synchronous deep stimulation through a non-uniform projection angle distribution.

10. The system according to claim 2, characterized in that, The multi-channel transcranial stimulation array is a headband or helmet-style fixation device that fits in contact with the scalp surface.

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