CN114366126A - A method and system for closed-loop EEG regulation - Google Patents

Abstract

The present application provides a closed-loop EEG regulation method and system. The method includes the following steps: receiving an EEG signal of an experimental subject; preprocessing the EEG signal to obtain a preprocessed EEG signal; calculating and processing the preprocessed brain signal electrical signal, obtain the theta rhythm EEG signal and EEG characteristic value; process the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm to set the stimulation phase; according to the ultrasonic stimulation The parameters and the theta rhythm set the stimulation phase, and ultrasonic stimulation was sent to the subject for EEG modulation. In the present application, the EEG signal of the experimental object is collected and analyzed in real time, and the closed-loop ultrasonic stimulation technology is used to realize the EEG regulation of the experimental object by using the EEG theta rhythm as a marker.

Description

A method and system for closed-loop electroencephalogram regulation

technical field

The present application relates to the technical field of ultrasonic stimulation nerve regulation, and in particular, to a closed-loop EEG regulation method and system.

Background technique

Brain nerve regulation technology is an important method to change the transmission of endogenous nerve signals in the brain by using external technical means such as light, magnetism, electricity, ultrasound and other physical or chemical means, thereby causing changes in brain function. Among them, ultrasonic neuromodulation is a new type of brain stimulation technology. Compared with other traditional electrical, magnetic and optical nerve stimulation technologies, it has the advantages of strong directionality, large penetration depth, accurate target control and non-invasiveness. Ultrasound non-invasive brain neuromodulation technology has attracted the attention of scholars in the field of neuroscience.

As a neuromodulation technology, ultrasound can be widely used in neuromodulation research in cells, rodents, non-human primates and humans, and is an ideal neuromodulation tool. However, unlike electrical stimulation neuromodulation techniques, in previous studies of transcranial ultrasound stimulation, the use of closed-loop ultrasound systems was rarely used, and the stimulation parameters could not be changed in real time according to the characteristics of the object during the stimulation process.

In addition, a very important rhythm in mammalian EEG is theta rhythm. Theta rhythm is generated by the local interaction of hippocampal interneurons and pyramidal neurons. Theta rhythm is important for many types of learning and memory processes. It also plays a key role in the regulation of synaptic plasticity. However, none of the existing closed-loop EEG regulation methods consider theta rhythm. To this end, the present application proposes a closed-loop EEG regulation method and system.

SUMMARY OF THE INVENTION

The purpose of this application is to provide a closed-loop EEG regulation method and system for the above problems.

In a first aspect, the present application provides a closed-loop EEG regulation method, the method includes the following steps:

Receive the EEG signals of the experimental subjects;

Preprocessing the EEG signal to obtain a preprocessed EEG signal;

Calculating and processing the preprocessed EEG signal to obtain the theta rhythm EEG signal and EEG characteristic value;

processing the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase;

The stimulation phase is set according to the ultrasonic stimulation parameters and the theta rhythm, and ultrasonic stimulation is sent to the experimental subject for EEG regulation.

According to the technical solutions provided by some embodiments of the present application, preprocessing the EEG signal to obtain the preprocessed EEG signal specifically includes the following steps:

The EEG signal is subjected to down-sampling, 50Hz notch denoising and 4-200Hz filtering to obtain a preprocessed EEG signal.

According to the technical solutions provided by some embodiments of the present application, calculating and processing the preprocessed EEG signal to obtain the theta rhythm EEG signal and EEG characteristic value, which specifically includes the following steps:

4-8Hz filtering is performed on the preprocessed EEG signal to obtain the theta rhythm EEG signal;

Calculate and process the preprocessed EEG signal and the theta rhythm EEG signal to obtain the EEG characteristic value.

According to the technical solutions provided by some embodiments of the present application, the theta rhythm EEG signal and the EEG characteristic value are processed to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase, which specifically includes the following steps:

Calculate the error between the EEG characteristic value and the preset expected value, and obtain ultrasonic regulation parameters according to the control strategy;

Calculate the theta rhythm phase of the theta rhythm EEG signal by using Hillbore transform;

The theta rhythm setting stimulation phase of the theta rhythm EEG signal is predicted according to the theta rhythm phase and the prediction model.

According to the technical solutions provided by some embodiments of the present application, the control strategy is a generalized minimum variance control strategy.

According to the technical solutions provided by some embodiments of the present application, the stimulation phase is set according to the ultrasonic stimulation parameters and the theta rhythm, and ultrasonic stimulation is sent to the experimental subject to perform EEG regulation, which specifically includes the following steps:

generating a first control waveform signal according to the ultrasonic stimulation parameters and the theta rhythm setting stimulation phase;

amplifying and processing the first control waveform signal to obtain a second control waveform signal;

enabling the second control waveform signal to be output as an ultrasonic signal;

The ultrasonic signal is confined within a set spatial range and emitted to the experimental subject.

In the second aspect, the present application provides a closed-loop EEG regulation system of the above-mentioned closed-loop EEG regulation method, including:

The processing module is configured to receive and preprocess the EEG signal of the experimental subject to obtain the preprocessed EEG signal, and is also configured to calculate and process the preprocessed EEG signal to obtain the theta rhythm EEG signal and the brain electrical characteristic value;

a control module, configured to process the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase;

The ultrasonic stimulation module is configured to set a stimulation phase according to the ultrasonic stimulation parameters and the theta rhythm, and send ultrasonic stimulation to the experimental subject to perform EEG regulation.

According to the technical solutions provided by some embodiments of the present application, the processing module includes:

a preprocessing module, configured to receive the EEG signal, and perform down-sampling, notch denoising and filtering processing on the EEG signal to obtain a preprocessed EEG signal;

The theta rhythm EEG calculation module, configured to filter the preprocessed EEG signal at 4-8 Hz to obtain the theta rhythm EEG signal;

The EEG feature value calculation module is configured to calculate and process the preprocessed EEG signal and the theta rhythm EEG signal to obtain the EEG feature value.

According to the technical solutions provided by some embodiments of the present application, the control module includes:

The theta rhythm phase prediction module, configured to calculate the theta rhythm phase of the theta rhythm EEG signal by adopting Hillbore transform, and also configured to predict the theta rhythm of the theta rhythm EEG signal according to the theta rhythm phase and the prediction model Set the stimulus phase;

The ultrasonic regulation parameter calculation module is configured to calculate the error between the EEG characteristic value and the preset expected value, and obtain the ultrasonic regulation parameter according to the control strategy.

According to the technical solutions provided by some embodiments of the present application, the ultrasonic stimulation module includes:

a signal generating module, configured to generate a first control waveform signal according to the ultrasonic stimulation parameters and the theta rhythm setting stimulation phase;

a power amplification module, configured to amplify and process the first control waveform signal to obtain a second control waveform signal;

an ultrasonic transducer module, configured to enable the second control waveform signal to be output as an ultrasonic signal;

The collimation module is configured to confine the ultrasonic signal within a set spatial range and transmit the ultrasonic signal to the experimental object.

Compared with the prior art, the beneficial effects of the present application: the closed-loop EEG regulation method provided by the present application includes: receiving the EEG signal of the experimental object; preprocessing the EEG signal to obtain the preprocessed EEG signal; The preprocessed EEG signal is described to obtain the theta rhythm EEG signal and the EEG characteristic value; the theta rhythm EEG signal and the EEG characteristic value are processed to obtain the ultrasonic stimulation parameters and the theta rhythm to set the stimulation phase; The ultrasonic stimulation parameters and the theta rhythm are set to stimulate the phase, and ultrasonic stimulation is sent to the experimental object for EEG regulation; the present application collects and analyzes the EEG signal of the experimental object in real time, and uses closed-loop ultrasonic stimulation technology to achieve The EEG theta rhythm was used as a marker to regulate the EEG of the experimental subjects.

The frequency band of theta rhythm is 4-8Hz, and the period is 125-250ms, which is convenient to ensure the stimulation accuracy in the closed-loop regulation of EEG in the presence of ms-level equipment operation delay. The closed-loop EEG regulation of electrical theta rhythm as a marker can further regulate the neural mechanisms and plastic neural pathways related to learning and memory, which is beneficial to study and improve the learning and memory and cognitive functions of experimental subjects.

Description of drawings

1 is a schematic structural diagram of a closed-loop EEG regulation system provided in Embodiment 1 of the present application;

2 is a flowchart of a closed-loop EEG regulation method provided in Embodiment 2 of the present application;

Fig. 3 is the concrete flow chart of step S3 in Fig. 2;

Fig. 4 is the concrete flow chart of step S4 in Fig. 2;

FIG. 5 is a specific flowchart of step S5 in FIG. 2 .

Detailed ways

In order to make those skilled in the art better understand the technical solutions of the present application, the present application will be described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the present application. .

Example 1

Referring to FIG. 1 , this embodiment provides a closed-loop EEG regulation system, which includes an acquisition module, a processing module, a control module, and an ultrasonic stimulation module.

The acquisition module is connected to the experimental object and is used for real-time acquisition of the EEG signal of the experimental object; wherein, the experimental object is set as a black mouse commonly used in experiments in the laboratory; the acquisition module includes EEG electrodes and neural signals processor; the EEG electrodes include three paths, one of which is inserted into the hippocampal CA1 area under the skull of the experimental object to record the EEG of the brain area, and the other two electrodes are inserted into the nasal bone of the experimental object as reference electrodes and the ground electrode; the neural signal processor is connected with the EEG electrode, and is configured to convert the EEG signal into a corresponding digital signal, and send the converted digital signal to the EEG signal processing module.

In this embodiment, the model of the neural signal processor can be selected by the Apollo II neural signal processor of Bio-Signal Technologies, the sampling frequency is 30 kHz, and it is connected to a PC through a USB interface.

The processing module, connected with the acquisition module, is used for receiving the EEG signal of the experimental object collected by the acquisition module, and preprocessing the EEG signal to obtain the preprocessed EEG signal, and is also configured to The pre-processed EEG signals are processed computationally to obtain theta rhythm EEG signals and EEG characteristic values.

Specifically, the processing module includes: a preprocessing module, a theta rhythm EEG calculation module, and an EEG feature value calculation module.

The preprocessing module is connected to the acquisition module, and is configured to receive the EEG signal, and perform down-sampling, 50Hz notch denoising and 4-200Hz filtering processing on the EEG signal to obtain preprocessing The EEG signal is further configured to send the preprocessed EEG signal to the theta rhythm EEG calculation module and the EEG feature value calculation module.

The theta rhythm EEG calculation module is configured to perform 4-8 Hz filtering on the preprocessed EEG signal to obtain the theta rhythm EEG signal, and is also configured to send the theta rhythm EEG signal to the EEG eigenvalue calculation module and the control module.

The EEG feature value calculation module is configured to calculate and process the preprocessed EEG signal and the theta rhythm EEG signal to obtain the EEG feature value, and is also configured to calculate the EEG feature value sent to the control module. The EEG characteristic value includes the absolute power of the preprocessed EEG signal, the relative power of the theta rhythm EEG signal relative to the preprocessed EEG signal, and the sample entropy.

The control module is configured to process the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase.

Specifically, the control module includes: a theta rhythm phase prediction module and an ultrasonic regulation parameter calculation module.

The ultrasonic regulation parameter calculation module is connected to the EEG characteristic calculation module, and is configured to calculate the error between the EEG characteristic value and the preset expected value, obtain ultrasonic regulation parameters according to the control strategy, and is also configured to The ultrasonic regulation parameters are sent to the ultrasonic stimulation module. Wherein, the ultrasonic regulation parameters include parameters such as ultrasonic size and duration.

The theta rhythm phase prediction module is connected to the theta rhythm EEG calculation module, and is configured to receive the theta rhythm EEG signal, and calculate the theta rhythm of the theta rhythm EEG signal using Hillbore transformation phase, and is also configured to predict the time of the theta rhythm to set the stimulation phase through the prediction model to obtain the ultrasonic stimulation time, and send the ultrasonic output instruction to the ultrasonic stimulation module according to the ultrasonic stimulation time; the theta rhythm prediction model can be based on the historical brain. The electrical theta rhythm predicts the theta rhythm phase in the future.

The control strategy can adjust the ultrasonic parameters according to the error between the current EEG characteristic value and the preset expected value, so as to achieve the effect of reducing or even eliminating the error; in this embodiment, the control strategy uses a generalized minimum variance control strategy , the theta rhythm phase prediction model is an AR model, and the theta rhythm sets the stimulus phase as a peak.

In this embodiment, the processing module and the control module are respectively implemented by a C++ program and a MATLAB program in the PC, and the data transmission between the C++ program and the MATLAB program is implemented by a UDP data packet.

The ultrasonic stimulation module is configured to set a stimulation phase according to the ultrasonic stimulation parameters and the theta rhythm, and send ultrasonic stimulation to the experimental subject to perform EEG regulation.

Specifically, the ultrasonic stimulation module includes: a signal generation module, a power amplification module, an ultrasonic transducer module and a collimation module.

The signal generation module is configured to receive the output instruction sent by the theta rhythm phase prediction module and the ultrasonic stimulation parameters sent by the regulation parameter calculation module, and generate a first control waveform signal.

The signal generating module is a function/arbitrary waveform generator that can remotely receive parameters such as ultrasonic frequency, pulse repetition frequency, pulse cycle number, pulse train length, pulse train interval, train cycle times, and start stimulation time in real time. , the signal generation module can optionally use the DG2080 model function/arbitrary waveform generator of the RIGOL brand, which is connected to the PC through the USB interface, and outputs the signal to the ultrasonic transducer through the BNC line, and the received control commands are generated by MATLAB program to send.

The power amplifying module is configured to amplify the first control waveform signal to obtain a second control waveform signal, and send the second control waveform signal to the super energy transducer module.

In this embodiment, the power amplifying module is implemented by a radio frequency amplifier. In this preferred embodiment, the power amplifier is a 240L ENI linear power amplifier.

The ultrasonic transducer module is configured to enable the second control waveform signal to be output as an ultrasonic signal, and is connected to the collimation module; the ultrasonic transducer module is an ultrasonic transducer, and the ultrasonic transducer A device is an active device that can realize the conversion of electrical power into mechanical power output, that is, a device that converts electrical energy into sound energy, and this process has only a small power loss (ultrasonic is a mechanical wave).

In this embodiment, the ultrasonic transducer generates ultrasonic waves, and its center frequency is set to 500 kHz, and an Olibas ultrasonic transducer with a diameter of 31 mm is selected, and the model is V301-SU.

The collimation module is fixedly connected to the output end of the ultrasonic transducer, and is configured to limit the ultrasonic signal within a set space range and transmit it to the experimental object, and at the same time, by filling the coupling fluid therein, Reduce the attenuation of ultrasound during propagation; in this embodiment, the collimation module is a collimator.

Example 2

This embodiment provides a closed-loop EEG regulation method using the closed-loop EEG regulation system described in Embodiment 1. FIG. 2 is a flowchart of the method, and the method includes the following steps:

S1. Receive the EEG signal of the experimental object.

In this embodiment, the experimental object is a black mouse commonly used in laboratory experiments.

S2. Preprocess the EEG signal to obtain a preprocessed EEG signal.

This step specifically includes: performing down-sampling, 50Hz notch denoising and 4-200Hz filtering processing on the EEG signal to obtain a pre-processed EEG signal.

S3. Calculate and process the preprocessed EEG signal to obtain the theta rhythm EEG signal and EEG characteristic value.

As shown in Figure 3, this step specifically includes:

S31, performing 4-8 Hz filtering on the preprocessed EEG signal to obtain the theta rhythm EEG signal;

S32. Calculate and process the preprocessed EEG signal and the theta rhythm EEG signal to obtain the EEG feature value.

S4. Process the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase.

As shown in Figure 4, this step specifically includes:

S41, calculating the error between the EEG characteristic value and the preset expected value, and obtaining ultrasonic regulation parameters according to the control strategy;

S42, using Hillbore transform to calculate the theta rhythm phase of the theta rhythm EEG signal;

S43. Predict the theta rhythm setting stimulation phase of the theta rhythm EEG signal according to the theta rhythm phase and the prediction model.

S5. Set a stimulation phase according to the ultrasonic stimulation parameters and the theta rhythm, and send ultrasonic stimulation to the experimental subject to perform EEG regulation.

As shown in Figure 5, this step specifically includes:

S51, setting a stimulation phase according to the ultrasonic stimulation parameters and the theta rhythm to generate a first control waveform signal;

S52. Amplify and process the first control waveform signal to obtain a second control waveform signal;

S53, enabling the second control waveform signal to be output as an ultrasonic signal;

S54. Confine the ultrasonic signal within a set space range and transmit it to the experimental object.

Specific examples are used herein to illustrate the principles and implementations of the present application, and the descriptions of the above embodiments are only used to help understand the methods and core ideas of the present application. The above are only the preferred embodiments of the present application. It should be pointed out that due to the limited expression of words, there are objectively unlimited specific structures. For those of ordinary skill in the art, without departing from the principles of the present invention However, some improvements, modifications or changes can also be made, and the above-mentioned technical features can also be combined in an appropriate manner; these improvements, modifications, or combinations, or the ideas and technical solutions of the invention are directly applied to other occasions without improvement. , shall be regarded as the protection scope of this application.

Claims (10)

1. a closed-loop brain electrical regulation method, is characterized in that, described method comprises the steps: Receive the EEG signals of the experimental subjects; Preprocessing the EEG signal to obtain a preprocessed EEG signal; Calculating and processing the preprocessed EEG signal to obtain the theta rhythm EEG signal and EEG characteristic value; processing the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase; The stimulation phase is set according to the ultrasonic stimulation parameters and the theta rhythm, and ultrasonic stimulation is sent to the experimental subject for EEG regulation. 2. The closed-loop EEG regulation method according to claim 1, characterized in that, preprocessing the EEG signal to obtain the preprocessed EEG signal, specifically comprising the following steps: The EEG signal is subjected to down-sampling, 50Hz notch denoising and 4-200Hz filtering to obtain a preprocessed EEG signal. 3. The closed-loop EEG regulation method according to claim 1, characterized in that, calculating and processing the preprocessed EEG signal to obtain theta rhythm EEG signal and EEG characteristic value, specifically comprising the steps: 4-8Hz filtering is performed on the preprocessed EEG signal to obtain the theta rhythm EEG signal; Calculate and process the preprocessed EEG signal and the theta rhythm EEG signal to obtain the EEG characteristic value. 4. The closed-loop EEG regulation method according to claim 1, wherein the θ rhythm EEG signal and the EEG characteristic value are processed to obtain ultrasonic stimulation parameters and the θ rhythm to set the stimulation phase, specifically It includes the following steps: Calculate the error between the EEG characteristic value and the preset expected value, and obtain ultrasonic regulation parameters according to the control strategy; Calculate the theta rhythm phase of the theta rhythm EEG signal by using Hillbore transform; The theta rhythm setting stimulation phase of the theta rhythm EEG signal is predicted according to the theta rhythm phase and the prediction model. 5 . The closed-loop EEG regulation method according to claim 4 , wherein the control strategy is a generalized minimum variance control strategy. 6 . 6. The closed-loop EEG regulation method according to claim 1, wherein the stimulation phase is set according to the ultrasonic stimulation parameters and the theta rhythm, and ultrasonic stimulation is sent to the experimental subject to carry out EEG regulation, specifically It includes the following steps: generating a first control waveform signal according to the ultrasonic stimulation parameters and the theta rhythm setting stimulation phase; amplifying and processing the first control waveform signal to obtain a second control waveform signal; enabling the second control waveform signal to be output as an ultrasonic signal; The ultrasonic signal is confined within a set spatial range and emitted to the experimental subject. 7. A closed-loop EEG regulation system of the closed-loop EEG regulation method according to any one of claims 1-6, characterized in that, comprising: The processing module is configured to receive and preprocess the EEG signal of the experimental subject to obtain the preprocessed EEG signal, and is also configured to calculate and process the preprocessed EEG signal to obtain the theta rhythm EEG signal and the brain electrical characteristic value; a control module, configured to process the theta rhythm EEG signal and the EEG characteristic value to obtain ultrasonic stimulation parameters and theta rhythm setting stimulation phase; The ultrasonic stimulation module is configured to set a stimulation phase according to the ultrasonic stimulation parameters and the theta rhythm, and send ultrasonic stimulation to the experimental subject to perform EEG regulation. 8. The closed-loop EEG regulation system according to claim 7, wherein the processing module comprises: a preprocessing module, configured to receive the EEG signal, and perform down-sampling, notch denoising and filtering processing on the EEG signal to obtain a preprocessed EEG signal; The theta rhythm EEG calculation module, configured to filter the preprocessed EEG signal at 4-8 Hz to obtain the theta rhythm EEG signal; The EEG feature value calculation module is configured to calculate and process the preprocessed EEG signal and the theta rhythm EEG signal to obtain the EEG feature value. 9. The closed-loop EEG regulation system according to claim 7, wherein the control module comprises: The theta rhythm phase prediction module, configured to calculate the theta rhythm phase of the theta rhythm EEG signal by using Hillbore transform, and also configured to predict the theta rhythm of the theta rhythm EEG signal according to the theta rhythm phase and the prediction model set stimulus phase; The ultrasonic regulation parameter calculation module is configured to calculate the error between the EEG characteristic value and the preset expected value, and obtain the ultrasonic regulation parameter according to the control strategy. 10. The closed-loop EEG regulation system according to claim 7, wherein the ultrasonic stimulation module comprises: a signal generating module configured to generate a first control waveform signal according to the ultrasonic stimulation parameters and the theta rhythm setting stimulation phase; a power amplification module, configured to amplify and process the first control waveform signal to obtain a second control waveform signal; an ultrasonic transducer module, configured to enable the second control waveform signal to be output as an ultrasonic signal; The collimation module is configured to confine the ultrasonic signal within a set spatial range and transmit the ultrasonic signal to the experimental object.

Images