A spatial phase encoding 40hz auditory stimulus sound field generation method and system

Abstract

The present application relates to a kind of based on spatial phase coding 40Hz hearing stimulus sound field generation method and system, comprising: S1, output gamma candidate frequency signal and obtain electroencephalogram response;S2, according to electroencephalogram determines 35-45Hz range individualized gamma stimulation frequency;S3, calculate corresponding period T;S4, generate basic gamma rhythm signal;S5, according to target spatial phase distribution determines the phase shift of each output unit φi, and calculate time offset τi=(φi / 360°)×T;S6, based on basic signal and φi, τi, gain gi, spatial weight wi, generate spatial phase coding gamma stimulation signal;S7, signal is output to multiple loudspeaker channel or spatial audio rendering system, forms the gamma rhythm sound field with the preset spatial phase relationship around 40Hz.The present application is characterized in that: solve the problem that the individual adaptation of existing 40Hz hearing stimulus technology is insufficient, multi-channel spatial phase relationship is uncontrollable, spatial stimulation mode is single and cannot be selected according to electroencephalogram response spatial sound field structure.

Description

Technical Field

[0001] This invention relates to the fields of neuroacoustics, auditory stimulation, multi-channel audio signal processing, and electroencephalogram (EEG) signal processing, specifically to a method and system for generating a 40Hz auditory stimulation sound field based on spatial phase coding. Background Technology

[0002] Gamma rhythm, also known as gamma rhythm or γ rhythm, is one of the important neural oscillatory rhythms in brain electrical activity. It is usually located in the frequency range of about 30Hz to 80Hz. Among them, the gamma rhythm near 40Hz is associated with brain functions such as attention, memory, cognitive processing, and neural network synchronization.

[0003] In recent years, inducing or enhancing gamma rhythm synchronization around 40Hz using external sensory stimulation has become an important research direction in neuroacoustics and brain science experiments. In existing studies, 40Hz sensory stimulation typically includes visual flickering stimulation, auditory rhythmic stimulation, and sound-light synchronized stimulation. Among these, auditory stimulation protocols can employ 40Hz amplitude-modulated sound, 40Hz click sound, short pulse sequences repeated at 40Hz, or sound-light synchronized 40Hz rhythmic stimulation.

[0004] However, existing 40Hz auditory stimulation technology still has many shortcomings.

[0005] First, existing methods typically fix the stimulation frequency at 40Hz or use preset stimulation parameters within a fixed frequency range, without fully considering individual differences among different target subjects in terms of gamma response peak, auditory threshold, EEG background state, and neural synchronization ability. Fixed 40Hz stimulation may not obtain a better EEG response in all target subjects.

[0006] Second, existing auditory stimulation schemes mostly use a single speaker, headphones, or dual-channel speaker to play 40Hz amplitude-modulated sound, click sound, or short pulse. The focus is on the stimulation frequency itself, rather than constructing a gamma rhythmic sound field with a definite phase relationship in multiple spatial directions. It is difficult to control the 40Hz phase, delay, sound pressure, and spatial weight relationship in different spatial orientations around the target object.

[0007] Third, although conventional multi-channel spatial audio technology can control the delay, phase, and gain of multiple speaker channels, its main purpose is usually sound image localization, sound field reconstruction, immersive listening experience, or spatial audio playback. It does not construct a neural rhythm stimulation sound field based on the gamma rhythm around 40Hz as the basic time unit. Therefore, it has not solved the problem of how to map individualized gamma cycles into multi-channel spatial phase structures.

[0008] Fourth, existing 40Hz auditory stimulation technologies typically do not select target spatial stimulation modes such as in-phase encirclement, left-right phase difference, front-back scanning, circular progression, or local enhancement based on the target subject's EEG response under different spatial stimulation modes, making it difficult to achieve adaptation between spatial stimulation structures and individual neural responses.

[0009] Therefore, there is an urgent need for a new method for generating auditory stimulation sound fields around 40Hz, which can determine the gamma stimulation parameters based on the individual EEG response of the target object, and further construct a gamma rhythmic sound field with a preset spatial phase relationship around the target object through multi-channel spatial phase encoding, thereby overcoming the shortcomings of existing fixed frequency, single source or dual-channel schemes in terms of individual adaptability and spatial structure control. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and system for generating a 40Hz auditory stimulation sound field based on spatial phase coding, so as to solve the problems of insufficient individual adaptability of stimulation frequency, uncontrollable multi-channel spatial phase relationship, single spatial stimulation mode, and inability to select spatial sound field structure according to EEG response in the existing 40Hz auditory stimulation technology.

[0011] To achieve the above objectives, a method for generating a 40Hz auditory stimulus sound field based on spatial phase coding is designed, comprising the following steps: S1, outputting auditory stimulus signals of one or more gamma candidate frequencies to the target object and acquiring the corresponding EEG response signal of the target object; S2, determining an individualized gamma stimulus frequency based on the EEG response signal, wherein the individualized gamma stimulus frequency is located in the range of 35Hz to 45Hz; S3, calculating the corresponding gamma stimulus period T based on the individualized gamma stimulus frequency; S4, generating a basic gamma rhythm auditory stimulus signal based on the individualized gamma stimulus frequency; S5, determining multiple output units in the same gamma range according to the target spatial phase distribution rule. S6. Calculate the phase shift parameter φi within the amma stimulation period T, and calculate the corresponding time shift parameter τi based on the phase shift parameter φi, where: τi = (φi / 360°) * T; S7. Generate a spatial phase-coded gamma stimulation signal based on the basic gamma rhythm auditory stimulation signal and the phase shift parameter φi, time shift parameter τi, gain parameter gi, and spatial weight parameter wi corresponding to each output unit; S8. Output the spatial phase-coded gamma stimulation signal to multiple speaker channels, or output it to a spatial audio rendering system and convert it into multiple speaker driving signals to form a 40Hz gamma rhythm sound field with a preset spatial phase relationship in the sound field area where the target object is located.

[0012] Preferably, the present invention further includes: the one or more gamma candidate frequencies include multiple frequency points in the range of 35Hz to 45Hz, the multiple frequency points include one or more of 38Hz, 39Hz, 40Hz, 41Hz and 42Hz; the EEG response signal is used to calculate one or more of the following indicators: gamma power gain, phase lock value, auditory steady-state response signal-to-noise ratio, brain region coherence, left and right hemisphere synchronicity, and to determine the individualized gamma stimulation frequency based on the one or more indicators.

[0013] Preferably, the present invention further includes: the basic gamma rhythm auditory stimulation signal includes one or more of the following: a short-tone pulse sequence, amplitude-modulated sound, narrowband noise-modulated sound, broadband noise-modulated sound, or composite carrier-modulated sound; the short-tone pulse sequence is formed by repeatedly outputting a carrier signal according to the individualized gamma stimulation frequency, the frequency range of the carrier signal is 500Hz to 8000Hz, the width of a single pulse is 0.5ms to 20ms, and the envelope of a single pulse includes one or more of the following: a rectangular window, a Hann window, a Gaussian window, an exponentially decaying window, a sinusoidal half-wave window, or a custom smooth envelope.

[0014] Preferably, the present invention further includes: the target spatial phase distribution rule includes one or more of the following: in-phase distribution rule, grouped phase difference rule, linear progressive phase rule, circular progressive phase rule, scanning phase rule, spherical layered phase rule, spherical rotational phase rule, radial convergence or divergence phase rule, spherical symmetry grouped phase rule, or dynamic update phase rule; under the in-phase distribution rule, the target neural rhythm phases corresponding to multiple output units are the same or substantially the same; under the grouped phase difference rule, there is a target neural rhythm phase difference between different output unit groups within the range of 0° to 180°; under the linear progressive phase rule, multiple output units are configured with sequentially increasing or decreasing target neural rhythm phases according to a straight line direction, an arc direction, or a preset spatial arrangement order; under the circular progressive phase rule, multiple output units arranged around the target object are configured with sequentially increasing or decreasing target neural rhythm phases according to a circular spatial order; under the scanning phase rule, output units located in different spatial directions of the target object output target neural rhythm stimulation signals according to a preset delay order to form a movement along a preset direction. The spatial rhythmic sound field; under the spherical layered phase rule, output unit groups located at different height layers or within different pitch angle ranges have a preset target neural rhythm phase difference; under the spherical rotation phase rule, multiple output units are configured with sequentially increasing or decreasing target neural rhythm phases according to the spatial arrangement order corresponding to the spherical path to form a spatial rhythmic sound field that progresses or rotates along the spherical path; under the radial convergence or divergence phase rule, multiple output units are configured with phase offset parameters and spatial weight parameters according to their spatial distribution relationship relative to the center position of the target object to form a spatial rhythmic sound field that converges towards the center region of the target object or diverges outward from the center region of the target object; under the spherical symmetric grouping phase rule, multiple output units are grouped according to their spatial partitions in a spherical, hemispherical, or approximately spherical array, with different spatial partitions corresponding to different target neural rhythm phase parameters; under the dynamic update phase rule, at least some output units' corresponding phase offset parameters φi, time offset parameters τi, gain parameters gi, or spatial weight parameters wi are updated with time, target spatial path, or EEG response indicators.

[0015] Preferably, the present invention further includes: the output unit includes one or more of a physical speaker channel, an audio object in a spatial audio rendering system, a virtual sound source, or a sound field control unit; the spatial phase-encoded gamma stimulus signal includes a speaker channel signal corresponding to the physical speaker channel, or includes an audio object signal, a virtual sound source signal, or a sound field control signal facing the spatial audio rendering system; the gamma rhythmic sound field near 40Hz is formed by direct output from a physical multi-speaker array, or by rendering the audio object signal, virtual sound source signal, or sound field control signal into multiple speaker drive signals through a wave field synthesis system, an object audio rendering system, or an array sound field synthesis system.

[0016] Preferably, the present invention further includes: the spatial phase-encoded gamma stimulus signal being output through a digital audio network, a multi-channel sound card, a multi-channel digital audio processor, or a multi-channel power amplifier system; the digital audio network includes one or more of Dante, AES67, RAVENNA, AVB, MADI, USB Audio, and Thunderbolt Audio.

[0017] Preferably, the present invention further includes: the target spatial phase distribution rule is determined based on the EEG response index of the target object under different spatial phase distribution rules, or one or more of the phase offset parameter φi, time offset parameter τi, gain parameter gi and spatial weight parameter wi are adjusted according to the real-time EEG response signal during stimulation.

[0018] Preferably, the present invention further includes: the spatial phase encoding method is also applicable to various target neural rhythm auditory stimuli, the target neural rhythm including delta rhythm, theta rhythm, alpha rhythm or beta rhythm; the system calculates the stimulation period T according to the target stimulation frequency corresponding to the target neural rhythm, and determines the phase offset parameter φi and time offset parameter τi of multiple output units according to the stimulation period T.

[0019] This invention also provides a 40Hz auditory stimulus sound field generation system based on spatial phase encoding, comprising: an EEG response acquisition module for acquiring EEG response signals of a target object at one or more gamma candidate frequencies; an individualized gamma frequency determination module for determining an individualized gamma stimulation frequency based on the EEG response signals and calculating the corresponding gamma stimulation period T; a basic stimulus signal generation module for generating a basic gamma rhythm auditory stimulus signal based on the individualized gamma stimulation frequency; a spatial phase encoding module for determining the phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi of multiple output units within the same gamma stimulation period T according to the target spatial phase distribution rules; a stimulus signal generation module for generating a spatial phase encoded gamma stimulus signal based on the basic gamma rhythm auditory stimulus signal and the phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi corresponding to each output unit; and a sound field output module for outputting the spatial phase encoded gamma stimulus signal to multiple speaker channels, or outputting it to a spatial audio rendering system and converting it into multiple speaker drive signals to form a gamma rhythm sound field near 40Hz.

[0020] Preferably, the present invention further includes: the spatial phase encoding module is used to generate spatial phase encoding parameters corresponding to in-phase distribution rules, grouped phase difference rules, linear progressive phase rules, circular progressive phase rules, scanning phase rules, or dynamically updated phase rules; the sound field output module includes a physical multi-speaker array output module, or includes a spatial audio rendering module; the spatial audio rendering module is used to convert audio object signals, virtual sound source signals, or sound field control signals into multiple speaker driving signals to form a spatialized gamma rhythmic sound field.

[0021] Compared with the prior art, the advantages of this invention are: This invention is not limited to a fixed 40Hz stimulus. Instead, it first outputs auditory stimulus signals of one or more gamma candidate frequencies to the target object and acquires the corresponding EEG response signals. Based on the EEG response signals, it determines an individualized gamma stimulus frequency within the range of 35Hz to 45Hz, thereby improving the individual adaptability of auditory stimulus parameters near 40Hz and solving the problem that fixed-frequency stimulation cannot obtain a better EEG response due to individual differences. This invention is not limited to single sound source, headphones, or dual-channel output. Instead, it uses a multi-channel spatial phase encoding matrix to assign gamma phase parameters, time offset parameters, gain parameters, and spatial weight parameters to multiple output units according to the target spatial phase distribution rules. Based on the basic gamma rhythm auditory stimulus signal, it generates a multi-channel spatial phase encoded gamma stimulus signal and outputs it to multiple speaker channels or a spatial audio rendering system, thereby forming a 40Hz gamma rhythm sound field with a preset spatial phase relationship around the target object. This invention enables various spatial stimulation modes, including in-phase distribution rules, grouped phase difference rules, linear progressive phase rules, circular progressive phase rules, scanning phase rules, spherical layered phase rules, spherical rotational phase rules, radial convergence or divergence phase rules, spherical symmetric grouped phase rules, and dynamically updated phase rules, giving gamma stimulation around 40Hz a well-defined programmable spatial structure. This invention can select the target spatial phase distribution rule based on the target object's EEG response indicators under different spatial phase distribution rules. It can also dynamically adjust one or more of the phase offset, time offset, gain, and spatial weight parameters during stimulation based on real-time EEG response signals, allowing the spatial stimulation structure to adapt to individual differences in neural responses and real-time changes in EEG state. This invention differs from traditional multi-channel spatial audio technology. Ordinary spatial audio primarily aims at sound image localization, sound field reconstruction, or immersive listening, while this invention targets gamma rhythmic stimulation around 40Hz, mapping individualized gamma cycles into a multi-channel spatial phase structure. Its purpose is not simply to improve spatial listening experience, but to form a rhythmic stimulation sound field with a preset gamma phase relationship through multi-channel spatial phase encoding. This invention is applicable to planar surround output unit arrangements, as well as spherical, hemispherical, multi-layered, or other three-dimensional spatial output unit arrangements, capable of forming a three-dimensional spatial phase-encoded target neural rhythm auditory stimulus sound field. Furthermore, the method of this invention is not only applicable to gamma rhythms around 40Hz, but can also be extended to delta rhythms, theta rhythms, alpha rhythms, beta rhythms, or other gamma rhythms, exhibiting broad application adaptability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall system structure of the present invention; Figure 2This is a schematic diagram of the method flow of the present invention; Figure 3 This is a schematic diagram of the process for determining the individualized gamma stimulation frequency according to the present invention; Figure 4 This is a schematic diagram of the multi-channel spatial phase encoding matrix of the present invention; Figure 5 This is a schematic diagram of a typical spatial stimulation pattern of the present invention; Figure 6 This is a schematic diagram of the multi-channel time offset within the same gamma period of the present invention; Figure 7 This is a schematic diagram illustrating the selection of target spatial stimulation patterns based on EEG response according to the present invention; Figure 8 This is a schematic diagram of the real-time spatial phase adjustment process of the present invention; Figure 9 This is a schematic diagram of the three-dimensional spatial phase encoding mode of the present invention under spherical, hemispherical or near-spherical output unit arrays. Detailed Implementation

[0023] To make the purpose, principle and structure of the present invention clearer, the following description is provided in conjunction with the accompanying drawings and specific embodiments.

[0024] See Figures 1 to 9 This invention provides a method and system for generating a 40Hz auditory stimulus sound field based on spatial phase encoding, such as... Figure 1 System overall structure diagram and Figure 2As shown in the flowchart, the spatial phase-encoded 40Hz auditory stimulus sound field generation method of the present invention first executes step S1: outputting one or more gamma candidate frequency auditory stimulus signals to the target object and acquiring the corresponding EEG response signal of the target object. The EEG response signal includes an EEG signal (Electroencephalography signal), which refers to the spontaneous electrical activity of the brain recorded from the scalp or intracranial cavity through electrodes, reflecting the synchronous rhythmic activity of neurons in the cerebral cortex, including spontaneous rhythms in multiple frequency bands such as δ, θ, α, β, and γ. In one specific embodiment, the system first acquires the baseline EEG signal of the target object in a resting state. Subsequently, the system selects multiple candidate frequency points in the range of 35Hz to 45Hz, preferably including five frequency points: 38Hz, 39Hz, 40Hz, 41Hz, and 42Hz, and generates corresponding candidate auditory stimulus signals. The duration of each candidate stimulus signal can be set from 30 seconds to 180 seconds according to the experimental design to ensure a stable EEG response. Candidate auditory stimulation signals can be short tone pulse sequences with a 1kHz carrier and a pulse width of 1ms to 5ms, or pure tones, narrowband noise, or broadband noise signals modulated by a gamma rhythm envelope around 40Hz. Simultaneously with the output of each candidate stimulation signal, the system records the target subject's EEG response signal using an EEG acquisition device.

[0025] Next, step S2 is performed: the individualized gamma stimulation frequency is determined based on the EEG response signal, wherein the individualized gamma stimulation frequency is in the range of 35Hz to 45Hz. Figure 3 The process for determining the individualized gamma stimulation frequency is illustrated. The system preprocesses and performs time-frequency analysis on the acquired EEG response signals, calculating the corresponding EEG response indices for each candidate frequency. Specifically, the EEG response signals are used to calculate one or more of the following indices: gamma power gain, phase locking value (PLV), auditory steady-state response (ASSR) signal-to-noise ratio, brain region coherence, and left-right hemisphere synchronicity. The individualized gamma stimulation frequency is then determined based on a comprehensive analysis of these indices.

[0026] Gamma power gain refers to the increase in the power spectral density of the EEG signal in the corresponding gamma band (e.g., 35-45Hz) relative to the resting baseline when the target subject receives auditory stimulation at candidate frequencies. It reflects the intensity of the synchronous neural activity induced by the stimulus. Phase lock value (PLV) measures the phase consistency of the EEG signal. It is calculated as the average vector length of the instantaneous phase difference of the EEG signal at the stimulation frequency over multiple stimulation cycles or trials. The PLV value ranges from 0 to 1; a higher value indicates stronger phase lock, i.e., better synchronization between the neural response and the stimulation rhythm. Auditory steady-state response (ASSR) is the steady-state evoked potential generated by the brain in response to periodic auditory stimulation. Its signal-to-noise ratio (ASSR SNR) is defined as the ratio of the amplitude of the EEG response at the stimulation frequency and its harmonics to the amplitude of noise in adjacent frequency bands. Specifically, in the implementation of Example 1, the system outputs auditory stimuli at five candidate frequencies: 38Hz, 39Hz, 40Hz, 41Hz, and 42Hz, and simultaneously acquires the target subject's EEG signal. For each candidate frequency, the system calculates the corresponding gamma power gain, PLV, and ASSR signal-to-noise ratio. If all three metrics are significantly higher than other frequencies at a given candidate frequency, or if the overall weighted score is the highest, then the system determines that frequency as the individualized gamma stimulation frequency fγ. The calculation of these metrics can be integrated into the individualized gamma frequency determination module to provide the optimal stimulation frequency for subsequent spatial phase encoding.

[0027] Step S3: Calculate the corresponding gamma stimulation period T based on the individualized gamma stimulation frequency. When the individualized gamma stimulation frequency fγ is 40Hz, the corresponding stimulation period T is 25ms; when fγ is 41Hz, T is approximately 24.39ms; when fγ is 39Hz, T is approximately 25.64ms. Step S4: Generate a basic gamma rhythm auditory stimulation signal based on the individualized gamma stimulation frequency. In a specific embodiment, the basic gamma rhythm auditory stimulation signal includes one or more of the following: short-tone pulse sequence, amplitude-modulated sound, narrowband noise-modulated sound, broadband noise-modulated sound, or composite carrier-modulated sound. When a short-tone pulse sequence is used, the sequence is formed by repeatedly outputting a carrier signal according to the individualized gamma stimulation frequency. The frequency range of the carrier signal can be selected from 500Hz to 8000Hz, for example, using a 1000Hz pure tone as the carrier. The width of a single pulse is set to 0.5ms to 20ms, preferably 1ms to 5ms. To reduce transient stimulation, the envelope of a single pulse can be one or more of the following: rectangular window, Hann window, Gaussian window, exponentially decaying window, sinusoidal half-wave window, or a custom smooth envelope. For example, a Hann window can be used to shape the envelope of each short tone pulse. When amplitude-modulated sound is used, the system uses an individualized gamma stimulation frequency fγ as the modulation frequency to perform amplitude modulation on pure tones, narrowband noise, broadband noise, or composite carriers. The modulation depth can be set from 80% to 100%.

[0028] Step S5: Based on the target space phase distribution rule, determine the phase offset parameter φi of multiple output units within the same gamma stimulation period T, and calculate the corresponding time offset parameter τi based on the phase offset parameter φi, where τi = (φi / 360°) × T. The output units include one or more of the following: physical speaker channels, audio objects in a spatial audio rendering system, virtual sound sources, or sound field control units. The target space phase distribution rule can be one or more of the following: in-phase distribution rule, grouped phase difference rule, linear progressive phase rule, circular progressive phase rule, scanning phase rule, spherical layered phase rule, spherical rotational phase rule, radial convergence or divergence phase rule, spherical symmetric grouped phase rule, or dynamically updated phase rule. Figure 4The structure of the multi-channel spatial phase encoding matrix is ​​shown. The matrix includes the phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi for each output unit. Step S6: Based on the basic gamma rhythm auditory stimulus signal and the corresponding phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi for each output unit, a spatial phase encoded gamma stimulus signal is generated. Step S7: The spatial phase encoded gamma stimulus signal is output to multiple speaker channels, or output to a spatial audio rendering system and converted into multiple speaker drive signals, so that a 40Hz gamma rhythm sound field with a preset spatial phase relationship is formed around the target object. The spatial phase encoded gamma stimulus signal can be output through one or more digital audio networks such as Dante, AES67, RAVENNA, AVB, MADI, USB Audio, and Thunderbolt Audio, or through a multi-channel sound card, a multi-channel digital audio processor, or a multi-channel power amplifier system.

[0029] In a specific implementation, the spatial phase-encoded gamma stimulus signal can be a multi-channel speaker signal directly corresponding to a physical speaker, or a driving signal rendered by a wave field synthesis system, an object audio rendering system, or an array sound field synthesis system. For example, the system generates one or more audio object signals with spatial position, motion trajectory, phase offset, time offset, and gain parameters, which are then converted into corresponding speaker driving signals by the spatial audio rendering system. Furthermore, the method of this invention is not only applicable to gamma rhythmic auditory stimulation around 40Hz, but can also be extended to other target neural rhythms, such as delta rhythms (0.5~4Hz), theta rhythms (4~8Hz), alpha rhythms (8~12Hz), or beta rhythms (12~30Hz). In this case, the system calculates the stimulation period T based on the target stimulus frequency corresponding to the target neural rhythm, and determines the phase offset parameters and time offset parameters of multiple output units using the same method, thereby forming a spatial phase-encoded sound field for the corresponding rhythm.

[0030] The phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi are all determined according to a pre-selected target spatial phase distribution rule. Target spatial phase distribution rules include various types such as in-phase distribution rules, grouped phase difference rules, linear progressive phase rules, circular progressive phase rules, scanning phase rules, and spherical layered phase rules, each corresponding to different parameter value methods. For example, under the same distribution rule, all output units are configured with the same or essentially the same φi value, typically 0°; under the circular progressive rule, adjacent output units are configured with a fixed phase increment according to the circular spatial arrangement of the speakers around the target object, such as an increase of 22.5° between adjacent units, thus forming a sequentially increasing φi sequence; under the left-right phase difference rule, the speaker group on the left is configured with 0°, and the group on the right with 180°, thereby obtaining the φi of each output unit.

[0031] After obtaining φi, the time offset parameter τi is directly calculated using the formula τi=φi / 360°×T, where T is the individualized gamma stimulation period. For example, when T=25ms (corresponding to 40Hz) and φi=90°, τi=90 / 360×25ms=6.25ms. The gain parameter gi is used to control the output sound pressure level of each output unit and can be determined according to the energy distribution requirements in different spatial directions in the target spatial stimulation mode. For example, in the in-phase envelopment mode, the gi of all channels can be set to the same value. Under a specific spatial phase distribution rule, different gi values ​​can be set for the output units corresponding to the target direction or target spatial partition. The spatial weight parameter wi is used to characterize the participation degree or spatial distribution priority of each output unit in the overall spatial sound field. It can be set in conjunction with gi and can also be used for object weight calculation in the subsequent spatial audio rendering system. All of the above parameters can be pre-stored as parameter templates corresponding to the target spatial phase distribution rule, or can be dynamically adjusted during stimulation based on real-time EEG response indicators.

[0032] The present invention also provides a spatial phase-encoded 40Hz auditory stimulus sound field generation system, the specific implementation of which corresponds to the above method, and the system specifically includes the following modules.

[0033] The EEG response acquisition module is used to acquire the EEG response signals of the target object at one or more gamma candidate frequencies.

[0034] The individualized gamma frequency determination module is used to determine the individualized gamma stimulation frequency based on the EEG response signal and calculate the corresponding gamma stimulation period T.

[0035] The basic stimulus signal generation module is used to generate basic gamma rhythmic auditory stimulus signals based on individualized gamma stimulus frequencies.

[0036] The spatial phase encoding module is used to determine the phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi of multiple output units according to the target spatial phase distribution rules.

[0037] The stimulation signal generation module is used to generate a spatial phase-coded gamma stimulation signal based on the basic gamma rhythm auditory stimulation signal and the parameters of each output unit.

[0038] The sound field output module includes a multi-channel audio output module and a speaker array connected to it for outputting the signal to multiple speaker channels or a spatial audio rendering system to form a gamma rhythmic sound field around 40Hz.

[0039] The spatial phase encoding module can generate encoding parameters corresponding to the aforementioned rules such as in-phase distribution, grouped phase difference, linear progression, circular progression, scanning phase, or dynamically updated phase. The sound field output module includes a physical multi-speaker array output module or a spatial audio rendering module, wherein the spatial audio rendering module is used to convert audio object signals, virtual sound source signals, or sound field control signals into multiple speaker drive signals.

[0040] Preferably, the system further includes a spatial pattern selection module connected to the spatial phase encoding module. After determining the individualized gamma stimulation frequency, the system sequentially outputs stimulation sound fields corresponding to various target spatial phase distribution rules, such as in-phase distribution, grouped phase difference, circular progression, and scanning phase. It also collects the EEG response signals of the target object under different spatial patterns and calculates indicators such as gamma power gain, phase lock value, auditory steady-state response signal-to-noise ratio, and left-right hemisphere synchronicity. The spatial pattern selection module automatically selects the spatial stimulation pattern with the best response based on the above indicators and sends the selected pattern parameters to the spatial phase encoding module. The latter generates corresponding phase offset parameters, time offset parameters, gain parameters, and spatial weight parameters accordingly, thereby achieving adaptive matching between the spatial stimulation structure and the individual neural response.

[0041] The following section uses several typical spatial stimulation patterns as examples to explain in detail the specific implementation of steps S5 to S7. Figure 5 Typical spatial stimulation patterns, such as the in-phase encirclement pattern and the left-right phase difference pattern, were demonstrated.

[0042] Figure 6Using a single gamma stimulation period T as the time reference, the trigger time offset relationship of the four output channels CH1 to CH4 within the same period is shown: each channel is delayed by a fixed time increment relative to the previous channel, so that the stimulation signals of the four channels are uniformly staggered on the time axis. By mapping the precise period T of the gamma rhythm to a controllable delay between multiple channels, speakers at different spatial locations can sequentially excite stimulation pulses, thereby forming a 40Hz rhythmic sound field with a clear directional progression or rotational feel around the target object; this method can be used to realize spatial stimulation patterns such as ring-shaped progressive phase rules and scanning phase rules, enhancing the directional modulation effect of neural rhythms in space.

[0043] Example 1: Determination of individualized gamma stimulation frequency.

[0044] like Figure 2 and Figure 3 As shown, the system first acquires the baseline EEG signal of the target subject in a resting state. Subsequently, the system generates candidate auditory stimulation signals at five candidate frequencies: 38Hz, 39Hz, 40Hz, 41Hz, and 42Hz. Each candidate stimulation signal can last from 30 seconds to 180 seconds.

[0045] The candidate auditory stimulus signal can be a short tone pulse sequence with a 1kHz carrier and a pulse width of 1ms to 5ms, or it can be a pure tone, narrowband noise, or broadband noise signal modulated by a gamma rhythm envelope around 40Hz.

[0046] While outputting each candidate stimulus signal, the system simultaneously acquires the target subject's EEG response signal and calculates the gamma power gain, phase lock value, auditory steady-state response signal-to-noise ratio, and brain region coherence corresponding to each candidate frequency. Based on these indicators, the system determines the individualized gamma stimulation frequency fγ. For example, if the target subject exhibits a high gamma power gain and phase lock value under 41Hz stimulation, the system can determine 41Hz as the individualized gamma stimulation frequency for that target subject.

[0047] Example 2: Generation of basic gamma rhythm auditory stimulus signals.

[0048] The system calculates the gamma stimulation period T based on the individualized gamma stimulation frequency fγ. When fγ is 40 Hz, T is 25 ms; when fγ is 41 Hz, T is approximately 24.39 ms. The system generates a basic gamma rhythmic auditory stimulation signal based on this period.

[0049] In one implementation, the basic gamma rhythm auditory stimulus signal is a sequence of short tone pulses. The short tone pulses may use a carrier frequency in the range of 500 Hz to 8000 Hz, and the width of a single pulse may be 0.5 ms to 20 ms. To reduce the perception of transient stimulation, the system may apply a Hann window, a Gaussian window, an exponentially decaying window, a sine half-wave window, or other smooth envelopes to the short tone pulses.

[0050] In another embodiment, the basic gamma rhythmic auditory stimulus signal is an amplitude-modulated sound. The system uses an individualized gamma stimulus frequency fγ as the modulation frequency to amplitude modulate pure tones, narrowband noise, broadband noise, or composite carrier waves.

[0051] Example 3: Generation of multi-channel spatial phase encoding matrix.

[0052] like Figure 4 As shown, the system generates a multi-channel spatial phase encoding matrix M based on the target spatial stimulus pattern. The matrix M can be represented as: M={φi,τi,gi,wi}.

[0053] Where i represents the output unit number, and the output unit can be a physical speaker channel, or an audio object or sound field control unit in a spatial audio rendering system; φi represents the gamma phase offset parameter of the i-th output unit, τi represents the time offset parameter of the i-th output unit, gi represents the gain parameter of the i-th output unit, and wi represents the spatial weight parameter of the i-th output unit.

[0054] Wherein, τi can be calculated according to the following relationship: τi=φi / 360°×T.

[0055] Where T is the gamma stimulation period corresponding to the individualized gamma stimulation frequency.

[0056] The system maps the basic gamma rhythm auditory stimulus signal into multiple output signals based on the multi-channel spatial phase encoding matrix. These output signals can be speaker channel signals directly corresponding to physical speakers, or audio object signals or sound field control signals for a spatial audio rendering system. Each output signal can have independent gamma phase, time offset, gain, and spatial weight, thereby forming a gamma rhythmic sound field with a preset phase relationship in space.

[0057] In one implementation, the system directly generates multiple speaker channel signals and outputs them through these channels to form a spatialized gamma rhythmic sound field. In another implementation, the system generates one or more audio object signals with spatial location, motion trajectory, phase offset, time offset, and gain parameters, and a spatial audio rendering system renders these audio object signals into corresponding speaker drive signals. The spatial audio rendering system may include a wave field synthesis system, an object audio rendering system, an array sound field synthesis system, or other multi-speaker spatial sound field reconstruction systems.

[0058] Through the above methods, the present invention can be applied to both traditional multi-channel loudspeaker arrays and spatial sound field realization methods based on audio objects or wave field synthesis.

[0059] Example 4: In-phase encirclement mode like Figure 5 As shown, in the in-phase envelopment mode, the gamma rhythmic stimulation signals output by multiple speaker channels have the same or substantially the same phase shift parameters.

[0060] For example, the system uses eight speakers arranged around the target object. All speaker channels output gamma rhythmic stimulation signals around 40Hz with the same phase within the same gamma cycle, creating a stable, enveloping gamma stimulation sound field around the target object. This mode is suitable for scenarios requiring improved overall spatial coverage and stimulation stability.

[0061] Example 5: Left and Right Phase Difference Mode In the left-right phase difference mode, there is a preset gamma phase difference between the speaker channel group located on the left side of the target object and the speaker channel group located on the right side of the target object.

[0062] For example, when the individualized gamma stimulation frequency fγ is 40Hz, one gamma cycle T is 25ms. If a 180° phase difference is set between the left and right speaker groups, the corresponding time offset is 12.5ms. This mode can form a gamma rhythmic sound field with phase differences in the left and right directions, which can be used to construct the phase relationship between different half-spaces.

[0063] Example 6: Circular Progressive Mode In the ring-progressive mode, multiple speaker channels are arranged in a ring around the target object. The system configures phase offset parameters for each speaker channel in a sequentially increasing or decreasing manner according to the spatial arrangement of the speakers.

[0064] For example, when 16 speaker channels are arranged in a ring, a gamma phase difference of 22.5° can be set between adjacent speaker channels. When the individualized gamma stimulation frequency fγ is 40Hz, the 22.5° phase difference corresponds to a time offset of approximately 1.5625ms. By changing the direction of phase increment or decrement, the progression direction of the spatial gamma rhythmic sound field can be altered.

[0065] Example 7: Front and Back Scan Mode In front-and-back scanning mode, the speaker channels located in front of, to the side of, and behind the target object output gamma rhythm stimulation signals in a preset delay sequence.

[0066] For example, the front speaker group first outputs a gamma rhythmic stimulus signal, the side speaker group outputs it after a delay of several milliseconds, and the rear speaker group outputs it after a further delay, thus forming a spatial gamma stimulus wavefront moving from front to back. By adjusting the time offset parameters between the speaker groups, the system can also form spatial gamma stimulus wavefronts moving from back to front, from left to right, from right to left, or in other directions.

[0067] Example 8: Target Spatial Stimulation Pattern Selection Based on EEG Response like Figure 7 As shown, the system can not only determine the individualized gamma stimulation frequency based on the EEG response, but also select the target spatial stimulation mode based on the target object's EEG response under different spatial stimulation modes.

[0068] The system can sequentially output gamma rhythmic sound fields in in-phase surround mode, left-right phase difference mode, circular progressive mode, and front-back scan mode, and acquire the target object's EEG response for each mode. The system calculates gamma power gain, phase lock value, auditory steady-state response signal-to-noise ratio, left-right hemisphere synchronicity, and brain region coherence for different spatial stimulation modes. If the EEG response indicators corresponding to a certain spatial stimulation mode are superior to those of other modes, the system can identify that spatial stimulation mode as the target spatial stimulation mode.

[0069] Example 9: Real-time Spatial Phase Adjustment like Figure 8 As shown, the system continuously acquires the target object's EEG response signal during stimulation and dynamically adjusts the multi-channel spatial phase encoding matrix based on the real-time EEG response.

[0070] For example, when the system detects a decrease in gamma power or a decrease in phase lock value, the phase offset parameter, time offset parameter, or gain parameter of some speaker channels can be adjusted; when the system detects insufficient synchronization between the left and right hemispheres, the phase difference between the left and right speaker groups can be adjusted; when the system detects a weak response in the ring progressive mode, it can switch to the in-phase surround mode or the front and back scan mode.

[0071] Example 10: Implementation of Multi-channel Audio Output The system can output multi-channel spatial phase-encoded gamma stimulation signals to multiple speaker channels via a multi-channel digital audio link. The multi-channel digital audio link may include Dante, AES67, RAVENNA, AVB, MADI, USBAudio, Thunderbolt Audio, a multi-channel sound card, a multi-channel digital audio processor, a multi-channel power amplifier system, or a combination thereof.

[0072] The loudspeakers can be positioned in front of, behind, to the left, to the right, above, below, or in a combination thereof on the target object. The number of loudspeakers can be 4, 8, 16, 24, 32, 64, or other quantities. The specific number of loudspeakers, spatial arrangement, output link, and driving method can be selected according to the experimental site, equipment conditions, and application scenario.

[0073] In one implementation, the system directly generates multi-channel output signals that correspond one-to-one with each physical loudspeaker, and forms a gamma rhythmic sound field with in-phase surround, left-right phase difference, front-back scanning, ring rotation, or local enhancement through the loudspeaker array.

[0074] In another implementation, the system generates an audio object signal for the spatial audio rendering system. The audio object signal may include one or more of the following: object audio content, object spatial location, object motion path, gamma phase offset parameter, time offset parameter, gain parameter, and spatial weight parameter. The spatial audio rendering system converts the audio object signal and target sound field parameters into multiple speaker drive signals, thereby forming a target gamma rhythmic sound field.

[0075] In another implementation, the system can realize a spatial sound field through WFS wave field synthesis. The basic gamma rhythm auditory stimulus signal can be used as a virtual sound source signal. The system generates a corresponding loudspeaker driving signal based on the target virtual sound source position, sound field propagation direction, spatial phase parameters, and loudspeaker array geometry, so that a gamma rhythm sound field with a preset spatial phase relationship is formed in the area where the target object is located.

[0076] The above-described spatial sound field implementation methods can be used individually or in combination. This invention is not limited to a specific audio transmission protocol, a specific number of speakers, or a specific spatial audio rendering algorithm. As long as an auditory stimulus sound field with a preset gamma phase relationship can be formed according to the spatial phase encoding parameters, it can be used as an implementation method of this invention.

[0077] In other embodiments, the present invention is not limited to gamma rhythmic auditory stimulation around 40Hz. For other target neural rhythmic stimuli, such as delta rhythms, theta rhythms, alpha rhythms, beta rhythms, or other gamma rhythms, the system can also calculate the corresponding stimulation period T according to the target stimulation frequency, and generate phase offset parameters, time offset parameters, gain parameters, and spatial weight parameters between multiple output units based on the stimulation period T, thereby forming a target neural rhythmic sound field with a preset spatial phase relationship. The main difference between the above embodiments and the gamma rhythmic sound field around 40Hz is the target stimulation frequency and its corresponding period T; the spatial phase encoding, output unit mapping, and spatial sound field generation methods can adopt the same or similar technical processes.

[0078] Example 11: Three-dimensional spatial phase coding mode of spherical array like Figure 9 As shown, in this embodiment, the multiple output units can be arranged as a spherical array, a hemispherical array, a near-spherical array, a multi-layered ring array, or other three-dimensional spatial distribution arrays. The output units can be physical speaker channels, or audio objects, virtual sound sources, or sound field control units in a spatial audio rendering system. Based on the azimuth, pitch, height levels, spatial partitions, or spherical path positions of each output unit relative to the center position of the target object, the system generates corresponding phase offset parameters φi, time offset parameters τi, gain parameters gi, and spatial weight parameters wi, thereby forming a three-dimensional spatial phase-encoded target neural rhythm sound field.

[0079] In one implementation, such as Figure 9 As shown in (a), the system employs a spherical layered phase rule. Multiple output units can be divided into upper, middle, and lower layers according to height or pitch angle. The system can configure the upper layer output unit group as the first target neural rhythm phase, the middle layer output unit group as the second target neural rhythm phase, and the lower layer output unit group as the third target neural rhythm phase. For example, under a 40Hz target rhythm, with a stimulation cycle T of 25ms, the system can configure the upper, middle, and lower layers as target neural rhythm phases of 0°, 120°, and 240°, respectively, thereby forming a layered phase structure in the vertical direction. The system can also set a preset phase difference between the upper and lower layers within the range of 0° to 180° to form a spatial rhythmic relationship in the vertical direction.

[0080] In another implementation, such as Figure 9As shown in (b), the system employs a polar scanning rule. The output unit located above the target object first outputs the target neural rhythm stimulation signal, followed by the output units located in the upper, middle, and lower rings, which sequentially output the target neural rhythm stimulation signal according to a preset time offset order, thus forming a spatial rhythmic sound field from top to bottom. The system can also reverse the time offset order, making the spatial rhythmic sound field appear to move from bottom to top. The aforementioned time offset parameter τi can be calculated from the phase offset parameter φi and the target stimulation period T.

[0081] In yet another implementation, such as Figure 9 As shown in (c), the system employs a spherical rotation or spiral phase rule. Multiple output units can be ordered according to a spherical path, which can be an equatorial path, a meridian path, an oblique spherical path, a spiral ascending path, or a spiral descending path. The system sequentially configures the target neural rhythm phase along the spherical path in an increasing or decreasing manner, so that the target neural rhythm sound field is in a progressive or rotating state along the spherical path. For example, for a multi-layered spherical output unit surrounding a target object, the system can configure the phase offset parameters in a spiral order of "lower layer front—middle layer side—upper layer rear—top region" to form a three-dimensional spirally progressive spatial rhythmic sound field.

[0082] In another implementation, the system employs radial convergence or divergence phase rules. Based on the spatial distribution of the output units relative to the center of the target object, the system configures different phase offset parameters and spatial weight parameters, causing the spatial rhythmic sound field to either converge toward the center region of the target object or diverge outwards from the center region. The radial convergence or divergence is not limited to the physical focusing of actual sound energy, but rather refers to the progressive relationship of the target neural rhythmic stimulation signal in terms of spatial phase, temporal offset, and spatial weight.

[0083] In yet another implementation, such as Figure 9 As shown in (d), the system employs a spherical symmetry grouping phase rule. The system can divide a spherical, hemispherical, or approximately spherical array into multiple spatial partitions, such as the upper front, lower front, upper back, lower back, upper left, upper right, lower left, and lower right partitions. Different spatial partitions can be configured with different target neural rhythm phase parameters, gain parameters, or spatial weight parameters. For example, the upper front and lower back partitions can be set to be in phase, and the upper left and lower right partitions can be set to a preset phase difference, thereby forming a spatial rhythmic sound field with a three-dimensional symmetry relationship.

[0084] In the above embodiments, the target neural rhythm can be a gamma rhythm around 40Hz, or other target neural rhythms. The system can select the target spatial phase distribution rule based on the EEG response indicators of the target object under different three-dimensional spatial phase encoding modes; it can also update the phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi based on the real-time EEG response signal during stimulation.

[0085] Through this embodiment, the present invention is not only applicable to planar surround output unit arrangements, but also to spherical, hemispherical, multi-layered or other three-dimensional spatial output unit arrangements, thereby forming a three-dimensional spatial phase-encoded target neural rhythm auditory stimulation sound field.

[0086] This invention proposes a method and system for generating a 40Hz auditory stimulus sound field based on spatial phase encoding of individual neural responses. Instead of simply playing a fixed 40Hz sound, this method determines an individualized gamma stimulation frequency fγ based on the target subject's EEG response, and maps the basic gamma rhythmic auditory stimulation signal into a multi-output unit stimulation signal with a spatial phase structure based on the gamma stimulation period T.

[0087] This invention encodes the phase relationship of the target neural rhythm between different output units using phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi, enabling auditory stimuli near 40Hz to form a rhythmic sound field with a preset spatial phase relationship. This sound field can be formed either directly from a physical multi-speaker array or converted into multiple speaker drive signals using a wave field synthesis system, object audio rendering system, or array sound field synthesis system.

[0088] This invention can realize planar or circumferential spatial phase coding modes such as in-phase distribution, grouped phase difference, linear progression, circular progression, scanning phase, and dynamically updated phase. It can also realize three-dimensional spatial phase coding modes such as spherical layering, epitropic scanning, spherical rotation or spiral, radial convergence or divergence, and spherical symmetric grouping. Among them, radial convergence or divergence is not limited to the physical focusing of actual acoustic energy, but refers to the progressive relationship of the target neural rhythm stimulation signal in terms of spatial phase, temporal offset, and spatial weight.

[0089] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the invention, based on the technical solution and concept of the invention, should be covered within the scope of protection of the invention.

Claims

1. A method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding, characterized in that, Includes the following steps: S1, output one or more auditory stimulation signals of gamma candidate frequencies to the target object, and acquire the corresponding EEG response signal of the target object; S2, determine the individualized gamma stimulation frequency based on the EEG response signal, wherein the individualized gamma stimulation frequency is in the range of 35Hz to 45Hz; S3, calculate the corresponding gamma stimulation period T based on the individualized gamma stimulation frequency; S4, Generate a basic gamma rhythmic auditory stimulus signal based on the individualized gamma stimulus frequency; S5, based on the target space phase distribution rule, determine the phase shift parameter φi of multiple output units within the same gamma stimulation period T, and calculate the corresponding time shift parameter τi based on the phase shift parameter φi, where: τi = (φi / 360°) * T; S6. Based on the basic gamma rhythm auditory stimulation signal and the phase offset parameter φi, time offset parameter τi, gain parameter gi and spatial weight parameter wi corresponding to each output unit, generate a spatial phase encoded gamma stimulation signal. S7, the spatial phase-encoded gamma stimulus signal is output to multiple speaker channels, or output to a spatial audio rendering system and converted into multiple speaker driving signals to form a 40Hz gamma rhythmic sound field with a preset spatial phase relationship in the sound field area where the target object is located. The target space phase distribution rules include one or more of the following: in-phase distribution rules, grouped phase difference rules, linear progressive phase rules, ring progressive phase rules, scanning phase rules, spherical layered phase rules, spherical rotation phase rules, radial convergence or divergence phase rules, spherical symmetric grouped phase rules, or dynamically updated phase rules. Under the in-phase distribution rule, the target neural rhythms corresponding to multiple output units have the same or essentially the same phase. Under the grouping phase difference rule, there is a target neural rhythm phase difference between different output unit groups in the range of 0° to 180°; Under the linear progressive phase rule, multiple output units are configured with target neural rhythm phases that increase or decrease sequentially in a straight line direction, an arc direction, or a preset spatial arrangement order. Under the aforementioned ring-progressive phase rule, multiple output units arranged around the target object are configured with target neural rhythm phases that increase or decrease sequentially in a ring-space order. Under the scanning phase rule, the output units located in different spatial directions of the target object output the target nerve rhythm stimulation signal in a preset delay sequence to form a spatial rhythmic sound field moving along the preset direction; Under the spherical layered phase rule, there is a preset target neural rhythm phase difference between output unit groups located in different height layers or different pitch angle ranges; Under the spherical rotation phase rule, multiple output units are configured with sequentially increasing or decreasing target neural rhythm phases according to the spatial arrangement order corresponding to the spherical path, so as to form a spatial rhythmic sound field that progresses or rotates along the spherical path. Under the radial convergence or divergence phase rule, multiple output units are configured with phase offset parameters and spatial weight parameters according to their spatial distribution relationship relative to the center position of the target object, so as to form a spatial rhythmic sound field that converges towards the center region of the target object or diverges outward from the center region of the target object. Under the spherical symmetry grouping phase rule, multiple output units are grouped according to their spatial partitions in a spherical, hemispherical, or approximately spherical array, with different spatial partitions corresponding to different target neural rhythm phase parameters; Under the dynamic phase update rule, at least some of the output units' corresponding phase offset parameters φi, time offset parameters τi, gain parameters gi, or spatial weight parameters wi are updated as time, target spatial path, or EEG response indicators change.

2. The method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding as described in claim 1, characterized in that, The one or more gamma candidate frequencies include multiple frequency points in the range of 35Hz to 45Hz, and the multiple frequency points include one or more of 38Hz, 39Hz, 40Hz, 41Hz and 42Hz; The EEG response signal is used to calculate one or more of the following indicators: gamma power gain, phase lock value, auditory steady-state response signal-to-noise ratio, brain region coherence, and left and right hemisphere synchronicity, and to determine the individualized gamma stimulation frequency based on the one or more indicators.

3. The method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding as described in claim 1, characterized in that, The basic gamma rhythm auditory stimulus signal includes one or more of the following: short-tone pulse sequence, amplitude-modulated sound, narrowband noise-modulated sound, broadband noise-modulated sound, or composite carrier-modulated sound. The short-tone pulse sequence is formed by repeatedly outputting a carrier signal according to the individualized gamma stimulation frequency. The frequency range of the carrier signal is 500Hz to 8000Hz, the width of a single pulse is 0.5ms to 20ms, and the envelope of a single pulse includes one or more of the following: rectangular window, Hann window, Gaussian window, exponential decay window, sine half-wave window, or custom smooth envelope.

4. The method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding as described in claim 1, characterized in that, The output unit includes one or more of the following: physical speaker channel, audio object in spatial audio rendering system, virtual sound source or sound field control unit; The spatial phase-encoded gamma stimulus signal includes a speaker channel signal corresponding to a physical speaker channel, or includes an audio object signal, a virtual sound source signal, or a sound field control signal for a spatial audio rendering system. The 40Hz gamma rhythmic sound field is formed directly by a physical multi-speaker array, or by rendering the audio object signal, virtual sound source signal, or sound field control signal into multiple speaker drive signals through a wave field synthesis system, object audio rendering system, or array sound field synthesis system.

5. The method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding as described in claim 1, characterized in that, The spatial phase-encoded gamma stimulus signal is output through a digital audio network, a multi-channel sound card, a multi-channel digital audio processor, or a multi-channel power amplifier system. The digital audio network includes one or more of Dante, AES67, RAVENNA, AVB, MADI, USB Audio, and Thunderbolt Audio.

6. The method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding as described in claim 1, characterized in that, The target spatial phase distribution rule is determined based on the EEG response index of the target object under different spatial phase distribution rules, or by adjusting one or more of the phase offset parameter φi, time offset parameter τi, gain parameter gi, and spatial weight parameter wi during stimulation based on the real-time EEG response signal.

7. The method for generating a 40Hz auditory stimulus sound field based on spatial phase encoding as described in claim 1, characterized in that, The spatial phase encoding method is also applicable to auditory stimuli of various target neural rhythms, including delta rhythms, theta rhythms, alpha rhythms, or beta rhythms. The system calculates the stimulation period T based on the target stimulation frequency corresponding to the target neural rhythm, and determines the phase offset parameter φi and time offset parameter τi of multiple output units according to the stimulation period T.

8. A 40Hz auditory stimulus sound field generation system based on spatial phase encoding, characterized in that, The method for generating an auditory stimulus sound field as described in any one of claims 1-7 includes: The EEG response acquisition module is used to acquire the EEG response signals of the target object at one or more gamma candidate frequencies; The individualized gamma frequency determination module is used to determine the individualized gamma stimulation frequency based on the EEG response signal and calculate the corresponding gamma stimulation period T. The basic stimulus signal generation module is used to generate a basic gamma rhythmic auditory stimulus signal based on the individualized gamma stimulus frequency. The spatial phase encoding module is used to determine the phase offset parameter φi, time offset parameter τi, gain parameter gi and spatial weight parameter wi of multiple output units within the same gamma stimulation period T, according to the target spatial phase distribution rules. The stimulation signal generation module is used to generate a spatial phase-coded gamma stimulation signal based on the basic gamma rhythm auditory stimulation signal and the phase offset parameter φi, time offset parameter τi, gain parameter gi and spatial weight parameter wi corresponding to each output unit. The sound field output module is used to output the spatial phase-encoded gamma stimulus signal to multiple speaker channels, or to output it to a spatial audio rendering system and convert it into multiple speaker drive signals to form a gamma rhythmic sound field around 40Hz.

9. The 40Hz auditory stimulus sound field generation system based on spatial phase encoding as described in claim 8, characterized in that, The spatial phase encoding module is used to generate spatial phase encoding parameters corresponding to in-phase distribution rules, grouped phase difference rules, linear progressive phase rules, ring progressive phase rules, scanning phase rules, spherical layered phase rules, spherical rotation phase rules, radial convergence or divergence phase rules, spherical symmetric grouped phase rules, or dynamically updated phase rules. The sound field output module includes a physical multi-speaker array output module, or a spatial audio rendering module; the spatial audio rendering module is used to convert audio object signals, virtual sound source signals, or sound field control signals into multiple speaker driving signals to form a spatialized gamma rhythmic sound field.

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