Method for measuring characteristics of nerves in terahertz wave band

Abstract

The invention provides a method for measuring characteristics of a nerve in a terahertz wave band. The method comprises the following steps: extracting the nerve of an experimental organism and preparing the nerve into a nerve sample with the thickness of 1-500nm; scanning and detecting a nerve sample point by point by using a terahertz near-field imaging system based on a scattering type scanning near-field optical microscope to obtain atomic force microscope height information and terahertz spectrum information; extracting terahertz feature information in the terahertz spectrum information, and reconstructing a terahertz image by using the terahertz feature information to obtain a reconstructed image; according to the actual structure of the nerve sample, determining a corresponding structure in the reconstructed image and extracting terahertz data of the corresponding structure; and calculating the refractive index optical parameter of the corresponding structure in the terahertz wave band to obtain the characteristics of the nerve sample in the terahertz wave band. According to the invention, the characteristics of the nerve in the terahertz wave band can be obtained, and the propagation rule of the neural signal in the neurons with different structures is disclosed, so that the essential mechanism of neural signal transmission is deeply explored.

Description

Technical Field

[0001] The present invention relates to the technical field of neural signal measurement, and in particular to a method for measuring neural characteristics in the terahertz band. Background Art

[0002] The nervous system is an important control center in the body, mainly responsible for transmitting body information, as well as coordinating and regulating various physiological activities. Neurons are the basic functional units of the nervous system, which transmit and process information by transmitting nerve signals. The structure of neurons plays a decisive role in the transmission of nerve signals. Compared with unmyelinated neurons, myelinated neurons can transmit nerve signals faster on the axon through saltatory conduction, thereby improving the conduction speed and efficiency of nerve signals.

[0003] The process of neural signal transmission is essentially an electromagnetic radiation phenomenon, which is in the broad terahertz band. Studies have shown that neural signal transmission involves multiple complex biophysical processes such as the opening and closing of ion channels, changes in transmembrane potential, and changes in the internal and external environment of neurons. These processes are closely related to the physical structure of neurons, including the refractive index and size of axons and myelin sheaths. Therefore, obtaining the characteristics of neurons in the terahertz band will help reveal the propagation laws of neural signals in neurons with different structures, thereby further exploring the essential mechanism of neural signal transmission. However, the precise transmission mechanism of neural signals inside neurons still lacks in-depth understanding. At present, there is an urgent need for a method to measure the characteristics of nerves in the terahertz band. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for measuring the characteristics of nerves in the terahertz band, which can obtain the characteristics of nerves in the terahertz band, reveal the propagation laws of nerve signals in neurons with different structures, and thus deeply explore the essential mechanism of nerve signal transmission.

[0005] To achieve the above object, the present invention provides the following solution: a method for measuring the characteristics of nerves in the terahertz band, comprising the following steps:

[0006] Extracting nerves from the experimental organism and fixing the nerves, cutting the nerves into ultrathin slices with a thickness of 1-500 nm using a mechanical push slicer, and transferring the ultrathin slices to a substrate to obtain nerve samples;

[0007] Using a terahertz near-field imaging system based on a scattering scanning near-field optical microscope to scan and detect the nerve sample point by point, and obtaining atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the nerve sample;

[0008] Extracting corresponding characteristic information from the terahertz spectrum information to obtain terahertz characteristic information, and reconstructing a terahertz image of the neural sample using the terahertz characteristic information to obtain a reconstructed image;

[0009] According to the actual structure of the neural sample, determining the corresponding structure in the reconstructed image and extracting terahertz data of the corresponding structure;

[0010] The terahertz data of the corresponding structure is used to calculate the refractive index optical parameters of the corresponding structure in the terahertz band, and the characteristics of the neural sample in the terahertz band are obtained.

[0011] Optionally, the substrate is selected to have a sub-nanometer flatness, and the substrate material is selected to have a material with high terahertz band reflection capability, and the substrate material includes gold, platinum, highly oriented thermal cracked graphite or graphene.

[0012] Optionally, the terahertz near-field imaging system based on the scattering scanning near-field optical microscope includes a terahertz source, a terahertz detector, a nanoprobe, a scanning imaging module and a control and analysis module;

[0013] The terahertz source is used to generate terahertz waves, and the terahertz source includes a free electron laser, a gas laser terahertz source, a quantum cascade laser terahertz source, a photoconductive antenna, an optical rectifier and a difference frequency device;

[0014] The terahertz detector is used to detect the terahertz wave, and the terahertz detector includes a Gega detector, a Schottky barrier diode mixer, a terahertz quantum well detector and a photoconductive antenna;

[0015] The nanoprobe is used to obtain the atomic force microscope height information of the nerve sample and modulate the near-field terahertz signal. When the terahertz light is irradiated on the end of the nanoprobe, the tip of the nanoprobe generates a locally enhanced near-field terahertz electric field. The nerve sample generates a scattered terahertz signal through the near-field terahertz electric field, and the scattered terahertz signal is received by the terahertz detector.

[0016] The scanning imaging module is used to control the nanometer-level displacement scanning of the neural sample to achieve high-resolution imaging;

[0017] The control and analysis module is used to control the terahertz near-field imaging system, process the scattered terahertz signal and perform data analysis.

[0018] Optionally, a terahertz near-field imaging system based on a scattering scanning near-field optical microscope is used to scan and detect the nerve sample point by point to obtain atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the nerve sample, including:

[0019] Placing the neural sample on the sample stage of the terahertz near-field imaging system, and positioning the neural sample using an optical microscope to obtain a target scanning area;

[0020] Utilizing the nanoprobe to align with the target scanning area, starting high-resolution point-by-point scanning detection, and obtaining atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the nerve sample;

[0021] The atomic force microscope height information is the surface morphology information of the nerve sample, and the terahertz spectrum information includes the terahertz time-domain spectrum, the peak value or single-sided peak height of the terahertz time-domain spectrum, and the amplitude and phase of the frequency-domain spectrum.

[0022] Optionally, extracting corresponding characteristic information from the terahertz spectrum information to obtain terahertz characteristic information, and reconstructing a terahertz image of the neural sample using the terahertz characteristic information to obtain a reconstructed image, comprises:

[0023] Analyze the terahertz spectrum information of each point in the neural sample, and extract the characteristic information corresponding to each point to obtain terahertz characteristic information; the terahertz characteristic information includes the maximum electric field change value, the phase change, the electric field intensity value at different frequencies, and the terahertz characteristic information obtained by reducing the dimensionality of the terahertz spectrum high-dimensional data by principal component analysis;

[0024] The terahertz characteristic information is set as the attribute of the pixel point, the terahertz image of the neural sample is reconstructed according to the attribute of the pixel point, and the terahertz image is smoothed, denoised, deconvolved and segmented to obtain a reconstructed image;

[0025] The reconstructed image is compared with the actual structure of the neural sample, the positions of different structures in the reconstructed image are determined, and the corresponding structure is obtained.

[0026] Optionally, using the terahertz data of the corresponding structure to calculate the refractive index optical parameters of the corresponding structure in the terahertz band to obtain the characteristics of the neural sample in the terahertz band includes:

[0027] Acquire the actual height of the corresponding structure based on the atomic force microscope height information, and acquire the spectrum of the nanoprobe at the actual height when there is no sample in the terahertz near-field imaging system as reference data;

[0028] Normalizing the electric field strengths of the nerve sample and the reference data to obtain a ratio value, and using the ratio value to calculate an effective near-field reflection coefficient;

[0029] The refractive index optical parameter is calculated using the actual height and the effective near-field reflection coefficient; the calculation formula of the refractive index optical parameter is:

[0030]

[0031] Among them, n sam is the refractive index optical parameter, is the effective near-field reflection coefficient, h is the actual height of the corresponding structure, and a is the effective charge height above the apex of the nanoprobe tip.

[0032] The invention discloses the following technical effects by providing a method for measuring the characteristics of nerves in the terahertz band:

[0033] 1. The present invention can break through the diffraction limit and realize nanoscale spatial distribution terahertz imaging of neural samples by utilizing the terahertz near-field imaging system of the scattering scanning near-field optical microscope, which is crucial for studying the microstructure and complex spatial distribution of neural samples.

[0034] 2. The present invention can accurately obtain the refractive index of the neural sample in the terahertz band. By measuring the refractive index, the characteristics of the neural sample in the terahertz band can be inferred. This is crucial for understanding the electrical properties and signal conduction mechanisms of neurons. By obtaining the characteristics of the terahertz band, the relationship between the structure of neurons and their functions can be studied. At the same time, nerves may show different refractive index characteristics under pathological conditions (such as neurodegenerative diseases). Refractive index measurement can assist in the diagnosis of neural diseases and fully understand the pathogenesis of the disease.

[0035] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 A flow chart of a method provided by an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a terahertz near-field imaging system provided by an embodiment of the present invention;

[0039] Figure 3 A scanning electron microscope image of a nerve sample provided by an embodiment of the present invention;

[0040] Figure 4 Atomic force microscope image of a neural sample provided by an embodiment of the present invention;

[0041] Figure 5 Terahertz reconstruction image of a neural sample provided by an embodiment of the present invention

[0042] Figure 6 A schematic diagram of the terahertz spectrum of an axon and myelin sheath provided by an embodiment of the present invention;

[0043] Figure 7 A refractive index distribution diagram of axons and myelin sheaths in the terahertz band provided by an embodiment of the present invention;

[0044] Explanation of the accompanying drawings: 1. Terahertz source; 2. Parabolic reflector; 3. Nanoprobe; 4. High-resolution scanning imaging module; 5. Terahertz detector; 6. Control and analysis module. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Example

[0048] 1. If Figure 1-7 As shown, the present invention provides a method for measuring the characteristics of nerves in the terahertz band, comprising the following steps:

[0049] 1. Sample preparation

[0050] The nerves of the experimental organism are extracted and fixed, and then the nerves are cut into ultra-thin slices with a thickness of 1-500 nm using a mechanical push-type slicer, and the ultra-thin slices are transferred to a substrate to obtain nerve samples.

[0051] The substrate is selected to have a sub-nanometer flatness, and the substrate material is selected to have a material with high terahertz band reflection ability, and the substrate material includes gold Au, platinum Pt, highly oriented thermal cracked graphite (HOPG) or graphene.

[0052] 2. Choose a high-resolution terahertz spectroscopy system

[0053] like Figure 2As shown, the terahertz near-field imaging system based on the scattering scanning near-field optical microscope includes a terahertz source, a terahertz detector, a nanoprobe, a scanning imaging module and a control and analysis module.

[0054] The terahertz source is used to generate terahertz waves, and the terahertz source includes a free electron laser, a gas laser terahertz source, a quantum cascade laser terahertz source, a photoconductive antenna, an optical rectifier and a difference frequency device;

[0055] The terahertz detector is used to detect the terahertz wave, and the terahertz detector includes a Gega detector, a Schottky barrier diode mixer, a terahertz quantum well detector and a photoconductive antenna;

[0056] The nanoprobe is used to obtain the atomic force microscope height information of the nerve sample and modulate the near-field terahertz signal. When the terahertz light is irradiated on the end of the nanoprobe, the tip of the nanoprobe generates a locally enhanced near-field terahertz electric field. The nerve sample generates a scattered terahertz signal through the near-field terahertz electric field, and the scattered terahertz signal is received by the terahertz detector.

[0057] The scanning imaging module is used to control the nanometer-level displacement scanning of the neural sample to achieve high-resolution imaging;

[0058] The control and analysis module is used to control the terahertz near-field imaging system, process the scattered terahertz signal and perform data analysis.

[0059] 3. Terahertz high-resolution scanning

[0060] like Figure 3-4 As shown, a terahertz near-field imaging system based on a scattering scanning near-field optical microscope is used to scan and detect the neural sample point by point to obtain atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the neural sample. Specifically, it includes:

[0061] Placing the neural sample on the sample stage of the terahertz near-field imaging system, and positioning the neural sample using an optical microscope to obtain a target scanning area;

[0062] The nanoprobe is aligned with the target scanning area, and high-resolution point-by-point scanning detection is started to obtain the atomic force microscope height information related to the spatial distribution of the nerve sample (such as Figure 4 ) and terahertz spectroscopy information;

[0063] The atomic force microscope height information is the surface morphology information of the nerve sample, and the terahertz spectrum information includes the terahertz time-domain spectrum, the peak value or single-sided peak height of the terahertz time-domain spectrum, and the amplitude and phase of the frequency-domain spectrum.

[0064] 4. Terahertz image reconstruction

[0065] like Figure 5 As shown, extracting corresponding characteristic information from the terahertz spectrum information to obtain terahertz characteristic information, and reconstructing the terahertz image of the neural sample using the terahertz characteristic information to obtain a reconstructed image; comprising:

[0066] Analyze the terahertz spectrum information of each point in the neural sample, and extract the characteristic information corresponding to each point to obtain terahertz characteristic information; the terahertz characteristic information includes the maximum electric field change value, the phase change, the electric field intensity value at different frequencies, and the terahertz characteristic information obtained by reducing the dimensionality of the terahertz spectrum high-dimensional data by principal component analysis;

[0067] The terahertz characteristic information is set as the attribute of the pixel point, the terahertz image of the neural sample is reconstructed according to the attribute of the pixel point, and the terahertz image is smoothed, denoised, deconvolved and segmented to obtain a reconstructed image;

[0068] The reconstructed image is compared with the actual structure of the nerve sample, and the positions of different structures (such as axons and myelin sheaths) in the reconstructed image are determined to obtain the corresponding structure.

[0069] 5. According to the actual structure of the neural sample, determine the positions of different structures in the reconstructed image (ie, corresponding structures) and extract the terahertz data of the corresponding structures.

[0070] 6. Terahertz characteristics analysis

[0071] 6.1 As Figure 6-7 As shown, the terahertz data of the corresponding structure is used to calculate the refractive index optical parameters of the corresponding structure in the terahertz band, and the characteristics of the neural sample in the terahertz band are obtained. Specifically including:

[0072] Acquire the actual height of the corresponding structure based on the atomic force microscope height information, and acquire the spectrum of the nanoprobe at the actual height when there is no sample in the terahertz near-field imaging system as reference data;

[0073] The electric field strengths of the nerve sample and the reference data are normalized to obtain a ratio value, and the effective near-field reflection coefficient is calculated using the ratio value.

[0074] The refractive index optical parameter is calculated using the actual height and the effective near-field reflection coefficient; the calculation formula of the refractive index optical parameter is:

[0075]

[0076] Among them, nsam is the refractive index optical parameter, is the effective near-field reflection coefficient, h is the actual height of the corresponding structure, and a is the effective charge height above the apex of the nanoprobe tip.

[0077] 6.2 The calculation formula of the refractive index optical parameter is derived by the following formula:

[0078] E re ∝(1+r) 2 α eff E ir (1)

[0079] Among them, E re and E ir are the incident and received terahertz signals, respectively, (1+r) 2 is the far-field terahertz reflection term, α eff is the effective polarizability of the nanoprobe tip-sample system.

[0080]

[0081]

[0082] Among them, f w0 (D) and f w1 (D) is a parameter related to the tip shape, tip-sample distance, and the position of the induced charge at the tip; g represents the proportion of the near-field induced charge in the tip, R is the tip radius, D is the tip vibration curve, and L is the half-length of the probe tip; w0 and w1 are the distances between the position of the polarization charge induced by the incident terahertz electric field at the tip and the apex of the tip end when there is no and with sample action, respectively.

[0083]

[0084] S n ∝|F n | (5)

[0085]

[0086] Among them, α eff-n represents the n-order effective polarizability, n is an integer, i represents the imaginary part, F n and φ n are the Fourier transform coefficient and phase of the n-order component respectively; S n is the n-order signal intensity of the sample. For the time domain spectrum, the frequency-dependent electric field amplitude A(f) and phase can be calculated by Fourier transform.

[0087]

[0088]

[0089] z a =D+a (9)

[0090] in, is the effective near-field reflection coefficient, which is determined by the terahertz wave quantity q; z a It represents the distance between the reflected electric field position on the sample surface and the sample surface, a is the effective charge height above the apex of the needle tip, and h is the actual thickness of the sample.

[0091]

[0092]

[0093]

[0094] Among them, β air-sam is the reflection coefficient of the air-sample interface; β sam-sub is the reflection coefficient of the sample-substrate interface, ε sub represents the substrate dielectric constant, ε sam represents the sample dielectric constant, n sam Refractive index of the sample.

[0095] The above formulas (1)-(12) can be simplified to the following process:

[0096] First, the actual height h of the corresponding structure is obtained based on the height information of the atomic force microscope. Then, the spectrum of the probe at this height when there is no sample in the system is obtained as reference data. The electric field strength of the sample and the reference data are normalized to obtain their ratio. Through this ratio, combined with formulas (1)-(5), the effective near-field reflection coefficient is obtained: For the time domain spectrum, the effective near-field reflection coefficient at different frequencies can be obtained by formula (6): For thin neural samples, q is approximately equal to 2z a , let z a =a, the sample refractive index can be calculated by formula (1)-(12)

[0097] 2. The present invention uses mouse nerve samples as an example to perform terahertz detection:

[0098] 1. Select a high-resolution terahertz spectroscopy system: A scattering terahertz near-field imaging system based on a terahertz source and detector using a photoconductive antenna was used to detect mouse nerve samples.

[0099] 2. Sample preparation: The mouse sciatic nerve was extracted and fixed into ultra-thin slices with a mechanical push slicer. The slices were then transferred to a flat gold-plated substrate for terahertz near-field scanning testing.

[0100] 3. Terahertz high-resolution scanning detection: Place the prepared neural sample on the sample stage of the scattering terahertz near-field system, use the optical microscope integrated in the terahertz system to position the sample, align the nanoprobe with the target scanning area, and then use the terahertz near-field imaging system to perform high-resolution point-by-point scanning detection, so as to obtain the atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the sample.

[0101] 4. Terahertz image reconstruction: By analyzing the terahertz spectrum information of each point of the sample, the corresponding terahertz maximum electric field change value is extracted and used as the attribute of the pixel point to construct the terahertz image of the sample (refer to Figure 5 ), and perform smoothing, denoising and image segmentation on the image to improve the clarity and resolution of the image;

[0102] 5. By comparing the terahertz image and scanning electron microscope image of the sample (reference Figure 3 ), determine the location of axons and myelin sheaths in the image; then extract terahertz spectral data of these structures (ref. Figure 6 ), and calculate the refractive index optical parameters of these structures in the terahertz band (reference Figure 7 )

[0103] Therefore, the present invention provides a method for measuring the characteristics of nerves in the terahertz band, which can obtain the characteristics of nerves in the terahertz band, reveal the propagation laws of nerve signals in neurons with different structures, and thus deeply explore the essential mechanism of nerve signal transmission.

[0104] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0105] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for measuring nerve characteristics in the terahertz band, characterized in that: The following steps are involved: Extracting nerves from the experimental organism and fixing the nerves, cutting the nerves into ultrathin slices with a thickness of 1-500 nm using a mechanical push slicer, and transferring the ultrathin slices to a substrate to obtain nerve samples; Using a terahertz near-field imaging system based on a scattering scanning near-field optical microscope to scan and detect the nerve sample point by point, and obtaining atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the nerve sample; Extracting corresponding characteristic information from the terahertz spectrum information to obtain terahertz characteristic information, and reconstructing a terahertz image of the neural sample using the terahertz characteristic information to obtain a reconstructed image; According to the actual structure of the neural sample, determining the corresponding structure in the reconstructed image and extracting terahertz data of the corresponding structure; The terahertz data of the corresponding structure is used to calculate the refractive index optical parameters of the corresponding structure in the terahertz band, and the characteristics of the neural sample in the terahertz band are obtained.

2. The method for measuring nerve characteristics in the terahertz band according to claim 1, characterized in that: The substrate is selected to have a sub-nanometer flatness, and the substrate material is selected to have a material with high terahertz band reflection ability, and the substrate material includes gold, platinum, highly oriented thermal cracking graphite or graphene.

3. The method for measuring nerve characteristics in the terahertz band according to claim 2, characterized in that: The terahertz near-field imaging system based on the scattering scanning near-field optical microscope includes a terahertz source, a terahertz detector, a nanoprobe, a scanning imaging module and a control and analysis module; The terahertz source is used to generate terahertz waves, and the terahertz source includes a free electron laser, a gas laser terahertz source, a quantum cascade laser terahertz source, a photoconductive antenna, an optical rectifier and a difference frequency device; The terahertz detector is used to detect the terahertz wave, and the terahertz detector includes a Gega detector, a Schottky barrier diode mixer, a terahertz quantum well detector and a photoconductive antenna; The nanoprobe is used to obtain the atomic force microscope height information of the nerve sample and modulate the near-field terahertz signal. When the terahertz light is irradiated on the end of the nanoprobe, the tip of the nanoprobe generates a locally enhanced near-field terahertz electric field. The nerve sample generates a scattered terahertz signal through the near-field terahertz electric field, and the scattered terahertz signal is received by the terahertz detector. The scanning imaging module is used to control the nanometer-level displacement scanning of the neural sample to achieve high-resolution imaging; The control and analysis module is used to control the terahertz near-field imaging system, process the scattered terahertz signal and perform data analysis.

4. The method for measuring nerve characteristics in the terahertz band according to claim 3, characterized in that: The neural sample is scanned point by point using a terahertz near-field imaging system based on a scattering scanning near-field optical microscope to obtain atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the neural sample, including: Placing the neural sample on the sample stage of the terahertz near-field imaging system, and positioning the neural sample using an optical microscope to obtain a target scanning area; Utilizing the nanoprobe to align with the target scanning area, starting high-resolution point-by-point scanning detection, and obtaining atomic force microscope height information and terahertz spectrum information related to the spatial distribution of the nerve sample; The atomic force microscope height information is the surface morphology information of the nerve sample, and the terahertz spectrum information includes the terahertz time-domain spectrum, the peak value or single-sided peak height of the terahertz time-domain spectrum, and the amplitude and phase of the frequency-domain spectrum.

5. The method for measuring nerve characteristics in the terahertz band according to claim 4, characterized in that: Extracting corresponding characteristic information from the terahertz spectrum information to obtain terahertz characteristic information, and reconstructing a terahertz image of the neural sample using the terahertz characteristic information to obtain a reconstructed image, including: Analyze the terahertz spectrum information of each point in the neural sample, and extract the characteristic information corresponding to each point to obtain terahertz characteristic information; the terahertz characteristic information includes the maximum electric field change value, the phase change, the electric field intensity value at different frequencies, and the terahertz characteristic information obtained by reducing the dimensionality of the terahertz spectrum high-dimensional data by principal component analysis; The terahertz characteristic information is set as the attribute of the pixel point, the terahertz image of the neural sample is reconstructed according to the attribute of the pixel point, and the terahertz image is smoothed, denoised, deconvolved and segmented to obtain a reconstructed image; The reconstructed image is compared with the actual structure of the neural sample, the positions of different structures in the reconstructed image are determined, and the corresponding structure is obtained.

6. The method for measuring nerve characteristics in the terahertz band according to claim 5, characterized in that: The terahertz data of the corresponding structure are used to calculate the refractive index optical parameters of the corresponding structure in the terahertz band, and the characteristics of the neural sample in the terahertz band are obtained, including: Acquire the actual height of the corresponding structure based on the atomic force microscope height information, and acquire the spectrum of the nanoprobe at the actual height when there is no sample in the terahertz near-field imaging system as reference data; Normalizing the electric field strengths of the nerve sample and the reference data to obtain a ratio value, and using the ratio value to calculate an effective near-field reflection coefficient; The refractive index optical parameter is calculated using the actual height and the effective near-field reflection coefficient; the calculation formula of the refractive index optical parameter is: Among them, n sam is the refractive index optical parameter, is the effective near-field reflection coefficient, h is the actual height of the corresponding structure, and a is the effective charge height above the apex of the nanoprobe tip.

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