Remote neural monitoring based on magnetic resonance in the Earth's magnetic field and biocorrelation

 

Synopsis

 

A theory is presented for remote neural monitoring based on magnetic resonance in the Earth’s magnetic field and biocorrelation. A combination of NMR/MRI and ESR is suggested in a scheme that integrates dynamic nuclear polarization (DNP) for transfer of polarization from the electrons to the protons. This scheme is equivalent to the technique of Proton Electron Double Resonance Imaging (PEDRI) or Overhauser Magnetic Resonance Imaging (OMRI). This would be used similarly to the emerging technique of magnetic resonance current density imaging (MRCDI) for brain magnetic activity quantification. The magnetic field of the brain introduces a perturbation in the static magnetic field and the total magnetic field is provided by their vectorial sum. The latter modifies the precession frequency of spins and thereby introduces a phase shift which is dependent on the strength of the given magnetic field at any instant. In this manner, the phase shifts modulate the magnetic resonance signal, whose measurement allows for the determination of the magnetic field of the brain at any instant, in a process that resembles magnetoencephalography based on magnetic resonance. 

 

The signal can either be read off the subject or from its immediate environment including with techniques of remote magnetometry e.g. Zeeman spectroscopy of magnetically sensitive emissions like those of atmospheric oxygen and LGS-technology for determination of atmospheric sodium precession frequency. Also quantum techniques and atom interferometry could be used for reading the magnetic field such as the Aharonov-Bohm effect (Aharonov-Bohm (AB) phase) for detection of electromagnetic potential.

 

It must be emphasized that resolution of signal acquisition can be low, if the signal is biocorrelated i.e. correlated to biological signals and cognitive models similarly to magnetic resonance fingerprinting. The existence of cognitive models with well-characterized main brain circuits minimizes the image acquisition requirements as the signal can easily be fitted to a predefined template.

 

According to this hypothesis, the magnetic field of the Earth is transformed into a gigantic magnetic resonance scanner. There is also the possibility to use the electric field gradient of the Earth's atmosphere.

 

In order to perform magnetic resonance in the Earth's magnetic field, conditions similar to those for ultra-low field at 100 times the Earth’s magnetic field could be used:

 

1. Circularly polarized electromagnetic radiation
2. specific pulse sequences (balanced Steady-State-Free-Precession (b-SSFP) sequences)  which dynamically refocus the spins after measurement
3. undersampling (sparse sampling) which implies that only the best, most representative features are sampled (and therefore noise is discarded by default)
4. magnetic resonance fingerprinting, which consists of identifying fingerprints via matching to a predefined dictionary of predicted signal evolutions using pattern recognition algorithms; this allows for multiparametric analyses similar to genomic or proteomic analyses.
5. theoretical frameworks for image reconstruction using multiple channel acquisition and parallel imaging i.e. different coils. 
6. parallelized computing which enables to address computationally demanding tasks.

 


 
There have been significant efforts of MRI and NMR in the Earth’s magnetic field, such as the development of the Terranova MRI scanner. It must be stressed that surface NMR in large scale is conducted in the Earth's magnetic field for groundwater and oil detection using cables connected to a power supply. Also well NMR logging is conducted in the Earth's magnetic field or low magnetic fields using for instance a probe for rock magnetization.


If we accepted that remote neural monitoring based on magnetic resonance could be conducted in the Earth’s magnetic field, then the magnetic resonance frequencies for the proton and the electron could be calculated by multiplying the gyromagnetic ratio of the proton (42.5781 MHz/T) or that of the electron (28.025 GHz/T) with the Earth’s magnetic field strength which for instance in central France is equal to 47 μT. Specifically:


Proton resonance frequency = 42.5781 MHz/T * 0,000047 T = 2,00 KHz
This frequency resides in the Ultra low frequency (ULF) range (300 Hz - 3 KHz).


Electron resonance frequency = 28.025 GHz/T * 0,000047 T = 1,32 MHz 
This frequency resides in the Medium frequency (MF) (300 KHz - 3 MHz) and in the radiofrequency range (20 kHz - 300 GHz) below the microwave frequency range.


In order to conduct proton and electron magnetic resonance in the Earth’s magnetic field, we would need to use the electromagnetic frequencies 2,00 KHz and 1,32 MHz respectively or their harmonics. It is also suggested that a pulse rate corresponding to the above values could have a similar result.

 

It is noted that low frequencies (1-100KHz) generate surface charges on the human body (surface charging) via electrostatic induction. This means that there will be free electrons, positive and negative ions on the body surface which could enhance the MR signal (e.g. ESR signal) Also frequencies below 14 MHz are considered as quasi-static for the human body and can provide a static field that intensifies the MR signal.

 

 
 

 

Detailed description

 

Introduction 

 

Brain and body electromagnetic activity represent an electric and magnetic flux of small intensity which is difficult to measure remotely. However, upon a certain excitation process and specifically spin excitation in the frame of magnetic resonance, it could be possible to generate a remotely measurable electric/magnetic flux. Neural monitoring techniques based on magnetic resonance that could be used for remote neural monitoring include functional magnetic resonance imaging (fMRI) using BOLD contrast for detection of brain activation and magnetic resonance current density imaging (MRCDI) which via quantification of brain magnetic fields would correspond to magnetoencephalography based on magnetic resonance.

 

 

 

Magnetic resonance imaging (MRI)

 

In magnetic resonance imaging, we use the spins of hydrogen nuclei or in other words the proton spins due to their abundance; they are found in water which constitutes 65% of body content. The subject is placed into the strong magnetic field of an MRI scanner which aligns its spins towards the direction of the magnetic field, thereby generating a longitudinal magnetization in this direction, conventionally on the z axis. When in a magnetic field (B) such as that of the scanner which has a stength of approximately 1 Tesla, the spins will precess or wobble around the direction of the magnetic field with a frequency termed Larmor frequency (ω) which is equal to the magnetic field strength multiplied by the gyromagnetic ratio of the proton (γ) which is equal to 42,57 MHz/T. Therefore, the spins will precess at a frequency ω of 42,57 MHz (ω = γ * Β => ω = 42,57 MHz/T * 1 T => ω = 42,57 MHz). 

 

If we apply an electromagnetic frequency equal to the Larmor frequency i.e. 42,57 MHz (radiofrequency, RF) magnetic resonance will occur. The spins will absorb the provided electromagnetic energy, will be excited and will be flipped. By applying the RF perpendicularly for an appropriate duration, the spins will be flipped in the xy plane and the longitudinal magnetization will be transformed to a transverse magnetization which will precess in the new plane under the effect of the RF. If we stop the RF, spins will start relaxing (relaxation) i.e. emitting the absorbed radiation and at the same time as interactions from the field of neighbouring spins and also collisions become prominent, they will stop being synchronized and they will start dephasing or practically "not being in phase", as for instance phase "lags" may be introduced in their precession motion. As a result of the decrease of the synchronized behavior of the spins, the transverse mangetization will be decreased. This process is termed T2 relaxation. The energy emitted constitutes the MRI signal termed FID (free induction decay) which is captured by a coil. Subsequently, the spins will start returning towards the z axis. This process is termed T1 relaxation. 

 

More details: http://www.information-book.com/science-tech-general/information-on-magnetic-resonance-mri/

 

 

 

Functional magnetic resonance (fMRI)

 

Functional magnetic resonance (fMRI) measures brain activitiy by detecting changes in blood oxygenation which is known as Blood Oxygenation Level Dependent (BOLD) contrast. This is achieved by the examination of the profile of the oxygen carrier in the blood, hemoglobin (Hb). Deoxygenated hemoglobin (dHb) is more magnetic (paramagnetic) than oxygenated hemoglobin (Hb), which is virtually resistant to magnetism (diamagnetic). As a result, oxygenated hemoglobin interferes less with magnetic resonance and leads to an increased MRI signal. This allows to establish a correlation between an increased MRI signal and brain activation.

 

More details: http://www.information-book.com/science-tech-general/fmri/

 

 

 

Magnetic resonance current density imaging (MRCDI)

 

An emerging technique termed magnetic resonance current density imaging (MRCDI) and the related technique termed magnetic resonance electrical impedance tomography (MREIT) allow quantification of the magnetic field of the brain following current injection in a procedure that could be similar to magnetoencephalography based on magnetic resonance. These studies are conducted with an interest in the effect of brain stimulation (tDCS/tACS).

 

Similarly to what was mentioned above, the subject is placed into the strong magnetic field of an MRI scanner which aligns its spins towards the direction of the magnetic field, thereby generating a longitudinal magnetization (Mz) in this direction, conventionally on the z axis. The magnetic field of the brain is considered to constitute a perturbation of the magnetic field of the scanner (and should be added vectorially to it). The total magnetic field is equal to the vectorial sum of the magnetic field of the scanner and that of the perturbation. As the strength of the latter is considered to be in the order of ppm while that of the scanner is approximately 1 T, it is proven that only the perturbation component in the z axis should be taken into account. The resultant magnetic field, referred to as ΔBz, will slightly change the precession frequency of the magnetization vector Mz, given that this frequency depends on the magnetic field strength and therefore it will change the phase i.e. it will introduce a phase shift. The change of the phase will modulate the measured MRI signal proportionally to ΔBz. By measuring the phase change, we can determine the induced ΔBz and quantify the magnetic field of the brain at any instant, thereby obtaining what would constitute a magnetoencephalograph representing the magnetic activity of the brain.


More details: http://www.information-book.com/science-tech-general/mrcdi-mreit/

 

 

 

Electron spin resonance (ESR)

 

Magnetic resonance imaging (MRI) is essentially “proton resonance imaging” as it uses the magnetic resonance of the hydrogen nucleus i.e. the proton. A similar technique termed electron spin resonance (ESR) or electron paramagnetic imaging (EPR) uses the magnetic resonance of the electron. 


It has been suggested by Holder D.S (19851987) that ESR could be most appropriate for the detection of brain electric activity. Holder is also cited in U.S. patent 4719425 https://www.google.com/patents/US4719425) for detection of brain activity with NMR and ESR. Due to the decreased abundance in biological systems of unpaired electrons (detected by the technique) and the short half-lives of related species such as free radicals, ESR is generally conducted with introduction of a paramagnetic substance which acts as a reporter. Also, given that the gyromagnetic ratio for the electron is 28 GHz/T, this means that for a scanner of 1 Tesla, the electromagnetic radiation required to achieve magnetic resonance is 28 GHz which is in the range of microwaves. This is problematic due to the fact that water, the main component of the human body, absorbs microwaves.

 

 

 

Combination of MRI and ESR: Proton Electron Double Resonance Imaging (PEDRI) or Overhauser Magnetic Resonance Imaging (OMRI) 

 

A powerful imaging application is represented by the combination of MRI and ESR which is known as Proton Electron Double Resonance Imaging (PEDRI) or Overhauser Magnetic Resonance Imaging (OMRI). The Overhauser effect is a prominent mechanism of dynamic nuclear polarization (DNP) (cf. hyperpolarization)  which consists of the transfer of the polarization of electrons to nuclei (including protons) resulting in the polarization of the latter. Practically, instead of irradiating the nuclei, one irradiates or excites the electrons and thereby mediates nuclei polarization. On a technical aspect, samples are irradiated at the resonance frequency of the electrons while the magnetic field strength is kept low and then the magnetic field is increased rapidly to obtain the nuclear magnetic resonance signal. To avoid tissue overheating by the ESR pulse, the technique field‐cycled PEDRI was developed. 

 

Patent US4719425A entitled “NMR imaging method and apparatus” presents a technique for measuring the electrical activity of the brain using NMR and ESR based as mentioned on “measuring the broadening of the width of NMR spectral lines”. Its principle appears to be similar to that presented for MRCDI. Quoting the patent, “a discharging neuron in the brain introduces an inhomogeneity in the magnetic field which reveals itself as a broadening of resonance lines which can be measured to determine the neuron discharge current flux”. The said inhomogeneity is equivalent to the perturbation mentioned in the MRCDI section. This leads to dephasing and thereby different precession frequencies resulting in spectroscopic line broadening. Also, the Fourier transform providing a Lorentzian (similar to the bell-curve distribution Gaussian distribution) due to different frequencies has an increased linewidth. By measuring the phase change by can determine the magnetic field of the brain.

 

 

 

The signal is read off the subject or from its immediate environement with established remote magnetometry techniques

 

The signal can either be read off the subject or from its immediate environment with techniques of remote magnetometry similar to those used for magnetic anomaly detection i.e. the perturbation of the Earth’s magnetic field due to a metallic object including, for example, mines or vessels/submarines. Also, some chemical species, like atmospheric oxygen, have magnetically sensitive spectroscopic lines (Zeeman effect) and therefore a change in the magnetic field strength will induce electronic transitions corresponding to a change in emission. This can be identified using remote magnetometry with Zeeman spectroscopy. 

 

More details:

http://www.information-book.com/science-tech-general/remote-magnetometry-zeeman-effect/

http://www.information-book.com/physics/faraday-effect-circular-dichroism/

 

Additionally, another atmospheric element, sodium, existing in abundance at 100 Km from the Earth’s surface, is used in remote magnetometry with the Laser-Guide-Star (LGS) technology. This technique consists of the measurement of the precession frequency of sodium in order to determine the Earth’s magnetic field. To this purpose a specific excitation is used which maximizes emission upon conditions of optical-magnetic resonance and can therefore be used to determine precession frequency. 

 

More details: http://www.information-book.com/science-tech-general/remote-magnetometry-lidar-laser-magnetometry/

 

Finally, the magnetic field change may be read with quantum techniques and atom interferometry using the Aharonov-Bohm effect (Aharonov-Bohm (AB) phase) for detection of electromagnetic potential.

 

More details:

http://www.information-book.com/physics/atom-interferometers/

http://www.information-book.com/physics/aharonov-bohm-effect-electromagnetic-potential-scalar-literature/

 

 

 

Magnetic resonance in the ultra-low field and the Earth’s magnetic field

 

Given that magnetic resonance is currently routinely conducted using scanners generating a magnetic field of at least 1 Tesla, i.e. 20.000 times the Earth’s magnetic field (25 to 65 μT) for spin polarization, the question that emerges is how it is possible to polarize the spins in a low magnetic field such as the Earth’s magnetic field.

 

There have been considerable advances in ultra-low field magnetic resonance (by definition below 10mT) at approximately 100 times the Earth’s magnetic field. A 6.4mT (100x Earth’s magn. field) commercial scanner by Hypefine Research currently under FDA-approval procedure is being tested at five teaching hospitals in the U.S. including those of Yale and Penn State University (ref.). It is noted that the scanner was inspired by work at the MGH - (ref.). 

 

Additionally, there have been significant efforts of MRI and NMR in the Earth’s magnetic field, such as the development of the Terranova MRI scanner (brochure, presentation). The system with certain modifications is used for the study "a practical and flexible implementation of 3D MRI in the Earth’s magnetic field" by Halse M.E. et al (2006) (pdf.) which images an object (red capsicum). A related study by Mohoric A. et al (2004) images similar objects.

 

It must be stressed that surface NMR in large scale is conducted in the Earth's magnetic field for groundwater and oil detection using cables connected to a power supply (ref.). Also well NMR logging is conducted in the Earth's magnetic field or low magnetic fields using for instance a probe for rock magnetization (ref.).

 

More details: http://www.information-book.com/science-tech-general/low-field-mri/

 

 

 

Pulse sequences for spin refocusing, undersampling, magnetic resonance fingerprinting, image reconstruction frameworks are used in ultra-low field MRI

 

As mentioned, the latest ultra-low field MRI scanner is based on work of researchers from the MGH. The study of Sarracanie M. et al 2015 by MGH researchers (also researchers affiliated with Harvard Medical School and Harvard Physics) who performed brain MRI in 6.5mT is indicative of what needs to be used to conduct MRI in low magnetic fields:

 

1. specific pulse sequences (balanced Steady-State-Free-Precession (b-SSFP)* sequences which dynamically refocus the spins after measurement

2. undersampling (sparse sampling) which implies that only the best, most representative features are sampled (and therefore noise is discarded by default)

3. magnetic resonance fingerprinting, which consists of identifying fingerprints via matching to a predefined dictionary of predicted signal evolutions using pattern recognition algorithms; this allows for multiparametric analyses similar to genomic or proteomic analyses.

4. theoretical frameworks for image reconstruction using multiple channel acquisition and parallel imaging i.e. different coils. 

5. parallelized computing which enables to address computationally demanding tasks.

 

 

 

Cognitive models with well-characterized main brain circuits facilitate magnetic resonance imaging.

 

It must be emphasized that the existence of cognitive models with well-characterized main brain circuits minimizes the image acquisition requirements as the signal can be easily fitted to a predefined template.

 


 

Circularly polarized electromagnetic radiation presents significant advantages

 

Additionally, strong spin manipulation (cf. polarization/excitation) can be conducted in ultra-low field MRI using circularly polarized electromagnetic radiation (Shim J.H. et al 2013). Circular polarization when compared to linear polarization reduces excitation power up to 50%, improves signal-to-noise ratio (√2) and reduces significantly artifact intensity Glover G.H. et al (1985), Schratter M. et al (1990)

It is noted that a circularly polarized field can be generated by creating a phase difference of 90° in the currents of two identical coils e.g. by adopting an orthogonal coil configuration.

 

 More details: http://www.information-book.com/science-tech-general/mri-circular-polarization/


 

 

Frequencies for proton and electron magnetic resonance in the Earth’s magnetic field

 

If we accepted that remote neural monitoring based on magnetic resonance could be conducted in the Earth’s magnetic field, then the magnetic resonance frequencies for the proton and the electron could be calculated by multiplying the gyromagnetic ratio of the proton (42.5781 MHz/T) or that of the electron (28.025 GHz/T) with the Earth’s magnetic field strength which for instance in central France is equal to 47 μT. Specifically:


 

Proton resonance frequency = 42.5781 MHz/T * 0,000047 T= 2,00 KHz

This frequency resides in the Ultra low frequency (ULF) range (300 Hz and 3 KHz).

 

Electron resonance frequency = 28.025 GHz/T * 0,000047 T= 1,32 MHz 

This frequency resides in the Medium frequency (MF) (300 KHz-3 MHz) and in the radiofrequency range (20 kHz - 300 GHz) below the microwave frequency range.

 

In order to conduct proton and electron magnetic resonance in the Earth’s magnetic field we would need to use the electromagnetic frequencies 2,00 KHz and 1,32 MHz respectively or their harmonics. It is also suggested that a pulse rate corresponding to the above values could have a similar result.

 

 

 

Low frequencies generate surface charges on the human body (surface charging) via electrostatic induction and could therefore enhance the MR signal

 

Frequencies in the range of 1 Hz to 100 KHz are considered to belong to the category of “Low Frequencies” according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Low-frequency electric fields, similarly to static fields, exert forces on a conductive body, which does not allow significant penetration of the electric field, thereby causing movements of electric charges on the body surface. This process is known as electrostatic induction (ref.). The surface will be charged, while the interior of the conductive body could be practically field-free. This means that there will be free electrons, positive and negative ions on the body surface which could be used for magnetic resonance, such as ESR for instance, in order to enhance the signal.

 

 

 

Frequencies below 14 MHz are considered as quasi-static for the human body and can provide a static field that enhances the MR signal

 

Also, electromagnetic waves with wavelength of more than one order of magnitude longer than the human body (cf. 20-meter band or 14-MHz band) are considered quasi-static for it. They are thought to represent a near-zone reactive field, thereby being equivalent to a uniform exposure. This includes the ELF waves such as those from the 50/60 Hz mains electricity/grid power. These waves could therefore correspond to a static field which could enhance the magnetic resonance signal. Magnetoquasistatic waves recently developed for navigation are also relevant.

 

More details: 

http://www.information-book.com/science-tech-general/human-body-em-field-interaction/

http://www.information-book.com/science-tech-general/human-body-em-field-interaction-ii/

 

 

 

Microwave ionization could create charges on the body surface or the environment that could be used to read the magnetic signal

 

Microwave radiation is termed non-ionizing because a microwave photon does not have enough energy to extract an electron and cause ionization. However, upon certain conditions microwaves can mediate ionization. In this way, they could create charges on the body surface or the environment (cf. electron clouds) that could be used to read magnetic fields either by magnetic resonance or by quantum effects/atom interferometery/Aharonov-Bohm electromagnetic potential detection.

 

More details:

https://www.information-book.com/science-tech-general/ionization-by-microwaves/

 

 

Biological responses on conditions of ion magnetic resonance and ion cyclotron resonance - The ion forced oscillation hypothesis

 

Certain low frequencies induce strong biological responses either on their own or when used to modulate electromagnetic waves. This may be due to resonance. An example is 16Hz, the ion cyclotron resonance frequency of potassium ions in the Earth's magnetic field, which is associated with calcium efflux and increased membrane permeability.  There exist examples of biological responses upon modulation of 450 MHz and 2.45 GHz carrier waves with 16 Hz. The ion forded oscillation hypothesis may complement the ion cyclotron resonance hypothesis. Additionally, biological responses are induced on ion mangetic resonance condtions. 

 

More details:

https://www.information-book.com/science-tech-general/ion-magnetic-resonance-cyclotron-resonance-forced-oscillation/

(https://www.information-book.com/electromagnetic-harassment-health-attacks/mechanisms-ii-of-directed-energy-harassment/)