Modelling and Analysis of Magnetic Fields from Skeletal Muscle for Valuable Physiological Measurements

MagnetoMyoGraphy (MMG) is a method of studying muscle function via weak magnetic fields generated from human active organs and tissues. The correspondence between MMG and electromyography means directly derived from the Maxwell-Ampère law. Here, upon briefly describing the principles of voltage distribution inside skeletal muscles due to the electrical stimulation, we provide a protocol to determine the effects of the magnetic field generated from a time-changing action potential propagating in a group of skeletal muscle cells. The position-dependent and the magnetic field behaviour on account of the different currents in muscle fibres are performed in temporal, spectral and spatial domains. The procedure covers identification of the fiber subpopulations inside the fascicles of a given nerve section, 2 characterization of soleus skeletal muscle currents, check of axial intracellular currents, calculation of the generated magnetic field ultimately. We expect this protocol to take approximately 2-3 hours to complete for whole finite-element analysis. Introduction With the rapid development of nanoscale magnetic sensors, the non-invasive biomagnetic recording has been a reliable and robust approach for biomedical applications, ranging from clinical diagnoses to human-computer-interaction. The assessment of muscle activity is essential in nowadays diagnosis of peripheral muscle and nerve diseases, in fundamentals of movement neuroscience and in technologies for motor rehabilitation. Detecting weak magnetic signals derived from human skeletal muscle, first formally proposed in 1972 and it was called Magnetomyography (MMG). The scientists have recorded the magnetomyogram signal as one component of the magnetic field vector for time at the point of measurement, in which the magnetic fields are by cause of currents produced from the skeletal muscle. Over the past four decades, a key challenge has been developing effective methods that offer both high spatial and temporal resolutions. Conventionally, the muscle activity is recorded and analysed electrically with Electromyography (EMG) techniques in the clinic from the skin’s using metal or stainless-steel electrodes. However, the electric signals suffer from poor spatial resolution when recording EMG signals noninvasively and sensors implanted in the muscle, for more accurate measurements with highdensity needle recording probes, face biocompatibility issues. However, in addition to being painful, the penetration of the needle into the muscle disturbs the muscle structure and function. Moreover, in chronic implants, such as for the control of motor prostheses, the interface between the metal contacts of the sensor and the muscle tissue changes over time, leading to infection and rejection by the body. Therefore, a different paradigm enables non-invasive monitoring with the macro-fidelity, temporal, and spatial resolutions and better sensor location and quickly screening without electrical contacts. Therefore, the MMG is becoming an alternative method to measure muscle activity and addresses both limitations of the EMG method.