Ltspice

Biocytin-injected neuron morphology (Fig. 1a) was traced to create a vector representation, which was imported into COMSOL multiphysics simulation environment (COMSOL Inc., Stockholm, Sweden). Geometry was extruded to a height of 1.1 μm (Fig. 1c). The membrane was modeled with exterior surface area 1450 μm², volume 14.39 μm³, relative permeability ε=1, relative permittivity μ=1, electrical conductivity σ=1e-13 S/m, surrounding the intracellular environment, surface area 1431.1 μm², volume 463.77 μm³, which was modeled using the electrical properties of cerebrospinal fluid, ε = 1.09e2, μ = 1, σ = 2 S/m. Representative action potential data was extracted from voltage traces of current clamp recordings (Fig. 3a, sampling frequency = 6103.5 Hz, total recording time 23:51.768) and used as input for an electronic circuit simulation software (LTSPICE, Analog Devices, Norwood, MA). The cell-device interface was simulated as a 100 MΩ resistor in parallel with a 15 pF capacitor. The current was measured across this interface and downsampled to 20 key values, which were applied as inputs in COMSOL on one face of the neuron in a parametric sweep stationary study for simulations of magnetic flux density and field strength during action potentials to compare the response of the naïve model neuron to that of the modelled cell-device interface (Fig. 3c).