Resilience of Neural Electronics to High Magnetic Fields

With the advent of neuronal oscillators in bioelectronic medicine, it has become increasingly important to understand the effect of magnetic fields on the biological rhythms they produce. In particular, cardiac pacemakers must be resilient to the magnetic fields applied during magnetic resonance imaging, but it is not known whether the nonlinearity of the neuron response would amplify some the known effects of magnetic fields in semiconductor devices. Here, we have performed a series of experiments probing the oscillations of a silicon neuron in a static magnetic field of 3T applied in the plane of the substrate and perpendicular to it. The neuron was fabricated from complementary metal-oxide-semiconductor integrated circuits, which integrated currents in the nA range to compute the output of the Hodgkin-Huxley model. The experiment reveals a small magnetic field-induced dephasing of neuron oscillations which is slightly larger when the magnetic field is in the plane rather than perpendicular to the plane. This is interpreted in terms of the differences in diffusion coefficients of cyclotron and magnetoelectric skipping orbits at room temperature.