Detection of Magnetic Fields Created by Biological Tissues

摘要

The recording of magnetic fields associated with cellular current flow in nerve and muscle fibers was first reported nearly three and a half decades ago. These magnetic fields are detected using a room-temperature toroidal pickup coil called the neuromagnetic current probe. These probes can be employed to measure action currents of biological tissues while they are resting in their own natural settings or in saline baths, thereby reducing the risk associated with elevating and drying the tissues in the air during experiments. These magnetic fields are relatively insensitive to muscle movement since these probes are not directly connected to the tissues, and distortions of the recorded data due to changes in the electrochemical interface between the probes and the tissues are minimal. In this paper, the magnetic fields of single nerve axons, muscle fibers and nerve bundles are discussed. Furthermore, one of the possible applications of the neuromagnetic current probe to the intraoperative assessment of damaged nerve bundles is discussed.