The Measurement of Spinal Cord Evoked Magnetic Fields by Vector SQUID Biomagnetometer

Abstract

Biomagnetometry is a powerful method for the investigation of the neural activity. We developed a multi channel superconducting quantum interference devices (SQUIDs) biomagnetometer system for the measurement of the evoked magnetic field from stimulated spinal cords. The system is equipped with three dimensionally configured SQUID vector gradiometers, which can detect not only the radial components of the magnetic field to the subject but also the tangential components. With the system, we could successfully observe the distribution of the evoked magnetic field corresponding to neuronal signals transmitting in the spinal cord of small animals as momentarily changing vector map.