Localisation of electrophysiological activities overlaid by strong background - measuring using model of current density in absence of electrophysiological activities using multi-channel measuring system to form background co-variance matrix

摘要

The localisation method involves measuring electrophysiological activities occurring in the living being within an examination zone, produce a magnetic field (10), at measurement points outside the examination zone. This zone in the reconstructed model of the activities is divided into cells, each having a current density (j). The multi-channel measuring system (12) includes a multi-channel SQUID system (16), a gradiometer system (14) and an evaluation unit (18). It measures the background noise at measurement places, with the absence of electrophysiological activities (8). So that a background noise co-variance matrix (C) can be formed, which is used in conjunction with the measurement value correlation matrix (D). The current density (j) is used for the place correct representation of the distribution of the electrophysiological activities. ADVANTAGE - Negative influence of superimposed background noise using Wiener reconstruction on localisation accuracy is substantially eliminated using matrices C and D,. For magnetic fields superimposed by strong uncorrelated background noise.