Time averaged localisation of electrophysiological activities in living being - superimposing by strong background noise measured using model of current density in absence of electrophysiological activities using multi-channel system

摘要

The localisation method involves measuring electrophysiological activities occurring in the living 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 in to cells, each having a current density (j). The multi-channel measuring system (12) with an evaluation unit (18) measures the background noise at measurement places at several points of time (t'i), with the absence of electrophysiological activities (8). So that a background noise covariance matrix (C) can be formed. A difference matrix (Z) is formed from the difference of the measurement value correlation matrix (D) and the background co-variance matrix (C). The square of the diagonal elements of the current density matrix (S) are used for correct representation of a current density distn. in the examination zone determined in a second measurement interval in the examination zone. ADVANTAGE - Time averaged localisation is made if measurement values determined outside examination zone at measurement places of magnetic field produced by activities are superimposed by strong background noise.