Adaptive enhancement of magnetoencephalographic signals via multichannel filtering

A time-varying spatial/temporal filter for enhancing multichannel magnetoencephalographic (MEG) recordings of evoked responses is described. The filter is based on projections derived from a combination of measured data and a priori models of the expected response. It produces estimates of the evoked fields in single-trial measurements. The estimates can reduce the need for signal averaging in some situations. The filter uses the a priori model information to enhance responses where they exist, but avoids creating responses that do not exist. Examples are included of the filter´s application to both MEG single-trial data containing an auditory evoked field and control data with no evoked field