A Bayesian test for the appropriateness of a model in the biomagnetic inverse problem

This paper extends the work of Clarke [1] on the Bayesian foundations of the biomagnetic inverse problem. It derives expressions for the expectation and variance of the a posteriori source current probability distribution given a prior source current probability distribution, a source space weight function and a data set. The calculation of the variance enables the construction of a Bayesian test for the appropriateness of any source model that is chosen as the a priori infomation. The test is illustrated using both simulated (multi-dipole) data and the results of a study of early latency processing of images of human faces. [1] C.J.S. Clarke. Error estimates in the biomagnetic inverse problem. Inverse Problems, 10:77--86, 1994.Comment: 13 pages, 16 figures. Submitted to Inverse Problem

DESIGN AND ASSESSMENT OF SQUID MAGNETOMETERS USING RECIPROCITY METHODS

It is shown that the reciprocity method provides a simple technique for the design of second order gradiometers and the calculation of an instrument function. A small sample of known susceptibility has been used to map out the response of a gradiometer for comparison with the calculation. A simple analytical expression for the effect of superconducting "balancing" tabs in gradiometers is developed