Brain connectivity measure — the direct transfer function — advantages and weak points

In this article we briefly investigate the Directed Transfer Function, the DTF, a causality measure used in determination of brain connectivity patterns, characterizing specific brain states/activities. Introduced by Kaminski and Blinowska two decades ago, it was claimed that this measure is the proper measure for complexity involved in brain activity, correcting incapacity and essential weakness of original Granger causality measures. This measure of brain connectivity reached broad application in very exciting brain activity modeling applied numerously by many research teams. Some of DTF advantages and weak points are analyzed in this article.