GPS is a GUI driven analysis tool for performing Kalman filter driven Granger Causation Analysis of MRI-constrained source space reconstructions of MEG/EEG data.


GPS software
Step-by-step guide for analyzing using GPS

Acknowledgements and Support

The Granger Processing Stream (GPS) was developed by the Gow Group in the Department of Neurology at the Massachusetts General Hospital and the Athinoula A. Martinos Center for Biomedical Imaging with support from the National Institute of Deafness and Communicative Disorders (R01 DC003108). It also benefited from the support of the MIND Institute and a NCRR Regional  Resource Grant (41RR14075) for the development of technology and analysis tools at the Martinos Center.

Many people contributed to the development of this stream including David Gow, Jennifer Segawa, Ricky Sachdeva, Corey Keller, Mark Vangel, Reid Vancelette, Bruna Olson, David Caplan and Seppo Ahlfors.  Conrad Nied made invaluable contributions to the approach, and is responsible for coding and developing GPS’s graphic user interface.


For the time being, all citations of GPS should cite this manual, and the overview of our approach provided in:

Gow, D.W., & Caplan, D. (2012). New levels of language processing complexity and organization revealed by Granger causation. Frontiers in Psychology, 3, 506. doi: 10.3389/fpsyg.2012.00506

The Kalman filter technique we use comes from:

Milde, T., Leistritz, L., Astolfi, l., Miltner, W.H.G., Weiss, T., Babiloni, F., & Witte, H. (2010). A new Kalman filter approach for the estimation of high-dimensional time variant  multivariate AR models and its application in analysis of laser-evoked brain potentials. NeuroImage, 50, 960-969. Doi: 10.1016/j_neuroimage_2009.12.110.


GPS is a GUI-based program written by A. Conrad Nied based on analyses developed by David Gow and members of his lab at the Massachusetts Hospital to automate MNE and FSL analyses of MR-constrained MEG/EEG data and to perform Kalman filter based Granger analyses of those data. Copyright © 2014. A. Conrad Nied and David Gow.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the license or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warrantee of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details (


David Gow (

Please let us know what kind of experiences you have with GPS and tell us about any publications that come from it.