LORETA-KEY is a software program implemented by Roberto Pascual-Marqui that implements the LORETA source localization algorithm (“low resolution brain electromagnetic tomography”). The software is available from the LORETA home page. Using LORETA-KEY, you can make a distributed source reconstruction for EEG data, using a three-shell spherical head model registered to a standardized stereotactic space (based on MNI brain). The source reconstruction is restricted to cortical gray matter.

The LORETA2FIELDTRIP function can be used to read in the resulting files (*.slor, *.lorb) from the LORETA-KEY software. The output of the LORETA2FIELDTRIP function is a matlab structure that is equivalent to the structures that result from the ft_sourceanalysis function in FieldTrip. Hence, you can use its output as input in the FieldTrip ft_sourcegrandaverage and/or ft_sourcestatistics functions.

Using sourcestatistics, you can perform a random-effect parametric or non-parametric statistical test based on a single-voxel statistic or based on a spatio-temporal cluster statistic (only non-parametric). Both the parametric and non-parametric statistical tests implemented in FieldTrip have support for correcting for the multiple comparison problem.