Fig. 2.

Schematic representation of the procedure for the seed-based resting state functional connectivity. Each seed of interest (in the figure an example is provided for the left middle frontal gyrus) was defined in MNI space and moved to each subject native space. From each seed, mean time-series were extracted and subject-level maps of all positively and negatively predicted voxels for each regressor were obtained. Subject-level maps were finally registered to the MNI standard template and were ready for the statistical analysis. Here we provided the illustrative example of analysis at baseline: seed-based functional connectivity was investigated in each patient group versus the matched group of controls using a general linear model which includes the group as independent factor. Abbreviations: ALS = amyotrophic lateral sclerosis; HC = healthy controls; L = left; MFG = middle frontal gyrus.