Hello Francois,
The concept of "Seed" is mentioned in this tutorial: https://neuroimage.usc.edu/brainstorm/Tutorials/Scouts
and it is introduced as follows: Seed : Index of the central point of the scout (or the most relevant one).
I would like to know for different physiological partitions, such as Boardman partition, Desikan-Killiany partition, etc., how are their Seeds determined?