the first step of GCN is to construct a populational graph.
there are three types of brain graphs we could choose:
- spatial neighborhood
- structural covariance
- RSFC
In the 2nd and 3rd graphs, we need to additionally construct a sparse KNN graph because it is very dense which might cause computational problems
Note, previously I had made a mistake by taking the weakest connections for the KNN graph, which has worsen the performance of GCN. Now it worked and we could compare them.