The brain connectome is represented by a connectivity matrix. The adjacency matrix is represented differently according to the type of* Graph*. An adjacency matrix is square, and its elements indicate whether the pairs of vertices are connected or related. As a convention, its diagonal elements are set to 0, as a node is not connected to itself.

A* Graph* can have different characteristics. To name some, a *Graph* can be weighted or binary, directed or undirected, and unilayer or multilayer. A visual representation of the representation of unilayer *Graphs *in BRAPH 2 is shown below: