Figure 1.
The functional connectome: layout and communities.
The full brain contains about 43413 3-mm cubic voxels for AAL-90 (A), AAL-512(B) and AAL-0124 (C) template. On average 6 functional communities were found. They are colored distinctly within multiple axial slices and 3D rendered on MNI152 standard brain surface (Bottom). To highlight the overall layout at a sparse 2% connection density, the functional connectome was further visualized as a network layout with the same colors (Top).
Figure 2.
Distributions of the most informative variables contained in the set across communities.
Figure 3.
Reproducibility of the causal flow from mPFC (purple sphere) when using pairwise GC(left) and PCGCt (right) under .
Relative frequency with which a voxel was selected as a hub for outgoing information.
Figure 4.
Visualization of the group-level voxel-wise directed graph.
Upper panel: layout at a sparse 2.4% connection density, 8156 voxels with degree>11 are displayed; the 17 bigger communities (detected from the directed network at group level) are indicated by different colors. Lower panel: the spatial distributions of the voxels in the upper panel are mapped on the anatomical image with the same colors.
Figure 5.
The spatial distribution of hub voxels in a binary graph obtained keeping all the weights higher than a threshold of 0.3, with unitary value, and setting the rest to zero.
In the top sagittal views, red indicates the incoming network hubs, blue the outgoing network hubs, while green the common hubs of incoming and outgoing network. Concerning the axial views, 1-3rd (5–7th) rows indicate the BC/CC/DC incoming network hubs. In 4th (8th) row, yellow indicates incoming (outgoing) regions which are hubs for one measure (hub-score of 1), red indicates incoming (outgoing) regions which are hubs for two measures (hub-score of 2), while green indicates regions which are hubs for all three measures (hub-score of 3). The last row indicates the regions that are at the same time hubs for incoming and outgoing network with hub score of at least 2.
Figure 6.
The spatial distribution of hub voxels in a graph binarized with a threshold .
The first row illustrates the spatial distribution of global functional connectivity density hubs. The second (third) row indicates the DC incoming (outgoing) network hubs. The last row indicates the regions which are DC hubs both for FC and EC (incoming/outgoing) networks.
Figure 7.
Results of the different PCGC algorithms on simulated data (k = 20). Left: pairwise GC, center: PCGCd, right: PCGCt.