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. 2019 Aug 13;24:101981. doi: 10.1016/j.nicl.2019.101981

Table 1.

Iterative subdividing scheme for density-based clusters.

Relative hierarchy Mother cluster size (cluster annotation) No. of Mother Clusters (cluster annotation) No. of main clusters No. of tiny clusters Tiny clusters – Average size Tiny clusters – Cumulative size Orphan voxelsa Reachability threshold
0 4 (#1, #6, #80, #71) 16 123 8.59 1056 0 1.25 × e−3
1 25961 (#1) 2 (#1.1, #1.5) 18 62 10.6 656 547 9.47 × e−4
2 14,183 (#1.1) 1 (#1.1.1) 18 35 13.2 463 134 8.05 × e−4
2 4121 (#1.5) 0 20 62 13.4 834 255 3.41 × e−4
3 8818 (#1.1.1) 1 (#1.1.1.1) 20 26 11.0 287 103 6.20 × e−4
4 2703 (#1.1.1.1) 0 13 83 12.5 1040 508 0
1 17,529 (#6) 2 (#6.61, #6.84) 21 52 9.65 502 622 1.06 × e−3
2 4829 (#6.61) 0 12 106 11.5 1215 1185 0
2 2766 (#6.84) 0 8 81 9.6 776 1562 0
1 4442 (#71) 0 7 121 9.82 1188 1542 0
1 9130 (#80) 1 (#80.588) 18 108 11.0 1186 1879 8.72 × e−4
2 4520 (#80.588) 1 (#80.588.1545) 10 58 10.4 606 722 1.08 × e−19
3 2319 (#80.588.1545) 1 (#80.588.1545)b 0 0 0 0

An iterative scheme was applied for hierarchical clustering: the reachability threshold was initially set to form 20 mother/main clusters along with any number of tiny clusters. The same scheme was repeated for any mother cluster formed among subdivisions. Eventually, the brain was parcellated into 1 mother, 181 main, and 917 tiny clusters.

Mother clusters referred to those >1850 voxels (~50 cm3); main clusters were > 37 voxels (~1 cm3); and tiny clusters were ≤ 37 voxels.

Cluster size are presented in voxel, where each voxel is 0.027 cm3.

a

During subdivision clustering process, some voxels could not be assigned to any of sub-clusters generated at corresponding hierarchical level, and are referred to as “orphan” voxels. The column depicts the total number of orphan voxels generated at corresponding sub-clustering level.

b

One of the mother clusters at the 3rd hierarchical level (#80.588.1545) could not be resolved to smaller main or tiny clusters.