  While it is still not possible to describe the neural-level connections of
the human brain, we can map the human connectome with several hundred vertices,
by the application of diffusion-MRI based techniques. In these graphs, the
nodes correspond to anatomically identified gray matter areas of the brain,
while the edges correspond to the axonal fibers, connecting these areas. In our
previous contributions, we have described numerous graph-theoretical phenomena
of the human connectomes. Here we map the frequent complete subgraphs of the
human brain networks: in these subgraphs, every pair of vertices is connected
by an edge. We also examine sex differences in the results. The mapping of the
frequent subgraphs gives robust substructures in the graph: if a subgraph is
present in the 80% of the graphs, then, most probably, it could not be an
artifact of the measurement or the data processing workflow. We list here the
frequent complete subgraphs of the human braingraphs of 414 subjects, each with
463 nodes, with a frequency threshold of 80%, and identify 812 complete
subgraphs, which are more frequent in male and 224 complete subgraphs, which
are more frequent in female connectomes.
