  For more than a decade now, we can discover and study thousands of cerebral
connections with the application of diffusion magnetic resonance imaging (dMRI)
techniques and the accompanying algorithmic workflow. While numerous
connectomical results were published enlightening the relation between the
braingraph and certain biological, medical, and psychological properties, it is
still a great challenge to identify a small number of brain connections,
closely related to those conditions. In the present contribution, by applying
the 1200 Subjects Release of the Human Connectome Project (HCP), we identify
just 102 connections out of the total number of 1950 connections in the
83-vertex graphs of 1065 subjects, which -- by a simple linear test --
precisely, without any error determine the sex of the subject. Very
surprisingly, we were able to identify two graph edges out of these 102, if,
whose weights, measured in fiber numbers, are all high, then the connectome
always belongs to a female subject, independently of the other edges.
Similarly, we have identified 3 edges from these 102, whose weights, if two of
them are high and one is low, imply that the graph belongs to a male subject --
again, independently of the other edges. We call the former 2 edges
superfeminine and the first two of the 3 edges supermasculine edges of the
human connectome. Even more interestingly, one of the edges, connecting the
right Pars Triangularis and the right Superior Parietal areas, is one of the 2
superfeminine edges, and it is also the third edge, accompanying the two
supermasculine connections, if its weight is low; therefore it is also a
"switching" connection.

Neurons and Cognition