Just about everyone knows a person who seems to know an unusually large
number of people, has the latest information on how they are doing, and
can quickly put them in touch with a potential friend or colleague. In the
study of social network theory, these people are known as "hubs" or
Similarly, the human brain appears to be organized so that a
small number of key brain regions have many connections to other regions
of the brain and likely act as hubs to facilitate the transfer of
information. This pattern of connectivity can be measured by examining the
functional connections among brain regions (measuring how their activity
is spontaneously correlated; see Buckner et al., 2009
), or by examining the
structural connections via which neural signals are transmitted. The paper
by van den Heuvel and Sporns uses a technique to measure the white matter
fiber tracts that make up the structural connectivity of the brain.
They find that a small set of brain regions have both a high degree of
interconnectedness with other...