The Human Brain Network - Biological Networks - page 211

Fig. 9.5. Structural connectivity gives rise to fluctuating neural dynamics that results in time-
dependent patterns of functional connectivity (data replotted from Honey et al. 2007). The
structural network of fiber pathways between 47 macaque cortical regions is shown in panel A -
these connections do not change pattern or strength over time. However, samples of functional
dynamics (displayed as overlapping windows of 30 seconds of neural activity, panel B) reveal
significant fluctuations in centrality for given nodes. For example, nodes with, on average, high
centrality (see Fig. 9.4) exhibit significant fluctuations in centrality over time. As a consequence,
the precise pattern of functional connectivity will exhibit time-dependent changes on a time scale of
seconds to minutes (panel C).
regions (Zemanova et al ., 2006), as well as a hierarchical modular organization
of functional connectivity that matched that found in structural connectivity
(Zhou et al ., 2006). An ambitious large-scale model of spiking neural dynamics
structurally based on DTI-derived whole-head cortical connectivity was
introduced by Izhikevich and Edelman (2008) and showed complex patterns of
spike dynamics in spontaneous neural activity. More detailed models of human
brain dynamics at multiple time scales are likely to emerge in the near future,
incorporating network connectivity data ranging from cells to systems (e.g.
Markram, 2006).