  Functional magnetic resonance imaging (fMRI) techniques have contributed
significantly to our understanding of brain function. Current methods are based
on the analysis of \emph{gradual and continuous} changes in the brain blood
oxygenated level dependent (BOLD) signal. Departing from that approach, recent
work has shown that equivalent results can be obtained by inspecting only the
relatively large amplitude BOLD signal peaks, suggesting that relevant
information can be condensed in \emph{discrete} events. This idea is further
explored here to demonstrate how brain dynamics at resting state can be
captured just by the timing and location of such events, i.e., in terms of a
spatiotemporal point process. As a proof of principle, we show that the resting
state networks (RSN) maps can be extracted from such point processes.
Furthermore, the analysis uncovers avalanches of activity which are ruled by
the same dynamical and statistical properties described previously for neuronal
events at smaller scales. Given the demonstrated functional relevance of the
resting state brain dynamics, its representation as a discrete process might
facilitate large scale analysis of brain function both in health and disease.
