  This work introduces the phenomenon of Collective Almost Synchronization
(CAS), which describes a universal way of how patterns can appear in complex
networks even for small coupling strengths. The CAS phenomenon appears due to
the existence of an approximately constant local mean field and is
characterized by having nodes with trajectories evolving around periodic stable
orbits. Common notion based on statistical knowledge would lead one to
interpret the appearance of a local constant mean field as a consequence of the
fact that the behavior of each node is not correlated to the behaviors of the
others. Contrary to this common notion, we show that various well known weaker
forms of synchronization (almost, time-lag, phase synchronization, and
generalized synchronization) appear as a result of the onset of an almost
constant local mean field. If the memory is formed in a brain by minimising the
coupling strength among neurons and maximising the number of possible patterns,
then the CAS phenomenon is a plausible explanation for it.
