  We report on the origin of synchronized bursting dynamics in various networks
of neural spiking oscillators, when a certain threshold in coupling strength is
exceeded. These ensembles synchronize at relatively low coupling strength and
lose synchronization at stronger coupling via spatio-temporal intermittency.
The latter transition triggers multiple-timescale dynamics, which results in
synchronized bursting with a fractal-like spatio-temporal pattern of spiking.
Implementation of an appropriate technique of separating oscillations on
different time-scales allows for quantitative analysis of this phenomenon. We
show, that this phenomenon is generic for various network topologies from
regular to small-world and scale-free ones and for different types of coupling.
