  A network of propagating nonlinear oscillatory modes (waves) in the human
brain is shown to generate collectively synchronized spiking activity
(hypersynchronous spiking) when both amplitude and phase coupling between modes
are taken into account. The nonlinear behavior of the modes participating in
the network are the result of the nonresonant dynamics of weakly evanescent
cortical waves that, as shown recently, adhere to an inverse frequency-wave
number dispersion relation when propagating through an inhomogeneous
anisotropic media characteristic of the brain cortex. This description provides
a missing link between simplistic models of synchronization in networks of
small amplitude phase coupled oscillators and in networks built with various
empirically fitted models of pulse or amplitude coupled spiking neurons.
Overall the phase-amplitude coupling mechanism presented in the Letter shows
significantly more efficient synchronization compared to current standard
approaches and demonstrates an emergence of collective synchronized spiking
from subthreshold oscillations that neither phase nor amplitude coupling alone
are capable of explaining.
