EEG Simulation: Variation of Spectral Envelope, Pulse Synchrony and ~40 Hz Oscillation.

Abstract

A simplified simulation of cortical neuronal interaction reproduces some features of the electrocorticogram (ECoG). Nonspecific activation acts to control the transfer function of the simulated cortex, and thus determines the relative amplitude of waves generated by rhythmic inputs.When concurrent asynchronous excitatory inputs to separate, local, cortical sites are introduced, the simulation reproduces both gamma band (40Hz) ECoG activity and synchronous oscillation of action potential pulse density at the seperate sites. The gamma band ECoG and pulse synchrony effects depend on different mechanisms - the former upon local excitatory/inhibitory interactions, and the latter on cortico-cortical interactions. The pattern of synchronous activity depends upon both structural and dynamic aspects of gain. Dynamic properties which are independent of scale in the simulation, describe intercellular, intercolumnar or interareal phenomena, all in accord with physiological findings (Singer and Gray 1995).