"... Intriguingly, the amplitude of ongoing oscillations, such as measured in EEG recordings, fluctuates irregularly, with episodes of high amplitude (HAE) alternating with episodes of low amplitude (LAE).
Here, we show that transitions between HAE and LAE in the alpha/beta frequency band occur in a generic neuronal network model consisting of interconnected inhibitory (I) and excitatory (E) cells that are externally driven by sustained depolarizing currents(cholinergic input) and trains of action potentials that activate excitatory synapses.
In the model, action potentials onto inhibitory cells represent input from other brain areas and desynchronize network activity, being crucial for the emergence of amplitude fluctuations.
Avella Gonzalez OJ, van Aerde KI, van Elburg RA, Poil SS, Mansvelder HD, Linkenkaer-Hansen K, (2012) External drive to inhibitory cells induces alternating episodes of high- and low-amplitude oscillations. PLoS Comput Biol 8:e1002666-40 [PubMed]