Noise and diversity effects in a homeostatic model of wake-sleep cycle

The effect of noise and heterogeneity is studied in a multi-neuron
generalization of a two-neuron model of wake-sleep cycle introduced
recently [S. Postnova, K. Voigt, H.A. Braun, J. Biol. Rhythms 24, 523
(2009)]. This minimal but physiologically plausible two-neuron model
introduced a mechanism of homeostatic regulation of sleep based on
Orexin/Hypocretin, a co-transmitter of the lateral hypothalamus, and on
Glutamate.
It is shown that in the presence of an external periodic signal,
representing e.g. a daily light stimulus or a circadian cycle, there are
suitable levels of heterogeneity of the neuronal couplings or of the
noise currents that are optimal for the system response to the external
stimulus.