  Neuronal dynamics is intrinsically unstable, producing activity fluctuations
that are essentially scale-free. Here we show that while these scale-free
fluctuations are independent of temporal input statistics, they can be
entrained by input variation. Joint input output statistics and spike train
reproducibility in synaptically isolated cortical neurons were measured in
response to various input regimes over extended time scales (many minutes).
Response entrainment was found to be maximal when the input itself possesses
natural-like, scale-free statistics. We conclude that preference for natural
stimuli, often observed at the system level, exists already at the elementary,
single neuron level.
