Interpretations of response fluctuations: neurons, networks and simple behavior

Trial-by-trial response variation is ubiquitous in practically every observable neural scale. I will describe our experimental efforts to measure and interpret these fluctuations over a wide range of timescales in single neurons and large-scale networks, as well as in simple behavioral (psychpohysical) settings. While the statistical nature of the fluctuations is comparable in these different levels of organization, it is difficult - maybe impossible, maybe even meaningless - to attempt accounting for macroscopic fluctuations in terms of microscopic dynamics. Alternative interpretations are offered and experimentally demonstrated.