Image correlation spectroscopy: principles and applications.

Image correlation spectroscopy (ICS) was developed as the imaging analog of fluorescence correlation spectroscopy. Using standard fluorescence microscopy image series as input, different versions of ICS can be used to extract parameters on the molecular transport properties (diffusion and flow) and oligomerization state for fluorescently labeled species in cells. This review introduces the various forms of spatial and temporal ICS and discusses application of these methods to reveal properties of the biomolecules that can be measured from standard fluorescence image time series sampled from cells and neurons.