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Speckle is a random field intensity pattern produced by the mutual interference of partially coherent beams that are subject to minute temporal or spatial fluctuations. If the field of particles is nonstatic, photographing the pattern results in an image that is blurred over the exposure time of the recording device. The velocity information in the blur can be extracted and mapped to contrast using statistical arguments.  
(a) As the surface generating the speckle moves or is deformed (for example, the motion of RBCs inside blood vessels), the speckle patterns shift. (b) Imaging for speckle formation.
  LASER Speckle Contrast Imaging (LSCI) is an optical technique for imaging blood flow and microvasculature that:
Is high resolution, high contrast, and wide field, able to pick up individual vessels of about 20 ?m in a 4mm x 4mm area without scanning;
Is minimally invasive (performed in a thin skull preparation), and long term friendly, requiring no contrast agent;
Yields hemodynamic information including blood flow, vasculature, and oxygenation concentration;
Can be integrated with other systems.
  There are three directions for the LSCI neuroimaging group:
LSCI for functional brain study: creating a migraine model and investigating optogenetically-guided plasticity following limb injury;
Clinical application of LSCI: tumor angiogenesis in rat brain;
A head-mountable LSCI system for awake, behaving animals.
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