Laser speckle analysis synchronised with cardiac cycle

Abstract

We present an improved Laser speckle imaging approach to investigate the cerebral blood flow response following function stimulation of a single vibrissa. By synchronising speckle analysis with the cardiac cycle we are able to obtain robust averaging of the correlation signals while at the same time removing the contributions due to the pulsation of blood flow and associated tissue adaptation. With our inter-pulse correlation analysis we can follow second-scale dynamics of the cortical vascular system in response to functional brain activation. We find evidence for two temporally separated processes in the blood flow pattern following stimulation we tentatively attribute to vasodilation and vasoconstriction phases, respectively.