Comparison of temporal response to cerebral blood flow measured by laser speckle flowgraphy and laser Doppler flowmetry

Cerebral blood flow (CBF) change of mice during whisker stimulation is measured by laser speckle flowgraphy (LSFG) and laser Doppler flowmetry (LDF). Laser speckle flowgraphy (LSFG) has been used to obtain the two-dimensional distribution of the blood flow in tissue as well as scanning laser Doppler flowmetry (LDF). There are several parameters of LSFG to obtain the blood flow maps and the distribution change of blood flow. In this study, we calculate four parameters from the speckle pattern to measure CBF in awake mice. The temporal resolution of LSFG is likely to be less than that of LDF. The temporal changes in CBF obtained from the four parameters calculated from the speckle pattern detected by a common CCD camera are compared with those measured by LDF. The time courses of CBF change measured by LSFG highly correlate with those by LDF. The results indicate that the temporal response of LSFG is sufficient to measure CBF change evoked by brain activations.