Measurement of Distribution of Blood-flow Change in Exposed Cortex by Laser Speckle Flowgraphy

The change in the cortical blood flow of guinea pigs during auditory stimulation is measured by laser speckle flowgraphy (LSFG). Accuracy of LSFG depends on the number of the frames for the blood flow calculation. The blood-flow maps of rotating disks and cortical tissues are calculated from various numbers of frames of speckle pattern, and the influence of the statistical error and averaging effect on the results is evaluated to optimise the LSFG system. The blood-flow map obtained from successive 24-30 frames can appropriately identify the change in the blood flow caused by auditory stimulation.