Blood flow fluctuations in cerebral cortex microvessels

Studies on the dynamics of the blood flow in cerebral microvessels with the diameter of erythrocyte flow (5-13 micron) carried out by the cinema-TV method showed that the linear velocity of the blood flow in microvessels experienced considerable fluctuations the amplitude of which varied within 10 to 1500 micron/s and the period within 0.2 to 7 s. It was established that variations in linear velocity of the blood flow were most frequently observed during 0.5-1 s. The autocorrelation analysis showed there was periodicity in the blood flow fluctuations in most microvessels which varied within a wide range of 0.3 to 3 s. A linear dependence was found between the amplitude and the period of fluctuations. The observed variations in the blood flow are likely to be caused by the changes in local resistance when leukocytes and erythrocyte aggregates passed through microvessels.