Abstract
Human fingers are an excellent organ in sensory function as well as motor function. We hypothesized that blood vessels of the fingers are dynamically regulated by sympathetic outflow during concentrated finger perception. To identify this hypothesis, we measured finger skin blood flow (FSBF), heart rate (HR), and mean arterial blood pressure (MAP) during finger reading performed under the blind condition. A two-dimensional image of FSBF (palmar digital artery of the second-third fingers; scan area, 5X5cm; spatial resolution, 1mm2) was measured using a laser Doppler perfusion imaging equipment. Finger skin vascular conductance was calculated from a ratio of the blood flow and MAP. The subjects were instructed to read a flat plate with raised letters (diameter, 3mm; height, 1mm) for 15 sec by the forefinger, and to touch the flat plate without any raised letters. HR and MAP slightly increased during finger reading but unchanged during touching the blank plate. FSBF was decreased during touching the plate with the raised letters, whereas the blood flow did not be affected by touching the flat plate. The mean decrease in FSBF was 19±3% during finger reading, while contralateral FSBF unchanged. The changes in finger skin vascular conductance followed the changes in FSBF, because the changes in MAP were negligible. These results indicated that blood flow in the fingers is decreased during finger reading. We considered that sympathetic outflow to the hand may contribute to this decrease in blood flow. [Jpn J Physiol 54 Suppl:S91 (2004)]
