Individual differences in blood volume and oxygenation in the brain during a cognitive task based on time-resolved spectroscopic measurements

Abstract

Although a time-resolved near-infrared spectroscopy (TRS) system is difficult to make a measurement into 10 s or less at the moment, the system has a great advantage that it measures absolute values of hemoglobin concentrations. In the present study, using a device equipped with a TRS system, we examined individual differences in changes in cerebral oxygenated, deoxygenated, and total hemoglobin concentrations during two repetitive executions of a cognitive task, and compared these with data from our previous studies performed with a CWS system. As a result, large individual differences were also observed in changes in the cerebral hemoglobin concentrations during a cognitive task in this study using a TRS system. We therefore conclude that large individual differences observed in changes in the cerebral hemoglobin concentrations during a cognitive task in our previous studies using a continuous wave nearinfrared spectroscopy (CWS) system would probably be universal, although a CWS system includes the limitation that the absolute value is unable to be measured in the system. © Springer Science+Business Media, LLC 2010.