Figure 3.

Grand‐average changes in deoxyhemoglobin ([HHb]), oxyhemoglobin ([O₂Hb]), and total hemoglobin ([tHb]) concentrations as measured by NIRS over the left motor cortex in healthy young (n = 6, —•—) and elderly subjects (n = 5, —○—) during a 20‐sec contralateral finger‐tapping task. The individual changes were time‐locked averages over seven cycles of finger‐tapping. Data are presented as mean ± SD. P‐values representing the effect of time for both groups and P‐values representing the time‐by‐group interaction are shown (repeated‐measures ANOVA).