Fig. 2.
fNIRS timeline. Each patient has one of their knees operated on [as shown in (a)59]. Using the fNIRS cap in (b), concentration readings are obtained from the 24 nodes attached to the head. These nodes observe four concentrations in the six ROIs shown in (c) (a, superior S1; b, central S1; c, inferior S1; d, lateral frontal cortex; e, lateral polar frontal cortex; f, mPFC). As the opposite cortex is observed and since the right knee is operated on, we look at the 12 channels in the left cortex (7 to 12 in the frontal PreFC and 19 to 24 in the rear in Fig. 1). and HbR are recorded for 25-min after surgery starts [see (d) for the average oxyhemoglobin of the six relevant filtered channels for PreFC and S1, with the standard error represented each side of the error bars]. An incision was performed at the start of the section of time marked in black and continued through the black bar’s duration. A sliding window of 10 s in 1 s increments was then calculated for the minute after the incision. This period of time is then examined for trends in the patient (no nerve block was administered to this patient). When all the patient data have been collected, the average oxygenated hemoglobin of the patients who did receive nerve block and those who did not were calculated and plotted along with a running error bar over time as shown in (e).