Fig. 7.

Physiological validation using a breath-holding test. A) Complete session data. The solid red lines represent OxyHb, dashed black lines are DeoxyHb, and shaded gray areas represents breath-holding periods. Characteristic dips and recovery in OxyHb are visible in these data. B thru E) Block median with highlighted standard error of the median of 10 cycles measuring the change in baseline measurement with respect to the 10 s preceding the breath-holding period. An increase in source-detector separation results in deeper imaging into the head F) A segment of raw, unprocessed data from our fNIRS device during 850-nm LED light input is shown. Arterial pulsations are visible in the figure. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)