FIGURE 6.

Qualitative data analysis of mean O₂Hb amplitudes in left prefrontal channels over the course of eight NIRS based neurofeedback sessions in one exemplary participant (subject #6) out of two that were able to voluntarily up-regulate activity over the whole training course, but in only two neighboring prefrontal channels at a time (bold lines representing channels #8 and 9 for the first session, #4 and 9 for the second session and #4 and 8 for the remaining sessions). These pairs of channels exhibit more pronounced positive amplitudes as compared to the other frontal ROI channels. Changes in O₂Hb concentration occurred over virtually identically located neighboring channels in both hemispheres. The part shaded in gray represents the regulation phase of 30 s duration.