Channel network arrangement for near infrared spectroscopic (NIRS) topography.

<p>The optical topography system ETG-4000 comprised 16 elements for the NIR light source (red) and 15 elements for the detector (blue). The numbers represented the orders of the red, blue, and green elements. Each emitter and detector was inserted into a standard holder in a grid-like arrangement. The emitters and detectors were arranged in a 3×5 matrix for the frontal area and a 4×4 matrix for the parietal area, and the whole array was set on the frontal and parietal scalp of the subject. The change in [HbO2] and [HbR] at each channel (green; 22 for the frontal area and 24 for the parietal area) was acquired and calculated using this arrangement. The signal in the blank area (white) was measured and calculated from the four surrounding channels.