Fig. 2.

An example calculation of the interhemispheric correlation coefficients (IHCC) is shown in a control and stroke subject. The change in optical density (ΔOD) at 830 nm for a healthy control (top) and a stroke subject (bottom) are shown after data filtering in the cardiac (0.7–3 Hz, left) and the respiratory (0.15–0.7 Hz, right) frequency bands. Note the different time scales. For simplicity, only two channels are presented for each hemisphere. The corresponding IHCCs are shown in the boxes