Fig. 4.

Changes from baseline in deoxygenated hemoglobin (HbR) concentration due to cognitive tasks in patients with bipolar disorders (□) and normal controls (■). Values are means, with standard deviations represented by vertical bars. LF, Letter fluency task; CF, category fluency task; LCT, letter cancellation test; RCPM-A, Set A of Raven’s Colored Progressive Matrices; RCPM-B, Set B of Raven’s Colored Progressive Matrices. * Post hoc analysis following a group × task × hemisphere analysis of variance on HbR concentration revealed that both groups showed a greater increase in HbR concentration in the LCT compared with the other tasks (p<0.005). Note that the graph indicates net increases of Hb concentration from a baseline value (ΔHb concentration) and not changes in the absolute value of Hb concentration in the scanned region. ΔHb concentration showed modest increases by cognitive activation when compared with apparently large between-subjects differences of Hb