Figure 3 Time course (x-axis) of the hemodynamic responses in reading aloud for irregular words (A) and nonwords (B) for one female participant (F. M.). The y-axis indicates relative changes in concentration (from −1 × 10−06 to 5 × … For this participant (F. M.), [HbO] and [HbT] values increased immediately after initiating

the reading task, and gradually reached their peak at about 6 sec in the occipital regions bilaterally. In the frontotemporal regions bilaterally, [HbO] and [HbT] reached their peak concentrations at around 17 sec. When the participant stopped reading, [HbO] Inhibitors,research,lifescience,medical and [HbT] levels showed a rapid decline and gradually returned to their baseline. This pattern of increase was sustained for [HbR] albeit with a much smaller amplitude than [HbO]. Inhibitors,research,lifescience,medical We also found that [HbO] concentrations were higher in the left than the right hemisphere in the frontotemporal regions. Hemodynamic changes were analogous for irregular word and nonword reading.

All participants showed similar patterns of hemodynamic responses except for B. B., who showed the reverse pattern. In this participant, we recorded a Inhibitors,research,lifescience,medical decrease in [HbO] and an increase in [HbR] concentrations in all regions but the bilateral occipital regions. We observed Inhibitors,research,lifescience,medical in another participant (J. T.) a right lateralization of reading in the frontotemporal regions with higher [HbO] concentrations in the right than the left hemisphere, for both irregular words and nonwords. In irregular word reading, we found that the maximum peak of activation for [HbO] in all

12 participants occurred at about 8 sec in the bilateral occipital Inhibitors,research,lifescience,medical selleck kinase inhibitor cortices, at about 12 sec in the bilateral temporal regions, and finally at about 14.5 sec in the bilateral frontal regions. In nonword reading, the maximum peak of activation we observed for the 12 participants occurred also at approximately 8 sec in the bilateral occipital cortices, but at about 13 sec in the bilateral frontal regions and approximately 14 sec in the bilateral temporal regions, in contrast with irregular word reading. Spatial distribution of the significant hemodynamic responses We performed a two-tailed paired t-test Electron transport chain for each participant (t(12) > 2.17, P < 0.05, uncorrected) to determine the cerebral regions in which [HbT] concentrations in reading tasks were significantly different from those measured at rest (10-sec duration before the beginning of the reading tasks). [HbT] was chosen as the dependent variable because it correlates with cerebral blood flow. The regions were fitted on a segmented Brodmann Atlas template.