Figure 3

The time line represents the change in HbO ₂ from quiet standing (before), during the task, and the return to a steady resting hemodynamic state after the completion of the task (after). HbO₂ level increases dramatically as a result of the challenging cognitive task during walking (red line). During usual-walking (blue line), levels of HbO₂ remained close to quiet standing levels. HbO₂ increased in the walking and counting condition (green line), however, there was a delayed response, suggesting that the task did not affect activation of the PFC. Standing+S7 (pink line) demonstrated a delayed HbO₂ decrease during the task. All measures returned towards pre-task values consistent with a hemodynamic response.