COMBINE NIRS AND FMRI TO INVESTIGATE HEMODYNAMIC RESPONSE TO TRANSIENT ACTIVATION AND DEACTIVATION

We used transcranial near-infrared spectroscopy (NIRS) and fMRI at 3T to investigate both positive and negative BOLD effects in human brain activation. Using NIRS we recorded concentration changes in both oxy- and deoxy- as well as total hemoglobin levels by measuring changes of absorption at two different wavelengths in brain in response to both transient activations and deactivations. Similar experiments were also performed using fMRI. In addition to different nonlinear BOLD responses to activation and deactivation, we also investigated the relationship between NIRS and fMRI data