Near-infrared detection of correlated activity in the brain

Summary form only. Near-ir light can pass trough the skull and reach the surface of the brain. It is well established in exposed cortex experiments that brain activity changes the brain surface optical properties in the near-ir, due both to changes in blood flow and to scattering from the brain cells. Several researches have proposed optical methods and the near-ir spectral region to measure brain function non-invasively with high temporal resolution and good localization. Our research has shown that it is possible to increase by at least one order of magnitude the detection of the small changes associated with neuronal activity. Our technical developments and a new sensor could make this optical technique widely available and complementary to fMRI.