INTERACTIONS BETWEEN ELECTRICAL-ACTIVITY AND CORTICAL MICROCIRCULATION REVEALED BY IMAGING SPECTROSCOPY - IMPLICATIONS FOR FUNCTIONAL BRAINMAPPING

Modern neuroimaging techniques use signals originating from microcircu lation to map brain function. In this study, activity-dependent change s in oxyhemoglobin, deoxyhemoglobin, and light scattering were charact erized by an imaging spectroscopy approach that offers high spatial, t emporal, and spectral resolution. Sensory stimulation of cortical colu mns initiates tissue hypoxia and vascular responses that occur within the first 3 seconds and are highly localized to individual cortical co lumns. However, the later phase of the vascular response is less local ized, spreading over distances of 3 to 5 millimeters.