Functional optical coherence tomography reveals localized layer-specific activations in cat primary visual cortex in vivo.

Surface neural activity has been widely visualized using optical intrinsic signal imaging (OISI) from various cortical sensory areas. OISI of the cortical surface with a CCD camera gives integrated information across a depth of a few hundred micrometers. We visualize depth-resolved activation patterns of cat primary visual cortex by functional optical coherence tomography (fOCT). A comparison of the depth-integrated results of fOCT maps with the optical intrinsic signal profiles shows fairly good agreement. Our results reveal layer-specific activation patterns and indicate that the activation was not homogeneous.