In vivo Near Infrared Spectroscopy: a novel approach for simultaneously estimating molecules and hemodynamic parameters in the human and rat brain: a review

Abstract

There have been great advances in optical brain imaging over the last 50 years and the technique has grown into a richly diverse field. In vivo recording and imaging using light provides extraordinary sensitivity to functional changes through intrinsic contrast, blood, and can even exploit the growing availability of exogenous optical contrast agents. Light can be used to analyze microscopic structures and function in vivo in the exposed animal brain, while also allowing noninvasive imaging of hemodynamics and metabolism in a clinical setting. This review is an overview of approaches that have been applied in vivo optical brain recording, in both animals and humans. The basic principles of each technique are described, emphasizing the techniques used in our laboratory. Techniques include imaging of exposed cortex, in vivo functional spectroscopy of the living brain using optic fibers, and the broad range of noninvasive topography and tomography approaches to near-infrared imaging of the human brain. The basic principles of each technique are described, followed by examples of current applications to cutting-edge neuroscience research. In summary, it is shown that optical brain recording continues to grow and evolve, embracing new technologies and advancing to address ever more complex and important neuroscientific questions.