ABOVE: © istock.com, FIRSTSIGNAL
The mammalian brain consists of billions of neurons wired together in various circuits, each one involved in specific physiological functions. To better understand how these different neurons and circuits are associated with mental activities and diseases, researchers are reconstructing detailed, three-dimensional maps of neural networks.
However, 3-D imaging of the mammalian brain is challenging. Light scatters as it travels through layers of tissue, dispersed by a variety of molecules such as water, lipids, and proteins. This reduces image resolution.
One way to improve resolution is to reduce the scattering. Researchers achieve this by first removing water and lipids from tissue. Next, chemicals are introduced that have a refractive index—a measure of how much the molecules bend light that passes through them—in the range of that of proteins. Establishing near-homogenous refractive indices in the molecules that populate the tissue environment allows light rays to converge to improve ...