Imaging the brain

Researchers at Stanford University have demonstrated a promising, minimally invasive optical technique that can capture micron-scale images from deep in the brains of live subjects.

The method, called two-photon microendoscopy, combines a pair of powerful optical and mechanical techniques into one device that fits in the palm of the hand.

Researchers want to image individual cells inside living subjects because it will give them insight into how cellular behaviour gives rise to the properties of organisms as a whole. For instance, the nerve cells of the hippocampus region of the brain give rise to important mental processes such as learning and memory.

Imaging living cells below the surface has been difficult to accomplish using conventional techniques. Electron microscopy can't be used on living tissue, and optical (light) microscopy can't penetrate very deeply into tissue because light scatters as it travels through tissue near the surface. Thus traditionally microscopic images of the living brain have only been made near the surface. Yet researchers would like to know more about certain deep-tissue areas of the brain, which are critical to understanding Alzheimer's and Parkinson's disease, for example.