FIRST GLIMPSE / A BETTER LOOK / COMPUTERIZED VISIONS [ THE AMAGING BRAIN ]

FIRST GLIMPSE

The first technology to peer into the brain was the x-ray, invented by Wilhelm Rontgen (1845-1923) in 1895. The German scientist discovered a form of radiation that could penetrate the body; the rays were absorbed by dense bones, which then appeared as shadows on film.

When applied to the brain, simple x-rays, harnessed to make photographic images of bone, permitted doctors to make a basic examination of the structure of the head. However, x-rays give only a two-dimensional view, and show relatively little of the soft tissues of organs. As the human brain is a three-dimensional object, whatever appeared in a 2-D image usually was murky and confusing. Often, structures lying in different planes of the brain overlapped each other, making analysis difficult.

A BETTER LOOK

Scientists first peered at real-time brain functions in 1929 with the invention of the electroencephalogram, or EEG. Electrodes fitted to the scalp record electrical activity within the brain as neurons discharge. Unusual brainwave activity registered on an EEG may indicate brain disorders. This technique records electrical activity in real time.

More recently, scientists have employed a variety of tools to get a more detailed and localized look at structure and action inside the brain.

COMPUTERIZED VISIONS

Computerized axial tomograms, or CT scans, have substantially improved the ability of x-rays to probe the secrets of the brain. A patient receiving a CT scan lies inside a doughnut-shaped array of sensitive detectors while a movable x-ray emitter rotates around the brain. Computers convert the images into a three-dimensional image of the brain. Slices of the interior-the word tomos is Greek for “section”-can be teased from the data and shown on a screen to give doctors a narrow look at particular points in the brain. For example, a CT scan might reveal a tumor located deep inside the tissue of a living brain, far too deep to be visible during routine exploratory surgery.

SWEDISH SCIENTISTS in 2008 created the illusion of shaking hands with yourself. They had volunteers and a mannequin wear virtual reality goggles Images in the volunteers’ goggles came from the dummy. Most test subjects felt the weird sensation of the dummy’s point of view when shaking their own hands.