Evolving Mental Maps

Written by Science Knowledge on 2:19 AM

Researchers continue to probe the limits of the brain’s plasticity

We all carry in our heads various mental representations of our body—one example is the wellknown brain map of our sense of touch, sometimes called a homunculus (right). New studies show how such mental maps blur with age and readily extend to accommodate bionic limbs.

Blurred Bodies
As we age, our sense of touch becomes less accurate— some elderly people have a tough time reading Braille, for example. Looking for the roots of this sensory decline, German researchers at Ruhr University Bochum stumbled on a surprise: rather than shriveling up, the brain’s sensory body map—which helps us discriminate Braille letters by determining where the raised bumps are in relation to one another—expands with age, exactly as it does during learning. What could explain this paradox? The homunculus is made up of brain cells that represent our fingers, arms, and so on, loosely tracing a distorted human figurine along the cerebral cortex. In younger people the map stays sharp thanks to cells that dampen neural activity between areas representing different body parts. During aging, however, these cells presumably start to slack off; like an ink drawing that someone spills water on, the contours of the body map start to bleed. Luckily, studies show that a fuzzy old homunculus can be brought back into focus by stimulating the fingertips with a special apparatus, allowing at least some recovery of sensory precision.

Naturally Bionic
To the brain, electronic hardware is no different from flesh and blood, suggests a study at the University of California, Berkeley. In the experiment, monkeys learned to control a computer cursor—a stand-in for a bionic limb—through microelectrodes wiretapping their motor cortex. Although this feat is nothing new, the researchers showed for the first time that a stable memory of the new accessory had formed in the brain. During normal development, a baby learns to control its limbs by creating a mental map of the movable parts of its body—a motor homunculus of sorts. The new finding parallels that process, says neuroscientist Jose Carmena, who led the study, “but it’s about a prosthetic device, and that’s what is profound about it. We’re talking about an extension of your body’s schema.” In other words, once the brain-machine interface gets up to speed, our gray matter might already be set up to achieve effortless, plug-and-play-like control of electronic add-ons. —Frederik Joelving

Source of Information : Scientific American Mind November-December 2009

Related Posts by Categories

  1. 0 comments: Responses to “ Evolving Mental Maps ”

About Me

In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.

You are welcome to contact me and leave your comments in my Blog.

Science Knowledge

Want to subscribe?

Science Knowledge

Grab this Headline Animator

Enter your email address:

Delivered by FeedBurner