Wednesday, October 24, 2007

Cells that read minds

Cells That Read Minds Leigh Wells MONKEY SEE When a monkey watches a researcher bring an object—an ice cream cone, for example— to his mouth, the same brain neurons fire as when the monkey brings a peanut to its own mouth. In the early 1990's, Italian researchers discovered this phenomenon and named the cells "mirror neurons." More Photos > Sign In to E-Mail This Printer-Friendly Single-Page Reprints Save Article By SANDRA BLAKESLEE Published: January 10, 2006 On a hot summer day 15 years ago in Parma, Italy, a monkey sat in a special laboratory chair waiting for researchers to return from lunch. Thin wires had been implanted in the region of its brain involved in planning and carrying out movements. Cells That Read Minds Every time the monkey grasped and moved an object, some cells in that brain region would fire, and a monitor would register a sound: brrrrrip, brrrrrip, brrrrrip. A graduate student entered the lab with an ice cream cone in his hand. The monkey stared at him. Then, something amazing happened: when the student raised the cone to his lips, the monitor sounded - brrrrrip, brrrrrip, brrrrrip - even though the monkey had not moved but had simply observed the student grasping the cone and moving it to his mouth. The researchers, led by Giacomo Rizzolatti, a neuroscientist at the University of Parma, had earlier noticed the same strange phenomenon with peanuts. The same brain cells fired when the monkey watched humans or other monkeys bring peanuts to their mouths as when the monkey itself brought a peanut to its mouth. Later, the scientists found cells that fired when the monkey broke open a peanut or heard someone break a peanut. The same thing happened with bananas, raisins and all kinds of other objects. "It took us several years to believe what we were seeing," Dr. Rizzolatti said in a recent interview. The monkey brain contains a special class of cells, called mirror neurons, that fire when the animal sees or hears an action and when the animal carries out the same action on its own. But if the findings, published in 1996, surprised most scientists, recent research has left them flabbergasted. Humans, it turns out, have mirror neurons that are far smarter, more flexible and more highly evolved than any of those found in monkeys, a fact that scientists say reflects the evolution of humans' sophisticated social abilities. The human brain has multiple mirror neuron systems that specialize in carrying out and understanding not just the actions of others but their intentions, the social meaning of their behavior and their emotions. "We are exquisitely social creatures," Dr. Rizzolatti said. "Our survival depends on understanding the actions, intentions and emotions of others." He continued, "Mirror neurons allow us to grasp the minds of others not through conceptual reasoning but through direct simulation. By feeling, not by thinking." The discovery is shaking up numerous scientific disciplines, shifting the understanding of culture, empathy, philosophy, language, imitation, autism and psychotherapy. Everyday experiences are also being viewed in a new light. Mirror neurons reveal how children learn, why people respond to certain types of sports, dance, music and art, why watching media violence may be harmful and why many men like pornography. How can a single mirror neuron or system of mirror neurons be so incredibly smart? Most nerve cells in the brain are comparatively pedestrian. Many specialize in detecting ordinary features of the outside world. Some fire when they encounter a horizontal line while others are dedicated to vertical lines. Others detect a single frequency of sound or a direction of movement. Moving to higher levels of the brain, scientists find groups of neurons that detect far more complex features like faces, hands or expressive body language. Still other neurons help the body plan movements and assume complex postures. Mirror neurons make these complex cells look like numbskulls. Found in several areas of the brain - including the premotor cortex, the posterior parietal lobe, the superior temporal sulcus and the insula - they fire in response to chains of actions linked to intentions. Studies show that some mirror neurons fire when a person reaches for a glass or watches someone else reach for a glass; others fire when the person puts the glass down and still others fire when the person reaches for a toothbrush and so on. They respond when someone kicks a ball, sees a ball being kicked, hears a ball being kicked and says or hears the word "kick." "When you see me perform an action - such as picking up a baseball - you automatically simulate the action in your own brain," said Dr. Marco Iacoboni, a neuroscientist at the University of California, Los Angeles, who studies mirror neurons. "Circuits in your brain, which we do not yet entirely understand, inhibit you from moving while you simulate," he said. "But you understand my action because you have in your brain a template for that action based on your own movements. 1 2 3 Next Page > More Articles in Science > Ads by Google what's this? Alzheimer's Prevention Expert brain health tips & studies from the Alzheimer’s Association www.alz.org How to Do Eye Exercise Eye Exercise Program that Works! See Results in Only Minutes a Day. Program-for-Better-Vision.com/Eye Keep Your Brain Sharp Mental workouts keep the aging brain functioning. RLTV www.rl.tv Related Articles SIDE EFFECTS; This Is Your Brain on Schadenfreude. Do You Feel Bad About Feeling Good? 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