Tuesday, January 23, 2007

Delanceyplace.com 01/23/07-Mirror Neurons and Autism

In today's excerpt, mirror neurons and autism:

"John watches Mary, who is grasping a flower. John knows what Mary is doing and ... why she is doing it. ... The simple scene lasts just moments, and John's grasp of what is happening is nearly instantaneous. ... [H]ow exactly does he understand ... so effortlessly? A decade ago most neuroscientists and psychologists would have attributed an individual's understanding of someone else's actions and, especially, intentions to a rapid reasoning process not unlike that used to solve a logical problem ... [but] the ease and speed with which we typically understand simple actions suggest a much more straightforward explanation.

"In the early 1990s our research group at the University of Parma in Italy, which at the time included Luciano Fadiga, found that answer somewhat accidentally in a surprising class of neurons in the monkey brain that fire when an individual performs simple goal-directed motor actions, such as grasping a piece of fruit. The surprising part was that these same neurons also fire when the individual sees someone else perform the same act. Because this newly discovered subset of cells seemed to directly reflect acts performed by another in the observer's brain, we named them mirror neurons.

"We naturally wondered whether a mirror neuron system also exists in humans. ... Understanding the intentions of others is fundamental to human social behavior, and human mirror neurons appeared to confer that ability. ... We first obtained strong evidence that it does through a series of experiments that employed various techniques for detecting changes in motor cortex activity. ... [Further] our results also demonstrated ... that the mirror neuron system responded strongly to the intention component of an act.

"At first glance you might not notice anything odd on meeting a young boy with autism. But if you try to talk to him, it will quickly become obvious that something is seriously wrong. He may not make eye contact with you; ... More disconcerting, he may not be able to conduct anything remotely resembling a normal conversation ... he may lack genuine empathy for other people and be oblivious to subtle social cues that most children would pick up effortlessly. ...

"Because mirror neurons appeared to be involved in abilities such as empathy and the perception of another individual's intentions, it seemed logical to hypothesize that a dysfunction of the mirror neuron system could result in some of the symptoms of autism. Over the past decade, several studies have provided evidence for this theory."

Giacomo Rizzolatti, Leonardo Fogassi and Vittorio Gallese, "Mirrors in the Mind," Scientific American, November 2006, pp. 54-8; Vilayanur S. Ramachandran and Lindsay M. Oberman, “Broken Mirrors: A Theory of Autism," Scientific American, November 2006, pp. 63-4.

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