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[the human mirror neuron system... ]

Started by Textaris(txt*bot), April 22, 2008, 04:19:05 PM

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Quote[...] It is not normally possible to study single neurons in the human brain, so scientists can not be certain that humans have mirror neurons. However, the results of brain imaging experiments using fMRI have shown that the human inferior frontal cortex and superior parietal lobe is active when the person performs an action and also when the person sees another individual performing an action. Therefore, these brain regions are likely to contain mirror neurons and have been defined as the human mirror neuron system [19].

[...] Many studies link mirror neurons to understanding goals and intentions.

[...] Mirror neurons have been linked to empathy, because certain brain regions (in particular the anterior insula and inferior frontal cortex) are active when a person experiences an emotion (disgust, happiness, pain etc) and when they see another person experience an emotion.

[...] Some researchers claim there is a link between mirror neuron deficiency and autism.


[...] In Philosophy of mind, mirror neurons have become the primary rallying call of simulation theorists concerning our 'theory of mind.' 'Theory of mind' refers to our ability to infer another person's mental state (i.e., beliefs and desires) from their experiences or their behavior. For example, if you see a person reaching into a jar labelled 'cookies,' you might assume that he wants a cookie (even if you know the jar is empty) and that he believes there are cookies in the jar.

[...] One study reports stronger MEG responses related to the mirror neuron system in women compared to men [38]


[(38)Cheng, Y. W., Tzeng, O. J. L., Decety, J., Imada, T., Hsieh, J. C. 2006. Gender differences in the human mirror system: a magnetoencephalography study. Neuroreport. 2006 Jul 31;17(11):1115-9].



Source: http://en.wikipedia.org/wiki/Mirror_neuron (16 April 2008)

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Quote[...] When a paradigm-shattering discovery is made in science, it goes through three stages before gaining acceptance. First, people don't believe it; second, they claim it is of no interest; and third, they say that they have always known it. The discovery of mirror neurons in the early 1990s by Giacomo Rizzolatti, Vittorio Gallese, Marco Iacoboni and others, has been through all three stages. Happily, the idea seems to have emerged unscathed, judging from Mirrors in the Brain.

In their readable new book, Rizzolatti and philosopher of science Corrado Sinigaglia survey the growing field that the research has spawned, setting it in historical context. They begin with an overview of the neural circuits in the brain that are involved in simple goal-directed movements. When a monkey reaches for a fruit or puts something in its mouth, motor-command neurons in area F5 in the frontal lobes fire. Different neurons fire for different actions.

Rizzolatti discovered that some of these motor-command neurons fire even when a monkey just watches another monkey performing the same action. He called these cells mirror neurons.

[...]

Infants imitate their mother smiling or sticking out her tongue, implying a mirror-neuron-like computation for translating the visual appearance into the sequence of muscle twitches. Learning cannot be involved because the infant has never seen its own face. It is possible that the infant's smile is just a reflex that doesn't require elaborate translation. This can be ruled out if the newborn can also mimic an asymmetrical smile or a peculiar expression, which demands a sophisticated interfacing between visual appearance and motor output.

Mirror neurons may also have clinical relevance for phantom pain and stroke rehabilitation. If a mirror is propped up vertically on a table in front of a patient with, for example, a paralysed left hand (so that one edge of the mirror is against his chest), the patient gets the illusion that the left hand is moving when he moves his right hand. We and others have found that this causes recovery from paralysis, perhaps by visually reviving dormant mirror neurons.

Mirrors in the Brain documents how this new science has been received. Some psychologists have criticized the idea of mirror neurons as being reductionist. Others think it is a mere metaphor for what psychologists have long called the 'theory of mind module' — the ability of our brains to construct internal models of other people's minds to predict their behaviour. This criticism reveals a fear that neuroscience might displace psychology ('neuron envy'), and a misunderstanding of reductionism. It is a bit like saying that the complementarity of the two strands of DNA is a metaphor for the complementarity of offspring and parent.


From: "Reflecting on the mind" Vilayanur S. Ramachandran (Published online 16 April 2008)
BOOK REVIEWED-Mirrors in the Brain - by Giacomo Rizzolatti & Corrado Sinigaglia. Translated by Frances Anderson Oxford University Press
http://www.nature.com/nature/journal/v452/n7189/full/452814a.html