A Note on Mirror Neurons

This blog has not made much of a fuss about "mirror neurons," the name given to neurons that fire both when an individual does something and when the individual observes another individual do something. For example, a neuron might fire when a monkey reaches for a carrot and when the monkey sees another reach for a carrot. I have stayed away from discussing these nerves because it seemed to me the research hasn't gotton to the next stage: explaining how human mirror neurons differ functionally from monkey mirrors. Nevertheless, technical speculations about language evolution sometimes mention mirror neurons as critical to understanding actions and imitating them. So I was startled to see that in the latest issue of The Journal of Neuroscience (Oct. 29, 2008) there is a paper denying that humans even have mirror neurons. (Paper summary here.) So I suppose more time will have to pass before this blog reports on them.

Comments

[JoseAngel]

I wouldn't forget about them so quickly. Reflexive patterns in human perception must have a common basis with those of primates, which may well be found in mirror neurons, but there's no question that there have been new developments since. So the patterns of neuron activity need not be the same as those in monkeys. As you say, the differentia specifica is still elusive, but some kind of reflexive process (mirroring, if you want) is essential to human cognition, and also the the ability to manage complex symbols. And language.

[Robert V Sobczak]

Does this have any relation to toddlers repeating everything they hear from their parents or an older sibling ... almost in concert. It's hysterical ... but I wonder if there is a neurological undercurrent at work.

[JoseAngel]

Simply look at someone lifting their eyes and looking at you, or just look into a picture of a staring eye, and you'll feel the jolt of your mirror neurons. Looking at an eye is a perceptual experience very different from looking at any other object.
http://www.unizar.es/departamentos/filologia_inglesa/garciala/images/auge.jpg
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BLOGGER: You'll feel the jolt of something, but how do you know it is mirror neurons?

[JoseAngel]

It's a reflexive system which is especially sensitive to another's gaze. I suppose it's related to mirror neurons, though it's only a guess. It may well be working at the level of the firing patterns of neural groups, rather than in individual neurons. What needs to be explained, though, is the fact that there IS a jolt.

[Michael]

I think Greg Hickok's analysis of the results of this study is quite illuminating. Although he is an opponent of the mirror neuron hypothesis himself, he concludes that "if I've got the basics of the study correct (based on the abstract), this is not strong evidence against mirror neurons supporting action understanding. Neither is it evidence FOR mirror neurons, however."

http://talkingbrains.blogspot.com/2008/10/rock-paper-scissors-and-mirror-neurons.html

[Vijayachandra Ramachandra]

I think there is some "direct" evidence for the existence of the Mirror Neuron System in humans. Cytoarchitectonic studies (cellular composition of tissues) have revealed that the human analogue of monkeys’ F5 area is present in Brodmann’s area number 44 (Broca’s area). Please see- Rizzolatti & Arbib, 1998 for details.

However, one needs to be very cautious while interpreting results from research related to mirror neurons -especially neuroimaging and electrophysiological studies because they don't provide any direct evidence for the existence of this system in humans.