dr. rizzolatti also showed some new evidence that suggests autistic children have an underactivated mirror neuron system, perhaps suggesting a reason for their typical lack of empathy or social learning behaviours. when measuring the muscle activation (via EMG, or electromyography) of the mylohyoid (MH) muscle - the muscle that opens our mouths - in typically-developing and autistic children, an incredible observation was made: when observing another person move an object, the MH muscle in both groups of children did not elicit any EMG activity --> no surprise, as moving an object doesn't require us to open our mouths. however, when observing another person eat the same object, typically-developing children showed marked EMG activation of the MH muscle, while autistic children showed none.
this system not only allows us to observe, encode, and physically replicate behaviours, but also elicits cortical activation when simply viewing a familiar behavior. just another amazing property of the sophisticated network that underlies our perception & interaction of the world around us, lending empirical and quantifiable merit to the common anecdote "monkey see, monkey do".
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| Dr. Giacomo Rizzolatti, Friday March 18, 2011 at the Robert McEwan Auditorium, Schulich School of Business, York University, Toronto. |
last friday (march 18th) was a very exciting day at York U as we were honoured to have a guest lecture by none other than Dr. Giacomo Rizzolatti, founder of the mirror neuron system, which essentially allows us (including humans, monkeys, and other small mammals and birds) to perceive a behaviour and compute it into a motor behaviour. this isn't the same thing as mimicry, but facilitates a form of learning that is encoded in visual systems that is also activated when we see person performing an act that we are capable of performing. in his talk, dr. rizzolatti mentioned that babies that cannot walk do not show activation of the mirror neuron system until they learn how to walk; once they do, seeing another person walk activates this system. similarly, professional dancers (or ballet and capoeira) similarly activate their mirror neuron system when watching others perform the intricate dances they are proficient at (i.e., ballet --> ballet), but not to the other (ballet does not activate the mirror neurons of capoeira pros). mirror neurons also exist in birds, as activations have been shown when listening to familiar birdsongs. this is an amazing implication: a common neural system exists across species, and perhaps first developed in a common ancestor species.
dr. rizzolatti also showed some new evidence that suggests autistic children have an underactivated mirror neuron system, perhaps suggesting a reason for their typical lack of empathy or social learning behaviours. when measuring the muscle activation (via EMG, or electromyography) of the mylohyoid (MH) muscle - the muscle that opens our mouths - in typically-developing and autistic children, an incredible observation was made: when observing another person move an object, the MH muscle in both groups of children did not elicit any EMG activity --> no surprise, as moving an object doesn't require us to open our mouths. however, when observing another person eat the same object, typically-developing children showed marked EMG activation of the MH muscle, while autistic children showed none.
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| From Rizzolatti et al. (2007). Impairment of actions chains in autism and its possible role in intention understanding. PNAS, 104 (45), 17825-30. |
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