Above image: Jim Peters almost wins the marathon Vancouver, 7 August 1954, with mirror neurons by Rizzolatti & Craighero (2004).
Greg Hickok at Talking Brains has a series of posts dismantling the mirror neuron theory of action understanding. Actually, he lets one of the leading researchers in the field, Giacomo Rizzolatti [and his coauthor] dismantle the theory himself in a recent review paper (Rizzolatti & Sinigaglia, 2010). Greg points out the inconsistencies in the NRN article...
So, mirror neurons, those cells that fire during specific actions such as grasping-with-the-hand and while watching the same specific action -- the very cells that got everyone SO excited -- are not involved in action understanding. Rather, according to R&S, action understanding is achieved by cells that do not code for actions at all, but something higher level, goals/intentions....and also the problems with promoting an unfalsifiable theory:
It's worth noting that R&S directly contradict themselves in the sidebar definition of "Mirror-based action understanding":The comprehension of an observed action based on the activation of a motor programme in the observer’s brain. p. 265
A motor program presumably controls a specific action, such as grasping-with-the-hand, not an action-independent goal or intention.
I think the mirror neuron folks have a serious problem on their hands: there is apparently no empirical result that can falsify the theory. If a mirror neuron shows up in an unexpected place, it is a new part of the mirror system. If a mirror neuron's activity dissociates from action understanding, it was not coding understanding at that moment. If damage to the motor system doesn't disrupt understanding, it is because that part of the motor system isn't mirroring.As another long-time mirror neuron skeptic, I highly recommend this series:
Mirror Neurons - The unfalsifiable theory
Mirror neurons support action understanding -- "from the inside"?
Self-destruction of the mirror neuron theory of action understanding
Reference
Rizzolatti, G. & Sinigaglia, C. (2010). The functional role of the parieto-frontal mirror circuit: interpretations and misinterpretations. Nature Reviews Neuroscience, 11 (4), 264-274.
“Mirror neurons” may be headed for the cutting room floor of neuroscience as Talking Brain suggests, but the underlying discovery at the Rizzolatti lab remains significant: motor-cognitive correlation at a neuronal level, commensurate activation.
ReplyDeletePassive observation is the condition which fired the neurons. The lab extensively ruled out simple motor involvement, such as in active imitation and response suppression (motor activity is the speciality of this group). Passive observation remained.
Too bad the Rizzolatti group wasted a couple of decades by touting a magical new type of neuron (“mirror!”) as their finding, rather than the motor-cognitive link itself. In their defense, their lab had been busy finding new neurons, so this looked like the newest and best one yet.
Passive observation is evidently cognitive, involving the recognition of a meaningful event (unified concept) by a parallel organism (“conspecific” if primates are the species).
So passive observation means theory of mind or something like it: ego differentiation, social contextualization, pragmatic orientation. All these, arguably cognitive functions.
Rizzolatti fans should refocus their mindset and machinery, to the cognitive links in the animals they study. This is evidence from biology for embodied neuroscience, as Liz Bates said.
Wait! Let’s rescue MNs and their magical name. The critical study will be: “The P600 of the Mirror Neuron: cognitive analysis in the motor system”. Who’s up for it?
Still, mirror neurons must do something, whether or not they explain action understanding, so I'm cautiously optimistic that they'll lead to interesting advances.
ReplyDeleteI agree with the previous comment, I hope their are interesting further advances in this field.
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