Tuesday, September 21, 2010

More problems for mirror neurons

A recent paper in Human Brain Mapping by Molenberghs et al. challenges the view that the motor system is the basis for action understanding and instead implicates, surprise-surprise, a sensory region the superior temporal sulcus. The abstract from this report (see below) provides a nice summary. I know what the response from the MN crowd will be though: the STS must be part of the mirror system!

It has been suggested that in humans the mirror neuron system provides a neural substrate for imitation behaviour, but the relative contributions of different brain regions to the imitation of manual actions is still a matter of debate. To investigate the role of the mirror neuron system in imitation we used fMRI to examine patterns of neural activity under four different conditions: passive observation of a pantomimed action (e.g., hammering a nail); (2) imitation of an observed action; (3) execution of an action in response to a word cue; and (4) self-selected execution of an action. A network of cortical areas, including the left supramarginal gyrus, left superior parietal lobule, left dorsal premotor area and bilateral superior temporal sulcus (STS), was significantly active across all four conditions. Crucially, within this network the STS bilaterally was the only region in which activity was significantly greater for action imitation than for the passive observation and execution conditions. We suggest that the role of the STS in imitation is not merely to passively register observed biological motion, but rather to actively represent visuomotor correspondences between one's own actions and the actions of others.

Molenberghs P, Brander C, Mattingley JB, & Cunnington R (2010). The role of the superior temporal sulcus and the mirror neuron system in imitation. Human brain mapping, 31 (9), 1316-26 PMID: 20087840

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