Mu suppression - a good measure of the human mirror neuron system?
<p>Mu suppression has been proposed as a signature of the activity of the human mirror neuron system. However the mu frequency band (8-13 Hz) overlaps with the alpha frequency band, which is sensitive to attentional fluctuation, and thus mu suppression could potentially be confounded by change...
| Main Authors: | , |
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| Format: | Journal article |
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Elsevier
2016
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| _version_ | 1797102415415083008 |
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| author | Hobson, H Bishop, D |
| author_facet | Hobson, H Bishop, D |
| author_sort | Hobson, H |
| collection | OXFORD |
| description | <p>Mu suppression has been proposed as a signature of the activity of the human mirror neuron system. However the mu frequency band (8-13 Hz) overlaps with the alpha frequency band, which is sensitive to attentional fluctuation, and thus mu suppression could potentially be confounded by changes in attentional engagement. The specific baseline against which mu suppression is assessed may be crucial, yet there is little consistency in how this is defined. We examined mu suppression in 61 typical adults, the largest mu suppression study so far conducted. We compared different methods of baselining, and examined activity at central and occipital electrodes, to both biological (hands) and non-biological (kaleidoscope) moving stimuli, to investigate the involvement of attention and alpha activity in mu suppression. We also examined changes in beta power, another candidate index of mirror neuron system engagement. We observed strong mu suppression restricted to central electrodes when participants performed hand movements, demonstrating that mu is indeed responsive to the activity of the motor cortex. However, when we looked for a similar signature of mu suppression to passively observed stimuli, the baselining method proved to be crucial. Selective suppression for biological vs non-biological stimuli was seen at central electrodes only when we used a within-trial baseline based on a static stimulus: this method greatly reduced trial-by-trial variation in the suppression measure compared with baselines based on blank trials presented in separate blocks. Even in this optimal condition, 16-21% of participants showed no mu suppression. Changes in beta power also did not match our predicted pattern for mirror neuron system engagement, and did not seem to offer a better measure than mu. Our conclusions are in contrast to those of a recent meta-analysis, which concluded that mu suppression is a valid means to examine mirror neuron activity. We argue that mu suppression can be used to index the human mirror neuron system, but the effect is weak and unreliable and easily confounded with alpha suppression.</p> |
| first_indexed | 2024-03-07T06:05:42Z |
| format | Journal article |
| id | oxford-uuid:edc2a5ce-df0d-4a90-8b8b-f52a705efe7e |
| institution | University of Oxford |
| last_indexed | 2024-03-07T06:05:42Z |
| publishDate | 2016 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | oxford-uuid:edc2a5ce-df0d-4a90-8b8b-f52a705efe7e2022-03-27T11:27:36ZMu suppression - a good measure of the human mirror neuron system?Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:edc2a5ce-df0d-4a90-8b8b-f52a705efe7eSymplectic Elements at OxfordElsevier2016Hobson, HBishop, D<p>Mu suppression has been proposed as a signature of the activity of the human mirror neuron system. However the mu frequency band (8-13 Hz) overlaps with the alpha frequency band, which is sensitive to attentional fluctuation, and thus mu suppression could potentially be confounded by changes in attentional engagement. The specific baseline against which mu suppression is assessed may be crucial, yet there is little consistency in how this is defined. We examined mu suppression in 61 typical adults, the largest mu suppression study so far conducted. We compared different methods of baselining, and examined activity at central and occipital electrodes, to both biological (hands) and non-biological (kaleidoscope) moving stimuli, to investigate the involvement of attention and alpha activity in mu suppression. We also examined changes in beta power, another candidate index of mirror neuron system engagement. We observed strong mu suppression restricted to central electrodes when participants performed hand movements, demonstrating that mu is indeed responsive to the activity of the motor cortex. However, when we looked for a similar signature of mu suppression to passively observed stimuli, the baselining method proved to be crucial. Selective suppression for biological vs non-biological stimuli was seen at central electrodes only when we used a within-trial baseline based on a static stimulus: this method greatly reduced trial-by-trial variation in the suppression measure compared with baselines based on blank trials presented in separate blocks. Even in this optimal condition, 16-21% of participants showed no mu suppression. Changes in beta power also did not match our predicted pattern for mirror neuron system engagement, and did not seem to offer a better measure than mu. Our conclusions are in contrast to those of a recent meta-analysis, which concluded that mu suppression is a valid means to examine mirror neuron activity. We argue that mu suppression can be used to index the human mirror neuron system, but the effect is weak and unreliable and easily confounded with alpha suppression.</p> |
| spellingShingle | Hobson, H Bishop, D Mu suppression - a good measure of the human mirror neuron system? |
| title | Mu suppression - a good measure of the human mirror neuron system? |
| title_full | Mu suppression - a good measure of the human mirror neuron system? |
| title_fullStr | Mu suppression - a good measure of the human mirror neuron system? |
| title_full_unstemmed | Mu suppression - a good measure of the human mirror neuron system? |
| title_short | Mu suppression - a good measure of the human mirror neuron system? |
| title_sort | mu suppression a good measure of the human mirror neuron system |
| work_keys_str_mv | AT hobsonh musuppressionagoodmeasureofthehumanmirrorneuronsystem AT bishopd musuppressionagoodmeasureofthehumanmirrorneuronsystem |