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Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

Cavallo A, Heyes C, Becchio C, Bird G, Catmur C - Soc Cogn Affect Neurosci (2013)

Bottom Line: In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse.Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse.By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development.

View Article: PubMed Central - PubMed

Affiliation: Università di Torino, Dipartimento di Psicologia, Centro di Scienza Cognitiva, Turin, Italy, All Souls College, University of Oxford, Oxford, OX1 4AL, UK, Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK, MRC Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Kings College London, London SE5 8AF, UK, and Department of Psychology, University of Surrey, Guildford GU2 7XH, UK.

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Experiment 1: Mean ± s.e.m. MEPs recorded from index and little finger muscles at five timepoints after observed action onset. For presentation purposes, MEP preference ratios are shown, calculated for each muscle as mean MEP size during observation of index finger actions divided by mean MEP size during observation of little finger actions. This ratio indicates the degree to which MEPs recorded in that muscle were greater for index than little finger action observation. A mirror effect is indicated by a higher value in the FDI (index finger muscle) than in the ADM (little finger muscle). All statistical analyses were applied to normalized MEP sizes. Significant mirror effects were found at 200, 250 and 300 ms.
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nst085-F2: Experiment 1: Mean ± s.e.m. MEPs recorded from index and little finger muscles at five timepoints after observed action onset. For presentation purposes, MEP preference ratios are shown, calculated for each muscle as mean MEP size during observation of index finger actions divided by mean MEP size during observation of little finger actions. This ratio indicates the degree to which MEPs recorded in that muscle were greater for index than little finger action observation. A mirror effect is indicated by a higher value in the FDI (index finger muscle) than in the ADM (little finger muscle). All statistical analyses were applied to normalized MEP sizes. Significant mirror effects were found at 200, 250 and 300 ms.

Mentions: The minimum number of MEPs in any cell was 10; an average of 11.7 ± 0.12 (s.d.) MEPs per cell were analysed. Raw MEP sizes are reported in Supplementary Table S1. For each muscle in every participant, mean normalized MEP sizes were calculated for each observation condition and TMS pulse timepoint (see Supplementary Table S2) and submitted to a 2 × 2 × 5 repeated-measures analysis of variance (ANOVA) with muscle (FDI and ADM), observed action (index and little finger abduction) and timepoint (100, 150, 200, 250 and 300 ms) as within-subjects factors. An interaction between muscle and observed action was obtained [F(1,13) = 6.903, P = 0.021], indicating a significant ‘mirror’ effect. However, the three-way interaction between muscle, observed action and timepoint was also statistically significant [F(4,52) = 2.804, P = 0.035], indicating that the mirror effect differed across timepoints. Simple interaction analyses were performed to test for the presence of a mirror effect (interaction between muscle and observed action) at each of the five timepoints. No mirror effect was obtained at timepoints of 100 and 150 ms after action onset; however, significant mirror effects were found for timepoints of 200, 250 and 300 ms [F(1,13) = 8.597, P = 0.012; F(1,13) = 5.381, P = 0.037; F(1,13) = 5.012, P = 0.043, respectively] illustrated in Figure 2. No other main effects or interactions reached significance.Fig. 2


Timecourse of mirror and counter-mirror effects measured with transcranial magnetic stimulation.

Cavallo A, Heyes C, Becchio C, Bird G, Catmur C - Soc Cogn Affect Neurosci (2013)

Experiment 1: Mean ± s.e.m. MEPs recorded from index and little finger muscles at five timepoints after observed action onset. For presentation purposes, MEP preference ratios are shown, calculated for each muscle as mean MEP size during observation of index finger actions divided by mean MEP size during observation of little finger actions. This ratio indicates the degree to which MEPs recorded in that muscle were greater for index than little finger action observation. A mirror effect is indicated by a higher value in the FDI (index finger muscle) than in the ADM (little finger muscle). All statistical analyses were applied to normalized MEP sizes. Significant mirror effects were found at 200, 250 and 300 ms.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4127010&req=5

nst085-F2: Experiment 1: Mean ± s.e.m. MEPs recorded from index and little finger muscles at five timepoints after observed action onset. For presentation purposes, MEP preference ratios are shown, calculated for each muscle as mean MEP size during observation of index finger actions divided by mean MEP size during observation of little finger actions. This ratio indicates the degree to which MEPs recorded in that muscle were greater for index than little finger action observation. A mirror effect is indicated by a higher value in the FDI (index finger muscle) than in the ADM (little finger muscle). All statistical analyses were applied to normalized MEP sizes. Significant mirror effects were found at 200, 250 and 300 ms.
Mentions: The minimum number of MEPs in any cell was 10; an average of 11.7 ± 0.12 (s.d.) MEPs per cell were analysed. Raw MEP sizes are reported in Supplementary Table S1. For each muscle in every participant, mean normalized MEP sizes were calculated for each observation condition and TMS pulse timepoint (see Supplementary Table S2) and submitted to a 2 × 2 × 5 repeated-measures analysis of variance (ANOVA) with muscle (FDI and ADM), observed action (index and little finger abduction) and timepoint (100, 150, 200, 250 and 300 ms) as within-subjects factors. An interaction between muscle and observed action was obtained [F(1,13) = 6.903, P = 0.021], indicating a significant ‘mirror’ effect. However, the three-way interaction between muscle, observed action and timepoint was also statistically significant [F(4,52) = 2.804, P = 0.035], indicating that the mirror effect differed across timepoints. Simple interaction analyses were performed to test for the presence of a mirror effect (interaction between muscle and observed action) at each of the five timepoints. No mirror effect was obtained at timepoints of 100 and 150 ms after action onset; however, significant mirror effects were found for timepoints of 200, 250 and 300 ms [F(1,13) = 8.597, P = 0.012; F(1,13) = 5.381, P = 0.037; F(1,13) = 5.012, P = 0.043, respectively] illustrated in Figure 2. No other main effects or interactions reached significance.Fig. 2

Bottom Line: In addition, it is unclear whether mirror and counter-mirror effects follow the same timecourse.Experiment 2 demonstrated significant effects of counter-mirror sensorimotor training at all timepoints at which a mirror response was found in Experiment 1 (i.e. from 200 ms onward), indicating that mirror and counter-mirror responses follow the same timecourse.By suggesting similarly direct routes for mirror and counter-mirror responses, these results support the associative account of mirror neuron origins whereby mirror responses arise as a result of correlated sensorimotor experience during development.

View Article: PubMed Central - PubMed

Affiliation: Università di Torino, Dipartimento di Psicologia, Centro di Scienza Cognitiva, Turin, Italy, All Souls College, University of Oxford, Oxford, OX1 4AL, UK, Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK, MRC Social, Genetic & Developmental Psychiatry Centre, Institute of Psychiatry, Kings College London, London SE5 8AF, UK, and Department of Psychology, University of Surrey, Guildford GU2 7XH, UK.

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