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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 2: mean ± s.e.m. MEPs recorded from index and little finger muscles before and after counter-mirror sensorimotor training, at three timepoints after observed action onset. MEP preference ratios are shown, where a higher value in the FDI than the ADM indicates a mirror effect, while the reverse pattern indicates a counter-mirror effect. A significant effect of training was found across all timepoints (A) and at each timepoint individually (B).
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nst085-F4: Experiment 2: mean ± s.e.m. MEPs recorded from index and little finger muscles before and after counter-mirror sensorimotor training, at three timepoints after observed action onset. MEP preference ratios are shown, where a higher value in the FDI than the ADM indicates a mirror effect, while the reverse pattern indicates a counter-mirror effect. A significant effect of training was found across all timepoints (A) and at each timepoint individually (B).

Mentions: The minimum number of MEPs in any cell was 12; an average of 18.03 ± 2.51 (s.d.) (pre-training) and 18.39 ± 2.46 (post-training) MEPs per cell were analysed. Raw MEP sizes are reported in Supplementary Table S3. For each muscle in every participant for both pre- and post-training sessions, mean normalized MEP sizes were calculated for each observation condition and TMS pulse timepoint (see Supplementary Table S4) and submitted to a 2 × 2 × 2 × 3 repeated-measures ANOVA with session (pre-training and post-training), muscle (FDI and ADM), observed action (index and little finger) and timepoint (200, 250 and 320 ms) as within-subjects factors. A significant mirror effect (interaction between muscle and observed action) was observed [F(1,17) = 8.864, P = 0.008]. However, this effect was modulated by the factor of testing session, yielding a significant three-way interaction between session, muscle and observed action [F(1,17) = 23.617, P < 0.001], indicating that counter-mirror training altered the mirror effect (Figure 4A). Crucially, the four-way interaction between session, muscle, observed action and timepoint was not statistically significant [F(2,34) = 0.332, P = 0.720]. This result implies that the effect of counter-mirror training was the same at all three timepoints. Confirming this conclusion, simple interaction analyses revealed a three-way interaction (session × muscle × observed action) at each timepoint [200 ms: F(1,17) = 6.476, P = 0.021; 250 ms: F(1,17) = 10.212, P = 0.005; 320 ms: F(1,17) = 7.496, P = 0.014; see Figure 4B].Fig. 4


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 2: mean ± s.e.m. MEPs recorded from index and little finger muscles before and after counter-mirror sensorimotor training, at three timepoints after observed action onset. MEP preference ratios are shown, where a higher value in the FDI than the ADM indicates a mirror effect, while the reverse pattern indicates a counter-mirror effect. A significant effect of training was found across all timepoints (A) and at each timepoint individually (B).
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Related In: Results  -  Collection

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nst085-F4: Experiment 2: mean ± s.e.m. MEPs recorded from index and little finger muscles before and after counter-mirror sensorimotor training, at three timepoints after observed action onset. MEP preference ratios are shown, where a higher value in the FDI than the ADM indicates a mirror effect, while the reverse pattern indicates a counter-mirror effect. A significant effect of training was found across all timepoints (A) and at each timepoint individually (B).
Mentions: The minimum number of MEPs in any cell was 12; an average of 18.03 ± 2.51 (s.d.) (pre-training) and 18.39 ± 2.46 (post-training) MEPs per cell were analysed. Raw MEP sizes are reported in Supplementary Table S3. For each muscle in every participant for both pre- and post-training sessions, mean normalized MEP sizes were calculated for each observation condition and TMS pulse timepoint (see Supplementary Table S4) and submitted to a 2 × 2 × 2 × 3 repeated-measures ANOVA with session (pre-training and post-training), muscle (FDI and ADM), observed action (index and little finger) and timepoint (200, 250 and 320 ms) as within-subjects factors. A significant mirror effect (interaction between muscle and observed action) was observed [F(1,17) = 8.864, P = 0.008]. However, this effect was modulated by the factor of testing session, yielding a significant three-way interaction between session, muscle and observed action [F(1,17) = 23.617, P < 0.001], indicating that counter-mirror training altered the mirror effect (Figure 4A). Crucially, the four-way interaction between session, muscle, observed action and timepoint was not statistically significant [F(2,34) = 0.332, P = 0.720]. This result implies that the effect of counter-mirror training was the same at all three timepoints. Confirming this conclusion, simple interaction analyses revealed a three-way interaction (session × muscle × observed action) at each timepoint [200 ms: F(1,17) = 6.476, P = 0.021; 250 ms: F(1,17) = 10.212, P = 0.005; 320 ms: F(1,17) = 7.496, P = 0.014; see Figure 4B].Fig. 4

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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