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Long-latency TMS-evoked potentials during motor execution and inhibition.

Yamanaka K, Kadota H, Nozaki D - Front Hum Neurosci (2013)

Bottom Line: Transcranial magnetic stimulation (TMS) has often been used in conjunction with electroencephalography (EEG), which is effective for the direct demonstration of cortical reactivity and corticocortical connectivity during cognitive tasks through the spatio-temporal pattern of long-latency TMS-evoked potentials (TEPs).However, it remains unclear what pattern is associated with the inhibition of a planned motor response.TEPs related to motor execution and inhibition were obtained by subtractions between averaged EEG waveforms with and without TMS.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Human Life Sciences, Showa Women's University Tokyo, Japan.

ABSTRACT
Transcranial magnetic stimulation (TMS) has often been used in conjunction with electroencephalography (EEG), which is effective for the direct demonstration of cortical reactivity and corticocortical connectivity during cognitive tasks through the spatio-temporal pattern of long-latency TMS-evoked potentials (TEPs). However, it remains unclear what pattern is associated with the inhibition of a planned motor response. Therefore, we performed TMS-EEG recording during a go/stop task, in which participants were instructed to click a computer mouse with a right index finger when an indicator that was moving with a constant velocity reached a target (go trial) or to avoid the click when the indicator randomly stopped just before it reached the target (stop trial). Single-pulse TMS to the left (contralateral) or right (ipsilateral) motor cortex was applied 500 ms before or just at the target time. TEPs related to motor execution and inhibition were obtained by subtractions between averaged EEG waveforms with and without TMS. As a result, in TEPs induced by both contralateral and ipsilateral TMS, small oscillations were followed by a prominent negative deflection around the TMS site peaking at approximately 100 ms post-TMS (N100), and a less pronounced later positive component (LPC) over the broad areas that was centered at the midline-central site in both go and stop trials. However, compared to the pattern in go and stop trials with TMS at 500 ms before the target time, N100 and LPC were differently modulated in the go and stop trials with TMS just at the target time. The amplitudes of both N100 and LPC decreased in go trials, while the amplitude of LPC decreased and the latency of LPC was delayed in both go and stop trials. These results suggested that TMS-induced neuronal reactions in the motor cortex and subsequent their propagation to surrounding cortical areas might change functionally according to task demand when executing and inhibiting a motor response.

No MeSH data available.


Related in: MedlinePlus

Artifact rejection from TMS-EEG data by using independent component analysis in a typical participant. (A) Averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) recorded from 61 surface electrodes. (B) Averaged independent component (IC) waveforms and their projection maps in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) extracted from 61 EEG waveforms. In order of their variance size, the largest component (IC1), fifth largest component (IC5), and ninth largest component (IC9) were selectively shown. (C) Artifact-removed averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels).
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FA1: Artifact rejection from TMS-EEG data by using independent component analysis in a typical participant. (A) Averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) recorded from 61 surface electrodes. (B) Averaged independent component (IC) waveforms and their projection maps in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) extracted from 61 EEG waveforms. In order of their variance size, the largest component (IC1), fifth largest component (IC5), and ninth largest component (IC9) were selectively shown. (C) Artifact-removed averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels).

Mentions: The data from the 61-channel scalp EEG (and 1-channel eye-related potential) in all conditions were first segmented in epochs from 1,500 ms before and 1,000 ms after the target time, and all of the segmented data was bunched together for each subject. Next, an independent component (IC) analysis with extended infomax algorithm (Bell and Sejnowski, 1995; Lee et al., 1999) was applied to the EEG data in order to identify and remove the components reflecting TMS-related artifacts and eye-blink- and/or eye-movement-related activities (Jung et al., 2000a,b; Johnson et al., 2012). From the 62 extracted independent components (ICs), the TMS-related ICs were chosen mainly by their time courses; the variance value of the IC during a time period of 20 ms just after the TMS was 20 times larger than those during the rest of the time periods and during no-TMS trials. The results suggested that such ICs impulsively induced huge potentials only when the TMS pulse was delivered. Eye-blink- and eye-movement-related activities were also determined by the time courses, which indicated their inactivation during a task, and scalp topographies of the projection maps, which provided their origin on the edge of anterior sites. Based on these criteria, we could effectively remove TMS-related [11.4 ± 2.7 (mean ± SD for all participants)], eye-blink-related (1 ± 0), and eye-movement-related (0.8 ± 0.4) components and obtain EEG waveforms with little distortion, at least during the time period with two large long-latency TEP components (see Figure A1 in Appendix).


Long-latency TMS-evoked potentials during motor execution and inhibition.

Yamanaka K, Kadota H, Nozaki D - Front Hum Neurosci (2013)

Artifact rejection from TMS-EEG data by using independent component analysis in a typical participant. (A) Averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) recorded from 61 surface electrodes. (B) Averaged independent component (IC) waveforms and their projection maps in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) extracted from 61 EEG waveforms. In order of their variance size, the largest component (IC1), fifth largest component (IC5), and ninth largest component (IC9) were selectively shown. (C) Artifact-removed averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824362&req=5

FA1: Artifact rejection from TMS-EEG data by using independent component analysis in a typical participant. (A) Averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) recorded from 61 surface electrodes. (B) Averaged independent component (IC) waveforms and their projection maps in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels) extracted from 61 EEG waveforms. In order of their variance size, the largest component (IC1), fifth largest component (IC5), and ninth largest component (IC9) were selectively shown. (C) Artifact-removed averaged EEG waveforms in no-TMS stop trials (left panel), stop trials with contralateral-TMS at -500 and 0 ms (middle and right panels).
Mentions: The data from the 61-channel scalp EEG (and 1-channel eye-related potential) in all conditions were first segmented in epochs from 1,500 ms before and 1,000 ms after the target time, and all of the segmented data was bunched together for each subject. Next, an independent component (IC) analysis with extended infomax algorithm (Bell and Sejnowski, 1995; Lee et al., 1999) was applied to the EEG data in order to identify and remove the components reflecting TMS-related artifacts and eye-blink- and/or eye-movement-related activities (Jung et al., 2000a,b; Johnson et al., 2012). From the 62 extracted independent components (ICs), the TMS-related ICs were chosen mainly by their time courses; the variance value of the IC during a time period of 20 ms just after the TMS was 20 times larger than those during the rest of the time periods and during no-TMS trials. The results suggested that such ICs impulsively induced huge potentials only when the TMS pulse was delivered. Eye-blink- and eye-movement-related activities were also determined by the time courses, which indicated their inactivation during a task, and scalp topographies of the projection maps, which provided their origin on the edge of anterior sites. Based on these criteria, we could effectively remove TMS-related [11.4 ± 2.7 (mean ± SD for all participants)], eye-blink-related (1 ± 0), and eye-movement-related (0.8 ± 0.4) components and obtain EEG waveforms with little distortion, at least during the time period with two large long-latency TEP components (see Figure A1 in Appendix).

Bottom Line: Transcranial magnetic stimulation (TMS) has often been used in conjunction with electroencephalography (EEG), which is effective for the direct demonstration of cortical reactivity and corticocortical connectivity during cognitive tasks through the spatio-temporal pattern of long-latency TMS-evoked potentials (TEPs).However, it remains unclear what pattern is associated with the inhibition of a planned motor response.TEPs related to motor execution and inhibition were obtained by subtractions between averaged EEG waveforms with and without TMS.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Human Life Sciences, Showa Women's University Tokyo, Japan.

ABSTRACT
Transcranial magnetic stimulation (TMS) has often been used in conjunction with electroencephalography (EEG), which is effective for the direct demonstration of cortical reactivity and corticocortical connectivity during cognitive tasks through the spatio-temporal pattern of long-latency TMS-evoked potentials (TEPs). However, it remains unclear what pattern is associated with the inhibition of a planned motor response. Therefore, we performed TMS-EEG recording during a go/stop task, in which participants were instructed to click a computer mouse with a right index finger when an indicator that was moving with a constant velocity reached a target (go trial) or to avoid the click when the indicator randomly stopped just before it reached the target (stop trial). Single-pulse TMS to the left (contralateral) or right (ipsilateral) motor cortex was applied 500 ms before or just at the target time. TEPs related to motor execution and inhibition were obtained by subtractions between averaged EEG waveforms with and without TMS. As a result, in TEPs induced by both contralateral and ipsilateral TMS, small oscillations were followed by a prominent negative deflection around the TMS site peaking at approximately 100 ms post-TMS (N100), and a less pronounced later positive component (LPC) over the broad areas that was centered at the midline-central site in both go and stop trials. However, compared to the pattern in go and stop trials with TMS at 500 ms before the target time, N100 and LPC were differently modulated in the go and stop trials with TMS just at the target time. The amplitudes of both N100 and LPC decreased in go trials, while the amplitude of LPC decreased and the latency of LPC was delayed in both go and stop trials. These results suggested that TMS-induced neuronal reactions in the motor cortex and subsequent their propagation to surrounding cortical areas might change functionally according to task demand when executing and inhibiting a motor response.

No MeSH data available.


Related in: MedlinePlus