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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.


Task designs of experiments. (A) Illustrations of the display for the go/stop task. The trial type is noted on the right side, and the time scale is displayed at the bottom. (B) Illustrations of trial structure for the go/stop task with and without transcranial magnetic stimulation (TMS). The time scale is displayed at the bottom. The vertical lines at -1,000 ms represent the indicator onset, the vertical dashed lines at 0 ms represent the target, and the vertical dotted lines represent the feedback onset. The small triangles represent the time points at which TMS was delivered (TMS time). The trial type is noted on the right side, with the TMS time, stop time (ST), and total number of trials. In the stop trials, the time points at which an indicator stopped are shown with vertical thin bars.
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Figure 1: Task designs of experiments. (A) Illustrations of the display for the go/stop task. The trial type is noted on the right side, and the time scale is displayed at the bottom. (B) Illustrations of trial structure for the go/stop task with and without transcranial magnetic stimulation (TMS). The time scale is displayed at the bottom. The vertical lines at -1,000 ms represent the indicator onset, the vertical dashed lines at 0 ms represent the target, and the vertical dotted lines represent the feedback onset. The small triangles represent the time points at which TMS was delivered (TMS time). The trial type is noted on the right side, with the TMS time, stop time (ST), and total number of trials. In the stop trials, the time points at which an indicator stopped are shown with vertical thin bars.

Mentions: All participants conducted a timing-coincident go/stop task (Figure 1A). In the task, each trial began with presentation of a white bar against a gray background with two small black triangles indicating a target at the center of the display. After 600 ms, a green indicator moved upward from the bottom of the bar at a constant rate, reaching the target (black triangles) in 1,000 ms and the top of the bar in 1,400 ms. The time point at which the indicator began moving upward was referred to as the indicator onset. Participants were instructed to click the mouse in order to stop the moving green indicator at the target (referred to as go trials). In half of the trials, the moving green indicator unexpectedly stopped and turned red just before it reached the target. The participant was instructed to withhold their click when the moving green indicator stopped and turned red (referred to as stop trials). The time point at which the indicator stopped (stop time: ST) was set at -250, -200, -150, and -100 ms relative to the target. In each go and stop trial, after 1,400 ms of the indicator onset, visual feedback about a participant’s performance [response time (RT) relative to target (ms) or “miss” for go trials; “stop!!” or “false alarm” with RT (ms) for stop trials] was presented for 500 ms on the central bar. This constant time setting was used to prevent participants’ eye blinks before the visual feedback onset. The participant was informed that the indicator in some trials would be easy to stop, and that it would be more difficult or impossible to stop in other trials because it would be too close to the target.


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

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

Task designs of experiments. (A) Illustrations of the display for the go/stop task. The trial type is noted on the right side, and the time scale is displayed at the bottom. (B) Illustrations of trial structure for the go/stop task with and without transcranial magnetic stimulation (TMS). The time scale is displayed at the bottom. The vertical lines at -1,000 ms represent the indicator onset, the vertical dashed lines at 0 ms represent the target, and the vertical dotted lines represent the feedback onset. The small triangles represent the time points at which TMS was delivered (TMS time). The trial type is noted on the right side, with the TMS time, stop time (ST), and total number of trials. In the stop trials, the time points at which an indicator stopped are shown with vertical thin bars.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Task designs of experiments. (A) Illustrations of the display for the go/stop task. The trial type is noted on the right side, and the time scale is displayed at the bottom. (B) Illustrations of trial structure for the go/stop task with and without transcranial magnetic stimulation (TMS). The time scale is displayed at the bottom. The vertical lines at -1,000 ms represent the indicator onset, the vertical dashed lines at 0 ms represent the target, and the vertical dotted lines represent the feedback onset. The small triangles represent the time points at which TMS was delivered (TMS time). The trial type is noted on the right side, with the TMS time, stop time (ST), and total number of trials. In the stop trials, the time points at which an indicator stopped are shown with vertical thin bars.
Mentions: All participants conducted a timing-coincident go/stop task (Figure 1A). In the task, each trial began with presentation of a white bar against a gray background with two small black triangles indicating a target at the center of the display. After 600 ms, a green indicator moved upward from the bottom of the bar at a constant rate, reaching the target (black triangles) in 1,000 ms and the top of the bar in 1,400 ms. The time point at which the indicator began moving upward was referred to as the indicator onset. Participants were instructed to click the mouse in order to stop the moving green indicator at the target (referred to as go trials). In half of the trials, the moving green indicator unexpectedly stopped and turned red just before it reached the target. The participant was instructed to withhold their click when the moving green indicator stopped and turned red (referred to as stop trials). The time point at which the indicator stopped (stop time: ST) was set at -250, -200, -150, and -100 ms relative to the target. In each go and stop trial, after 1,400 ms of the indicator onset, visual feedback about a participant’s performance [response time (RT) relative to target (ms) or “miss” for go trials; “stop!!” or “false alarm” with RT (ms) for stop trials] was presented for 500 ms on the central bar. This constant time setting was used to prevent participants’ eye blinks before the visual feedback onset. The participant was informed that the indicator in some trials would be easy to stop, and that it would be more difficult or impossible to stop in other trials because it would be too close to the target.

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.