Active Braking of Whole-Arm Reaching Movements Provides Single-Trial Neuromuscular Measures of Movement Cancellation

Abstract

Movement inhibition is an aspect of executive control that can be studied using the countermanding paradigm, wherein subjects try to cancel an impending movement following presentation of a stop signal. This paradigm permits estimation of the stop-signal reaction time or the time needed to respond to the stop signal. Numerous countermanding studies have examined fast, ballistic movements, such as saccades, even though many movements in daily life are not ballistic and can be stopped at any point during their trajectory. A benefit of studying the control of nonballistic movements is that antagonist muscle recruitment, which serves to actively brake a movement, presumably arises in response to the stop signal. Here, nine human participants (2 female) performed a center-out whole-arm reaching task with a countermanding component, while we recorded the activity of upper-limb muscles contributing to movement generation and braking. The data show a clear response on antagonist muscles to a stop signal, even for movements that have barely begun. As predicted, the timing of such antagonist recruitment relative to the stop signal covaried with conventional estimates of the stop-signal reaction time, both within and across subjects. The timing of antagonist muscle recruitment also attested to a rapid reprioritization of movement inhibition, with antagonist latencies decreasing across sequences consisting of repeated stop trials; such reprioritization also scaled with error magnitude. We conclude that antagonist muscle recruitment arises as a manifestation of a stopping process, providing a novel, accessible, and within-trial measure of the stop-signal reaction time. The countermanding or stop-signal paradigm permits estimation of how quickly subjects cancel an impending movement. Traditionally, this paradigm has been studied using simple movements, such as saccadic eye movements or button presses. Here, by measuring upper limb muscle activity while human subjects countermand whole-arm reaching movements, we show that movement cancellation often involves prominent recruitment of antagonist muscles that serves to actively brake the movement, even on movements that have barely begun. The timing of antagonist muscle recruitment correlates with traditional estimates of movement cancellation. Because they can be detected on a single-trial basis, muscle-based measures may provide a new way of characterizing movement cancellation at an unprecedented within-trial resolution.

Differences in unity: the go/no-go and stop signal tasks rely on different inhibitory mechanisms

“…Remarkably, the actual stopping triggered by the stop-stimulus presentation appears to be very fast, at around 140 ms. This is in line with our findings of peripheral EMG decline at around 150 ms in different versions of SST (Atsma et al, 2018;Raud and Huster, 2017), as well as with studies showing the reduction of corticomotor excitability around this time. Nonetheless, it is earlier than expected from the conceptualization of response inhibition as a higher-order cognitive function (e.g.…”

“…These have been observed in a number of conflict tasks and are often considered erroneous response activations that are inhibited before they fully develop into an error (hence the previously used term 'partial error'; Burle et al, 2002;Hasbroucq et al, 1999;Rochet et al, 2014). In the SST, however, these bursts indicate correct response activation in reaction to the go signal that then gets cancelled in response to the stop signal (Atsma et al, 2018;De Jong et al, 1990;Raud and Huster, 2017). Correspondingly, while the onset latency of such EMG reflects response initiation, the starting point for its decline (quantified as the prEMG peak latency) may indicate the time-point of inhibitory effects in the periphery.…”

A single mechanism for global and selective response inhibition under the influence of motor preparation

“…However, most of these occur relatively late in the trial. The prEMG latencies in this study are consistent with recent findings showing that inhibition occurs around 140-180 ms after the stop signal (Raud and Huster, 2017;Atsma et al, 2018;Hannah et al, 2019;Huster et al, 2019;Jana et al, 2020;Raud et al, 2020;Thunberg et al, 2020). Beta power increases in the right inferior frontal gyrus and pre-supplementary motor area within 100 ms following the stop signal (Swann et al, 2009(Swann et al, , 2012.…”

Temporal cascade of frontal, motor and muscle processes underlying human action-stopping

“…Thus, CancelTime narrows the time window for the causal manipulation of neural structures involved in action-stopping. This is in contrast to previous studies that have proposed the onset of intramuscularly-recorded antagonist EMG responses (which is longer than SSRT), can be used as an alternative for estimating the stopping latency (Atsma et al, 2018;Corneil et al, 2013;Goonetilleke et al, 2012Goonetilleke et al, , 2010.…”