An Activation Threshold Model for Response Inhibition

Abstract

Reactive response inhibition (RI) is the cancellation of a prepared response when it is no longer appropriate. Selectivity of RI can be examined by cueing the cancellation of one component of a prepared multi-component response. This substantially delays execution of other components. There is debate regarding whether this response delay is due to a selective neural mechanism. Here we propose a computational activation threshold model (ATM) and test it against a classical “horse-race” model using behavioural and neurophysiological data from partial RI experiments. The models comprise both facilitatory and inhibitory processes that compete upstream of motor output regions. Summary statistics (means and standard deviations) of predicted muscular and neurophysiological data were fit in both models to equivalent experimental measures by minimizing a Pearson Chi-square statistic. The ATM best captured behavioural and neurophysiological dynamics of partial RI. The ATM demonstrated that the observed modulation of corticomotor excitability during partial RI can be explained by nonselective inhibition of the prepared response. The inhibition raised the activation threshold to a level that could not be reached by the original response. This was necessarily followed by an additional phase of facilitation representing a secondary activation process in order to reach the new inhibition threshold and initiate the executed component of the response. The ATM offers a mechanistic description of the neural events underlying RI, in which partial movement cancellation results from a nonselective inhibitory event followed by subsequent initiation of a new response. The ATM provides a framework for considering and exploring the neuroanatomical constraints that underlie RI.

Age-related alterations in the modulation of intracortical inhibition during stopping of actions

“…They stimulated right M1 during a bimanual stop-signal anticipation task in which either part of the response or the whole response should be cancelled without foreknowledge. The increase in LICI during the foreperiod when stop trials were introduced was explained as a ‘tonic inhibitory process’ which raises the threshold for responding [24,38,45]. Due to the higher threshold, a further increase in facilitation is needed to reinitiate a subcomponent of the suppressed movement, causing delays in the ensuing component [23,24].…”

The Reaction Switching Produces A Greater Bias to Prepotent Response than Reaction Inhibition

“…Second, the response switching is as effective as the response inhibition. Switching reaction required inhibition of the prepotent response followed the activated of a new reaction [1,8,24,29]. When a rare stimulus is presented and reaction should not be changed [17][18][19][20], the accuracy of execution is close to 100%.…”

“…These results were confirmed in the studies [22,23] during the selective inhibition of motor response using myography and transcranial magnetic stimulation. Based on these data, the Activation Threshold Model (ATM) [24] was developed. Unlike previous models, ATM assumes that there is a change in the response excitation and inhibition thresholds in different phases of motor response.…”

Non-selective response inhibition in equiprobable Go/NoGo task: Bayesian analysis of fMRI data

“…However, over time, it has become apparent that under several conditions, non-selectivity of response inhibition can in principle occur. Studies on nonselectivity of response inhibition typically focus on the possible brain mechanisms for nonselective inhibition of motor responses in the settings of interference among multiple concurrent response options associated exclusively with NoGo stimuli (De Jong, Coles & Logan, 1995, Coxon, Stinear & Byblow, 2007, Aron & Verbruggen, 2008, Frank, 2006, Duque & Ivry, 2009, Duque et al, 2010, MacDonald et al, 2017. Moreover, the possibility of involvement of nonselective response inhibition not only for NoGo stimuli but also for Go stimuli was previously supposed by Criaud et al (2017).…”

“…Manipulating the probability of the occurrence of "inhibitory" stimuli and the subjects' awareness of the probability of the appearance may slow down the motor response (Chevrier, Noseworthy & Schachar, 2007, Jaffard et al, 2007, Boulinguez et al, 2008, Vink et al, 2014, Vink et al, 2015, Dunovan et al, 2015, Meffert et al, 2016, Hsieh, Wu & Tang, 2016. Moreover, when it is necessary to suppress a specific action selectively, that action is inhibited as well as all other potential actions (Coxon, Stinear & Byblow, 2007, Aron & Verbruggen, 2008, Duque & Ivry, 2009, Duque et al, 2010, MacDonald et al, 2017. In attempting to explain the effects mentioned above, several authors proposed the concept of non-selective ("global") response inhibition (Frank, 2006, Aron, 2011, Criaud et al, 2017.…”