Centre of Behavioural and Cognitive Sciences, University of Allahabad (Senate Hall Campus), Prayagraj, Uttar Pradesh, 211002, India.
Exp Brain Res. 2020 Oct;238(10):2417-2432. doi: 10.1007/s00221-020-05901-z. Epub 2020 Aug 9.
A goal-directed flexible behavior warrants our ability to timely inhibit impending movements deemed inappropriate due to an abrupt change in the context. Race model of countermanding rapid saccadic eye movement posits a competition between a preparatory GO process and an inhibitory STOP process rising to reach a fixed threshold. Stop-signal response time (SSRT), which is the average time STOP takes to rise to the threshold, is widely used as a metric to assess the ability to revoke a movement. A reliable estimation of SSRT critically depends on the assumption of independence between GO and STOP process, which has been violated in many studies. In addition, the physiological correlate of stochastic rise of STOP process to a threshold remains unsubstantiated thus far. Here, we introduce a method to estimate the efficacy of inhibitory control on the premise of an alternative model that assumes deceleration of GO process following the stop-signal onset. The average reaction time increased exponentially with the increase in the maximum duration available to attenuate GO process by the stop-signal. Our method estimates saccade procrastination in anticipation of the stop-signal, and the rate of increase in attenuation on GO process. Unlike SSRT, these new metrics are independent of how the stopping performance varies with the delay between go- and stop-signal onsets. We reckon that these metrics together qualify to be considered as an efficient alternative to SSRT for the estimation of individuals' ability to countermand saccades, especially in cases when the assumptions of race model are no longer valid.
目标导向的灵活行为需要我们有能力及时抑制即将发生的运动，因为上下文的突然变化而认为这些运动不合适。反抑制快速眼动的竞赛模型假设预备 GO 过程和抑制性 STOP 过程之间存在竞争，直到达到固定的阈值。停止信号反应时间（SSRT），即 STOP 上升到阈值所需的平均时间，被广泛用作评估撤销运动能力的指标。SSRT 的可靠估计严重依赖于 GO 和 STOP 过程之间独立性的假设，但在许多研究中都违反了这一假设。此外，STOP 过程随机上升到阈值的生理相关性迄今为止尚未得到证实。在这里，我们在假设停止信号出现后 GO 过程减速的替代模型的前提下，引入了一种估计抑制控制效果的方法。平均反应时间随着停止信号的最大持续时间的增加而呈指数增加，以衰减 GO 过程。与 SSRT 不同，这些新指标独立于停止性能随 GO 和停止信号出现之间的延迟变化而变化。我们认为，这些指标共同构成了 SSRT 的有效替代方法，可以用来估计个体抑制眼动的能力，尤其是在竞赛模型的假设不再有效的情况下。
