Measurement of the response inhibition network in a brief battery of tasks: Introducing an assessment of reactive and proactive inhibition processes.

Traditional response inhibition tasks are assumed to capture one’s ability to inhibit a response. This ability, however, requires a reactive process and a proactive process, post-error slowing (PES). Recent evidence shows that Stop-Signal Tasks (SSTs) measure the reactive process, and while the Sustained Attention to Response Task measures overall response inhibition, that measure is confounded by a proactive process. Since the diseases associated with response inhibition deficits often co-occur with symptoms that diminish the capacity for lengthy behavioural testing, and, since it is unknown to which process such decrements can be attributed and where in the brain these processes are generated, rapid and precise measurement of reactive and proactive processes is important. To address these issues, we administered a battery of four response inhibition tasks to healthy young adults (N = 123), two SSTs and two Go/No-Go tasks. In three tasks, we implemented adaptations to allow direct observation of proactive inhibition, reactive inhibition, and overall response inhibition. We introduce a novel cueing procedure to investigate the possibility of a predictive mechanism of proactive inhibition, arguing that slower response times on trials with a higher Stop/No-Go probability indicate predictive proactive inhibition. Based on these findings, we propose a novel demarcation to proactive inhibition: remedial proactive inhibition (PES), and predictive proactive inhibition. Additionally, we provide empirical support for a Bayesian adaptive staircase (Livesey & Livesey, 2016) that allows rapid convergence on estimates of reactive inhibition in SSTs in as few as 20 trials that are robust against potential predictive proactive inhibition confounds.