Electrophysiological correlates of proactive and reactive inhibition in a modified visual Go/NoGo task

Impulse control is crucial for everyday functioning in modern society. People with borderline personality disorder (BPD) suffer from impulse control impairment. According to the theory of dual mechanisms of control, motor impulse control can be divided into proactive and reactive modes. Proactive inhibition is involved before the event that might require inhibitory control. Reactive inhibition is initiated after the occurrence of the event that requires inhibitory control. Few studies focused on proactive inhibition in relation to impaired impulse control, moreover electrophysiological evidence is scarce. Therefore, in search for electrophysiological correlates of proactive and reactive inhibitions, we assessed event-related potentials elicited during a modified emotionally neutral visual Go/NoGo task in 28 clinically impulsive BPD patients and 35 healthy control (HC) subjects. In both groups, proactive inhibition was associated with enhanced late prestimulus activity and suppressed poststimulus N2 component. In both groups, reactive inhibition was associated with enhanced poststimulus N2 and P3 components. We found no electrophysiological differences between HC subjects and BPD patients and both groups performed similarly in the task. Hence, the clinically observed impulse control impairment in the BPD might act through different mechanisms other than altered inhibitory control in an emotionally neutral task.

Preparing to React: A Behavioral Study on the Interplay between Proactive and Reactive Action Inhibition

Motor preparation, based on one’s goals and expectations, allows for prompt reactions to stimulations from the environment. Proactive and reactive inhibitory mechanisms modulate this preparation and interact to allow a flexible control of responses. In this study, we investigate these two control mechanisms with an ad hoc cued Go/NoGo Simon paradigm in a within-subjects design, and by measuring subliminal motor activities through electromyographic recordings. Go cues instructed participants to prepare a response and wait for target onset to execute it (Go target) or inhibit it (NoGo target). Proactive inhibition keeps the prepared response in check, hence preventing false alarms. Preparing the cue-coherent effector in advance speeded up responses, even when it turned out to be the incorrect effector and reactive inhibition was needed to perform the action with the contralateral one. These results suggest that informative cues allow for the investigation of the interaction between proactive and reactive action inhibition. Partial errors’ analysis suggests that their appearance in compatible conflict-free trials depends on cue type and prior preparatory motor activity. Motor preparation plays a key role in determining whether proactive inhibition is needed to flexibly control behavior, and it should be considered when investigating proactive/reactive inhibition.

An ERP study on proactive and reactive response inhibition in individuals with schizotypy

Schizotypy, a subclinical group at risk for schizophrenia, has been found to show impairments in response inhibition. However, it remains unclear whether this impairment is accompanied by outright stopping (reactive inhibition) or preparation for stopping (proactive inhibition). We recruited 20 schizotypy and 24 non-schizotypy individuals to perform a modified stop-signal task with electroencephalographic (EEG) data recorded. This task consists of three conditions based on the probability of stop signal: 0% (no stop trials, only go trials), 17% (17% stop trials), and 33% (33% stop trials), the conditions were indicated by the colour of go stimuli. For proactive inhibition (go trials), individuals with schizotypy exhibited significantly lesser increase in go response time (RT) as the stop signal probability increasing compared to non-schizotypy individuals. Individuals with schizotypy also exhibited significantly increased N1 amplitude on all levels of stop signal probability and increased P3 amplitude in the 17% stop condition compared with non-schizotypy individuals. For reactive inhibition (stop trials), individuals with schizotypy exhibited significantly longer stop signal reaction time (SSRT) in both 17% and 33% stop conditions and smaller N2 amplitude on stop trials in the 17% stop condition than non-schizotypy individuals. These findings suggest that individuals with schizotypy were impaired in both proactive and reactive response inhibition at behavioural and neural levels.

Inhibitory Control on a Stop Signal Task in Tourette Syndrome before and after Deep Brain Stimulation of the Internal Segment of the Globus Pallidus

As part of the first randomized double-blind trial of deep brain stimulation (DBS) of the globus pallidus (GPi) in Tourette syndrome, we examined the effect of stimulation on response initiation and inhibition. A total of 14 patients with severe Tourette syndrome were recruited and tested on the stop signal task prior to and after GPi-DBS surgery and compared to eight age-matched healthy controls. Tics were significantly improved following GPi-DBS. The main measure of reactive inhibition, the stop signal reaction time did not change from before to after surgery and did not differ from that of healthy controls either before or after GPi-DBS surgery. This suggests that patients with Tourette syndrome have normal reactive inhibition which is not significantly altered by GPi-DBS.

Mutual synergies between reactive and active inhibitory systems of temperament in the development of children's disruptive behavior: Two longitudinal studies

Individual differences in two inhibitory temperament systems have been implicated as key in the development of early disruptive behaviors. The reactive inhibition system, behavioral inhibition (BI) entails fearfulness, shyness, timidity, and caution. The active inhibition system, or effortful control (EC) entails a capacity to deliberately suppress, modify, or regulate a predominant behavior. Lower scores in each system have been associated with more disruptive behaviors. We examined how the two systems interact, and whether one can alleviate or exacerbate risks due to the other. In two community samples (Study 1, N = 112, ages 2.5 to 4, and Study 2, N = 102, ages 2 to 6.5), we assessed early BI and EC, and future disruptive behaviors (observed disregard for rules in Study 1 and parent-rated externalizing problems in Study 2). Robustly replicated interactions revealed that for children with low BI (relatively fearless), better EC was associated with less disruptive behavior; for children with low EC, more BI was associated with less disruptive behavior. This research extends the investigation of Temperament × Temperament interactions in developmental psychology and psychopathology, and it suggests that reactive and active inhibition systems may play mutually compensatory roles. Those effects emerged after age 2.

A Time Series-Based Point Estimation of Stop Signal Reaction Times: More Evidence on the Role of Reactive Inhibition-Proactive Inhibition Interplay on the SSRT Estimations

The Stop Signal Reaction Time (SSRT) is a latency measurement for the unobservable human brain stopping process, and was formulated by Logan (1994) without consideration of the nature (go/stop) of trials that precede the stop trials. Two asymptotically equivalent and larger indices of mixture SSRT and weighted SSRT were proposed in 2017 to address this issue from time in task longitudinal perspective, but estimation based on the time series perspective has still been missing in the literature. A time series-based state space estimation of SSRT was presented and it was compared with Logan 1994 SSRT over two samples of real Stop Signal Task (SST) data and the simulated SST data. The results showed that time series-based SSRT is significantly larger than Logan’s 1994 SSRT consistent with former Longitudinal-based findings. As a conclusion, SSRT indices considering the after effects of inhibition in their estimation process are larger yielding to hypothesize a larger estimates of SSRT using information on the reactive inhibition, proactive inhibition and their interplay in the SST data.

Mouse Tracking to Explore Motor Inhibition Processes in Go/No-Go and Stop Signal Tasks

Response inhibition relies on both proactive and reactive mechanisms that exert a synergic control on goal-directed actions. It is typically evaluated by the go/no-go (GNG) and the stop signal task (SST) with response recording based on the key-press method. However, the analysis of discrete variables (i.e., present or absent responses) registered by key-press could be insufficient to capture dynamic aspects of inhibitory control. Trying to overcome this limitation, in the present study we used a mouse tracking procedure to characterize movement profiles related to proactive and reactive inhibition. A total of fifty-three participants performed a cued GNG and an SST. The cued GNG mainly involves proactive control whereas the reactive component is mainly engaged in the SST. We evaluated the velocity profile from mouse trajectories both for responses obtained in the Go conditions and for inhibitory failures. Movements were classified as one-shot when no corrections were observed. Multi-peaked velocity profiles were classified as non-one-shot. A higher proportion of one-shot movements was found in the SST compared to the cued GNG when subjects failed to inhibit responses. This result suggests that proactive control may be responsible for unsmooth profiles in inhibition failures, supporting a differentiation between these tasks.

The broken balance in the use of proactive and reactive control in high risk-takers

According to the dual mechanisms of control (DMC), both reactive and proactive control are involved in adjusting behaviors when those are not appropriate to the environment. These control mechanisms have different costs and benefits, orienting the implementation of one or the other control mechanisms as a function of contextual and inter-individual factors. However, to our knowledge, no studies have investigated whether reactive control capacities modulate the use of proactive control. According to the DMC, poor reactive control capacities should be counterbalanced by greater proactive control involvement to efficiently adjust behaviors. We expected that maladaptive behaviors, such as risk-taking, would be characterized by an absence of such compensation. A total of 176 healthy adults performed two reaction time tasks (the Simon and the Stop Signal tasks) and a risk-taking assessment (the Balloon Analog Risk Taking, BART). For each individual, the Stop Signal Reaction Time (SSRT) was used to assess reactive inhibition capacities and the mean duration of the button press in the BART was used as an index of risk-taking propensity. The post-error slowing (PES) in the Simon task reflected the individuals’ tendency to proactively adjust behaviors after an error. Our results showed that smaller SSRT, revealing better reactive inhibition capacities, were associated with shorter PES, suggesting less involvement of proactive adjustments. Moreover, higher the risk-taking propensity, lesser was the proactive control counterbalance for poor reactive inhibition capacities. Risky behaviors, and more broadly maladaptive behaviors, could emerge from the absence of proactive control counterbalance for reactive control deficits