An investigation of the dependency of subject-verb agreement on inhibitory control processes in sentence production

Agreement attraction, i.e., the production or acceptance of a verb that agrees with a noun other than the subject of the sentence, can be viewed as a process in which conflicting cues activate competing representations. The aftermath of such competition, in terms of cognitive processes, remains unclear. Using a novel referential communication task for eliciting agreement errors and both group-level manipulation of control demands and a detailed analysis of individual differences, we provide converging evidence for the role of monitoring and inhibitory control processes in agreement attraction for singular-subject sentences. We further demonstrate the dependence of producing plural verbs on such processes, suggesting the singular form is the prepotent default form. Collectively, these findings provide a clear demonstration for the role of monitoring and control processes in agreement computations, and more generally syntactic operations in sentence production.

Dynamic targeting enables domain-general inhibitory control over action and thought by the prefrontal cortex

Over the last two decades, inhibitory control has featured prominently in accounts of how humans and other organisms regulate their behaviour and thought. Previous work on how the brain stops actions and thoughts, however, has emphasised distinct prefrontal regions supporting these functions, suggesting domain-specific mechanisms. Here we show that stopping actions and thoughts recruits common regions in the right dorsolateral and ventrolateral prefrontal cortex to suppress diverse content, via dynamic targeting. Within each region, classifiers trained to distinguish action-stopping from action-execution also identify when people are suppressing their thoughts (and vice versa). Effective connectivity analysis reveals that both prefrontal regions contribute to action and thought stopping by targeting the motor cortex or the hippocampus, depending on the goal, to suppress their task-specific activity. These findings support the existence of a domain-general system that underlies inhibitory control and establish Dynamic Targeting as a mechanism enabling this ability.

How salience enhances inhibitory control: An analysis of electro-cortical mechanisms

Stop-signal tasks (SSTs) combined with human electro-cortical recordings (Event-Related Potentials, ERPs) have revealed mechanisms associated with successful stopping (relative to failed), presumably contributing to inhibitory control. The corresponding ERP signatures have been labeled stop N1 (+/- 100-ms latency), stop N2 (200 ms), and stop P3 (160-250 ms), and argued to reflect more proactive (N1) versus more reactive (N2, P3) mechanisms. However, stop N1 and stop N2, as well as latencies of stop-P3, appear to be quite inconsistent across studies. The present work addressed the possible influence of stop-signal salience, expecting high salience to induce clear stop N1s but reduced stop N2s, and short-latency stop P3s. Three SST varieties were combined with high-resolution EEG. An imperative visual (go) stimulus was occasionally followed by a subsequent (stop) stimulus that signalled to withhold the just initiated response. Stop-Signal Reaction Times (SSRTs) decreased linearly from visual-low to visual-high-salience to auditory. Auditory Stop N1 was replicated. A C1-like visual evoked potential (latency < 100 ms) was observed only with high salience, but not robustly associated with successful versus failed stops. Using the successful-failed contrast a visual stop-N1 analogue (112-156 ms post-stop-signal) was identified, as was right-frontal stop N2, but neither was sensitive to salience. Stop P3 had shorter latency for high than for low salience, and the extent of the early high-salience stop P3 correlated inversely with SSRT. These results suggest that salience-enhanced inhibitory control as manifest in SSRTs is associated with reactive rather than proactive electrocortical mechanisms.

Heterogeneity in PFC-amygdala connectivity in middle childhood, and concurrent interrelations with inhibitory control and anxiety symptomology.

The prefrontal cortex (PFC) is a key brain area in considering adaptive regulatory behaviors. This includes regulatory projections to regions of the limbic system such as the amygdala, where the nature of functional connections may confer lower risk for anxiety disorders. The PFC is also associated with behaviors like executive functioning. Inhibitory control is a behavior encompassed by executive functioning, and is generally viewed favorably for adaptive socioemotional development. Yet, some research suggests that high levels of inhibitory control may actually be a risk factor for some maladaptive developmental outcomes, like anxiety disorders. In a sample of 51 children ranging from 7-9 years old, we examined resting state functional connectivity between regions of the PFC and the amygdala. We used Subgrouping Group Iterative Multiple Model Estimation (S-GIMME) to identify and characterize data-driven subgroups of individuals with similar networks of connectivity between these brain regions. Generated subgroups were collapsed into children characterized by the presence or absence of recovered connections between the PFC and amygdala. We then tested whether inhibitory control, as measured by a stop signal task, moderated the relation between these subgroups and child-reported anxiety symptoms. We found an inverse relation between stop-signal reaction times and reported count of anxiety symptoms when controlling for connectivity group, suggesting that greater inhibitory control was actually related to greater anxiety symptoms, but only when accounting for patterns of PFC-amygdala connectivity. These data suggest that there is a great deal of heterogeneity in the nature of functional connections between the PFC and amygdala during this stage of development. The findings also provide support for the notion of high levels of inhibitory control as a risk factor for anxiety, but trait-level biopsychosocial factors may be important to consider in assessing the nature of risk.

Cardiovascular risk and association with depression in middle-aged and older autistic adults

Cardiovascular risk factors (CVRF) increase during later-life and are associated with depression symptoms and difficulties with executive function among non-autistic older people. Few studies have examined CVRF among autistic people. Using data from the Simons Foundation Powering Autism Research for Knowledge research match, this study examined the frequency of CVRF and associations between CVRF, depression symptoms and executive function in 387 middle-aged and older autistic people (aged 40-83 years). Individuals provided demographic and health information to assess the number of CVRF (presence of hypertension, high cholesterol, diabetes, obesity). Participants also self-reported their depression symptoms and executive functions in the domains of inhibitory control and emotional regulation. CVRF were common among autistic middle-aged and older people, with 28.9% reporting two and 23.2% reporting three or more CVRF. Regression analyses explored the variables associated with depression symptoms. After accounting for the effects of age and sex assigned at birth, CVRF contributed a small but significant amount to the model. A regression model examined the impact of executive function. Emotional regulation (but not inhibitory control), CVRF and age were significantly associated with depression symptoms in middle-aged and older autistic people. In conclusion, CVRF was significantly associated with depression symptoms, and depression symptoms, in turn, were primarily associated with emotional regulation. CVRF occur at high rates in middle-aged and older autistic people but may not be as important a mechanism for depression symptoms as among non-autistic older people.

Anterior cingulate metabolite levels, memory, and inhibitory control in abstinent men and women with Alcohol Use Disorder

Aims: Alcohol use disorder (AUD), has been shown to have harmful cognitive and physiological effects, including altered brain chemistry. Further, although men and women may differ in vulnerability to the neurobiological effects of AUD, results of existing studies have been conflicting. Brain metabolite levels and cognitive functions were examined in a cross section of men with AUD (AUDm) and women with AUD (AUDw) to determine degree of abnormalities after extended periods of abstinence (mean, six years), and to evaluate gender differences in cognitive and metabolite measures. Methods: Participants were 40 abstinent individuals with AUD (22 AUDw, 18 AUDm) and 50 age-equivalent non-AUD comparison participants (26 NCw, 24 NCm). Proton magnetic resonance spectroscopy (MRS) was employed at 3 Tesla to acquire metabolite spectra from the dorsal anterior cingulate cortex (dACC). Brain metabolites N-acetylaspartate (NAA), choline (Cho), myo-Inositol (mI), and glutamate & glutamine (Glx) were examined relative to measures of memory and inhibitory control. Results: Metabolite levels in the AUD group showed no significant differences from the NC group. Memory and inhibitory-control impairments were observed in the AUD group. There also were significant group-specific associations between metabolite ratios and measures of inhibitory control. There were no Group-by-Gender interactions for the four metabolite ratios. Conclusions: These findings demonstrate that brain metabolite levels in men and women with AUD, following long-term abstinence, do not differ from individuals without AUD. The data also provide evidence of associations between metabolite levels and measures of inhibitory control, a functional domain important for curtailing harmful drinking.

Aversive inhibition in adult ADHD and its restoration by mindfulness-based cognitive therapy: A behavioral pilot study

Background: Control over the tendency to make or withhold responses based on contextual Pavlovian information, might play a key role in understanding impulsivity/hyperactivity in ADHD. Here we set out to assess (1) the understudied relation between Pavlovian inhibitory control and hyperactivity/impulsivity in adults with ADHD and (2) whether this inhibition can be enhanced by mindfulness based cognitive therapy (MBCT).Methods: 50 Adult ADHD patients were assessed before and after 8 weeks of treatment as usual (TAU) with (n=24) or without (n=26) MBCT. We employed a sophisticated, well-established Pavlovian-to-instrumental transfer task that quantifies Pavlovian control over instrumental behavior. Results: Task results revealed (1) less aversive Pavlovian inhibition in patients with clinical hyperactivity/impulsivity; and (2) enhanced inhibition after TAU+MBCT compared with TAU. Conclusions: Aversive Pavlovian inhibition plays a role in clinically relevant hyperactivity/impulsivity in adult ADHD and MBCT can be used to enhance this form of inhibition.