Reactive Cognitive Control Research Articles

Speed and Accuracy Training Affects Young Children’s Cognitive Control

ABSTRACT Young children tend to rely on reactive cognitive control (e.g. strongly slow down after an error), even when task accuracy would benefit from proactive cognitive control (taking a slower task approach up front). We investigated if giving young primary school children opportunities to repeatedly experience tasks where success rates depend on balancing speed and accuracy by using proactive and reactive cognitive control promotes their selective use of proactive cognitive control strategies. Participants were children from the German-speaking part of Switzerland (N = 105; mean age 7.5 yrs). They were allocated to a “training with feedback,” “training without feedback,” or control condition. They completed a pre- and posttest (Hearts and Flower task), separated by six computerized training tasks over three weeks. We analyzed time-by-condition effects on reaction time, rate-correct, and post-error slowing. In line with our hypotheses, both training groups outperformed the control group on reaction time and rate-correct in the incongruent block. Contrary to expectation, feedback did not enhance the intervention effect and the training group without feedback additionally outperformed control participants on rate-correct in the mixed block and improved their post-error slowing. Thus, our short intervention triggered accelerated development of proactive control in a cognitive conflict task requiring accuracy-speed trade-offs. This shows that during the developmental period in which children are assumed ready for developing proactive cognitive control strategies, repeated experiences over a short time-period can lead to acute improvements. More research is needed to check for long-term benefits and generalizability beyond our sample and the tasks employed.

An Expanded Conceptual Framework for Understanding Irritability in Childhood: The Role of Cognitive Control Processes

Children prone to irritability experience significant functional impairments and internalising and externalising problems. Contemporary models have sought to elucidate the underlying mechanisms in irritability, such as aberrant threat and reward biases to improve interventions. However, the cognitive control processes that underlie threat (e.g., attention towards threats) and reward (e.g., attention towards reward-related cues) biases and the factors which influence the differential activation of positive and negative valence systems and thus leading to maladaptive activation of cognitive control processes (i.e., proactive and reactive control) are unclear. Thus, we aim to integrate extant theoretical and empirical research to elucidate the cognitive control processes underlying threat and reward processing that contribute to irritability in middle childhood and provide a guiding framework for future research and treatment. We propose an expanded conceptual framework of irritability that includes broad intraindividual and environmental vulnerability factors and propose proximal ‘setting’ factors that activate the negative valence and positive valence systems and proactive and reactive cognitive control processes which underpin the expression and progression of irritability. We consider the implications of this expanded conceptualisation of irritability and provide suggestions for future research.

Reduced temporal and spatial stability of neural activity patterns predict cognitive control deficits in children with ADHD.

This study explores the neural underpinnings of cognitive control deficits in ADHD, focusing on overlooked aspects of trial-level variability of neural coding. We employed a novel computational approach to neural decoding on a single-trial basis alongside a cued stop-signal task which allowed us to distinctly probe both proactive and reactive cognitive control. Typically developing (TD) children exhibited stable neural response patterns for efficient proactive and reactive dual control mechanisms. However, neural coding was compromised in children with ADHD. Children with ADHD showed increased temporal variability and diminished spatial stability in neural responses in salience and frontal-parietal network regions, indicating disrupted neural coding during both proactive and reactive control. Moreover, this variability correlated with fluctuating task performance and with more severe symptoms of ADHD. These findings underscore the significance of modeling single-trial variability and representational similarity in understanding distinct components of cognitive control in ADHD, highlighting new perspectives on neurocognitive dysfunction in psychiatric disorders.

A thin line between conflict and reaction time effects on EEG and fMRI brain signals

Abstract The last two decades of electrophysiological and neuroimaging research converged that the activity in the medial frontal cortex plays a pivotal role in cognitive control processes. Notably, the midfrontal theta (MFT) oscillatory EEG power as well as activity in the anterior midcingulate cortex (aMCC) or pre-supplementary motor area (preSMA) were consistently proclaimed as markers of conflict processing. However, these brain signals are strongly correlated with response time (RT) variability in various non-conflict tasks, which overshadows the true nature of their involvement. Our previous study (Beldzik et al., 2022) successfully identified these brain signals during a simultaneous EEG-fMRI experiment implementing Stroop and Simon tasks. Based on the assumption that overcoming the habitual prepotent response during high interference trials requires additional neural resources beyond simple decision variable represented in RTs, here we aim to verify if these markers exhibit a congruency effect beyond RT variations. Furthermore, we explored if these brain signals represent either proactive or reactive cognitive control mechanisms by investigating two widely known behavioral phenomena observed in conflict tasks: proportion congruency and congruency sequence effects. The results revealed partially null findings for MFT activity, yet a distinct cognitive control specialization between aMCC and preSMA. Our study provides novel evidence that the former is involved in proactive control mechanisms, possibly contingency learning, whereas the latter reflects reactive control mechanisms by exhibiting a strong congruency effect regardless of RT variation and responding to adaptive behavior.

Proactive and reactive cognitive control in the absence of learning and memory confounds: Evidence from a cross-modal trial-unique Stroop task.

Goal-directed behaviour is typically conceptualized as striking a balance between two antagonistic cognitive control states such as proactive and reactive control, as demonstrated by conflict phenomena such as the list-wide proportion congruency and congruency sequence effects. However, control-based explanations for these phenomena have come under criticism due to low-level associative regularities that are frequently confounded with conflict manipulations within these experimental designs. In the present study, a novel Stroop paradigm referred to as the "trial-unique Stroop task" was developed to examine whether these effects could be observed in the absence of low-level associative regularities. On each trial, participants typed a word they heard spoken aloud while ignoring a word visually displayed on the screen. Importantly, each word only appeared in a single trial throughout the experiment, and because stimuli and responses were never repeated, there were no low-level associative regularities across trials. Using this paradigm, we observed both congruency sequence (Experiment 1) and list-wide proportion congruency (Experiment 2) effects, providing the strongest evidence to date for control-based explanations of these phenomena. Split-half analyses revealed much higher reliability than traditional colour-word Stroop tasks for the congruency effect (rSB = .98), the congruency sequence effect (rSB = .42), and the list-wide proportion congruency effect (rSB = .85). Moreover, the methodological advantages of the trial-unique Stroop task allow for the independent manipulation of task features related to control, learning, and memory processes. The promising results of this study support the application of the trial-unique Stroop task in this context and open new avenues for future research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Proactive Versus Reactive Control Strategies Differentially Mediate Alcohol Drinking in Male Wistars and P Rats.

Problematic alcohol consumption is associated with deficits in decision-making and alterations in prefrontal cortex neural activity likely contribute. We hypothesized that the differences in cognitive control would be evident between male Wistars and a model of genetic risk: alcohol-preferring P rats. Cognitive control is split into proactive and reactive components. Proactive control maintains goal-directed behavior independent of a stimulus, whereas reactive control elicits goal-directed behavior at the time of a stimulus. We hypothesized that Wistars would show proactive control over alcohol seeking whereas P rats would show reactive control over alcohol seeking. Neural activity was recorded from the prefrontal cortex during an alcohol seeking task with two session types. On congruent sessions, the conditioned stimulus (CS+) was on the same side as alcohol access. Incongruent sessions presented alcohol opposite the CS+. Wistars, but not P rats, made more incorrect approaches during incongruent sessions, suggesting that Wistars utilized the previously learned rule. This motivated the hypothesis that neural activity reflecting proactive control would be observable in Wistars but not P rats. While P rats showed differences in neural activity at times of alcohol access, Wistars showed differences prior to approaching the sipper. These results support our hypothesis that Wistars are more likely to engage in proactive cognitive control strategies whereas P rats are more likely to engage in reactive cognitive control strategies. Although P rats were bred to prefer alcohol, the differences in cognitive control may reflect a sequela of behaviors that mirror those in humans at risk for an AUD.

Event-Related Potentials in Cued Go/NoGo Task are Possible Neuromarkers of Monotony

Monotony or mental fatigue occurs during performing low-content and monotonous work, including the work of the operator. It is accompanied by a decrease in the concentration of attention and the speed of its switching, as well as slowing in the processes of perception and motor reactions, which can lead to a loss of vigilance, self-control and the occurrence of drowsiness and, consequently, an increase in the risk of industrial injuries and accidents. In this regard, an urgent task is to develop methods for monitoring the human condition in the process of performing monotonous activities. We investigated the effect of monotony on event-related potentials (ERPs) in the visual cued Go/NoGo test. We analyzed 31-channel EEG data of 25 healthy subjects recorded before and after performing four tests with a total duration of around 1.5 hours, representing the same type of tasks with different instructions and simulating the conditions of monotonous work. After performing four tests, we observe an increase of P2 wave, decrease of the P3 Cue wave and the contingent negative variation (CNV) wave in the Cue condition, as well as the decrease of P300 wave in the NoGo condition. The results obtained in this work are assumed to reflect attenuation in proactive and reactive cognitive control during monotony and allow us to consider the P2, P3 Cue, CNV and P3 NoGo waves as possible candidates for the role of neuromarkers of monotony, which makes it promising to use these indicators in systems for monitoring the human condition during operating work.

On the relationship between emotions and cognitive control: Evidence from an observational study on emotional priming Stroop task.

Evidence is discordant regarding how emotional processing and cognitive control interact to shape behavior. This observational study sought to examine this interaction by looking at the distinction between proactive and reactive modes of control and how they relate to emotional processing. Seventy-four healthy participants performed an emotional priming Stroop task. On each trial, target stimuli of a spatial Stroop task were preceded by sad or neutral facial expressions, providing two emotional conditions. To manipulate the requirement of both proactive and reactive control, the proportion of congruent trials (PC) was varied at the list-wide (LWPC) and item-specific (ISPC) levels, respectively. We found that sad priming led to behavioral costs only in trials with low proactive and reactive cognitive control demands. Our findings suggest that emotional processing affects cognitive processes other than cognitive control in the Stroop task. Moreover, both proactive and reactive control modes seem effective in overcoming emotional interference of priming stimuli.

Cognitive control impairment in ax-continuous performance test in patients with schizophrenia: A pilot EEG study.

This study aimed to investigate the mechanism of cognitive control impairment in patients with schizophrenia (SPs) using electroencephalogram (EEG). A total of 17 SPs and 17 healthy controls (HCs) were included in this study. We measured the EEG activity, whereas they performed the AX-continuous performance test which consisted of the preparatory phase and the response phase. The MATRICS Consensus Cognitive Battery (MCCB) was used for cognitive function, and the Positive and Negative Syndrome Scale (PANSS) was used for clinical symptom assessment. A univariate linear regression model was used to explore the relationships among behavioral index, event-related potentials (ERPs), rhythmic oscillation power, and score of MCCB and PANSS. A significant difference was found in response accuracy and reaction time (RT) during the preparatory phase between patients and HCs (p<.05). During the response phase, the SPs exhibited longer RT than the HCs (p<.05). Analysis of the ERPs revealed that the amplitude of P3a on BX clues was significantly smaller in SPs than in HCs (p<.05). Additionally, the midline frontal theta power of neural oscillation was significantly lower in the SPs than in NCs both during the preparatory and response phases. The accuracies on BX clues (r=.694, p=.002) and d'context (r=.698, p=.002) were positively correlated with MCCB scores. The present study revealed that patients with schizophrenia have deficits both in proactive and reactive cognitive control, with a greater reliance on reactive control during conflict resolution. The neural mechanisms of the cognitive control impairment may involve the inability to engage additional neural resources for proactive control, and a reduction in frontal midline theta power during both proactive and reactive control. The severity of proactive control impairment is positively correlated with an increased tendency to rely on reactive control.

Neural correlates of cognitive control deficits in pediatric mild traumatic brain injury.

There is a growing body of research showing that cerebral pathophysiological processes triggered by pediatric mild traumatic brain injury (pmTBI) may extend beyond the usual clinical recovery timeline. It is paramount to further unravel these processes, because the possible long-term cognitive effects resulting from ongoing secondary injury in the developing brain are not known. In the current fMRI study, neural processes related to cognitive control were studied in 181 patients with pmTBI at sub-acute (SA; ~1 week) and early chronic (EC; ~4 months) stages post-injury. Additionally, a group of 162 age- and sex-matched healthy controls (HC) were recruited at equivalent time points. Proactive (post-cue) and reactive (post-probe) cognitive control were examined using a multimodal attention fMRI paradigm for either congruent or incongruent stimuli. To study brain network function, the triple-network model was used, consisting of the executive and salience networks (collectively known as the cognitive control network), and the default mode network. Additionally, whole-brain voxel-wise analyses were performed. Decreased deactivation was found within the default mode network at the EC stage following pmTBI during both proactive and reactive control. Voxel-wise analyses revealed sub-acute hypoactivation of a frontal area of the cognitive control network (left pre-supplementary motor area) during proactive control, with a reversed effect at the EC stage after pmTBI. Similar effects were observed in areas outside of the triple-network during reactive control. Group differences in activation during proactive control were limited to the visual domain, whereas for reactive control findings were more pronounced during the attendance of auditory stimuli. No significant correlations were present between task-related activations and (persistent) post-concussive symptoms. In aggregate, current results show alterations in neural functioning during cognitive control in pmTBI up to 4 months post-injury, regardless of clinical recovery. We propose that subacute decreases in activity reflect a general state of hypo-excitability due to the injury, while early chronic hyperactivation represents a compensatory mechanism to prevent default mode interference and to retain cognitive control.

Reward expectation enhances reactive control of distraction by emotionally negative stimuli.

Reward expectation reduces the interference of task-irrelevant emotional distractors by improving cognitive control. The current study investigated the effects of reward expectation on proactive and reactive cognitive control of negative distractors. Reward expectation (incentive vs. nonincentive trials) was manipulated by a precue signaling the opportunity to gain an extra monetary reward for fast and accurate response on a given trial, followed by the trial display with the response-relevant target stimuli in the periphery and an irrelevant, negative, or neutral distractor in the center. The frequency of negative distractors (high vs. low) was manipulated to induce a proactive or reactive control mode (between-participants factor). Mutilation images and angry faces were used as negative distractors in Experiments 1 (1A and 1B) and 2, respectively. Results revealed performance to be generally facilitated by reward expectation, and impaired by negative (vs. neutral) distractors. Importantly, reward expectation rendered a reduction of negative-distractor interference when observers operated in reactive (vs. proactive) control mode. Moreover, the interaction between reward expectation and cognitive control strategy was modulated by the emotional strength of the negative distractors (mutilation images vs. angry faces). Thus, reward incentive leads to more effective filtering of negative (emotional) distractors when these occur rarely (reactive control) rather than frequently (proactive control), especially with emotionally strong negative distractors. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Differentiation between fetal and postnatal iron deficiency in altering brain substrates of cognitive control in pre-adolescence

BackgroundEarly iron deficiency (ID) is a common risk factor for poorer neurodevelopment, limiting children’s potential and contributing to global burden. However, it is unclear how early ID alters the substrate of brain functions supporting high-order cognitive abilities and whether the timing of early ID matters in terms of long-term brain development. This study aimed to examine the effects of ID during fetal or early postnatal periods on brain activities supporting proactive and reactive cognitive control in pre-adolescent children.MethodsParticipants were part of a longitudinal cohort enrolled at birth in southeastern China between December 2008 and November 2011. Between July 2019 and October 2021, 115 children aged 8–11 years were invited to participate in this neuroimaging study. Final analyses included 71 children: 20 with fetal ID, 24 with ID at 9 months (postnatal ID), and 27 iron-sufficient at birth and 9 months. Participants performed a computer-based behavioral task in a Magnetic Resonance Imaging scanner to measure proactive and reactive cognitive control. Outcome measures included accuracy, reaction times, and brain activity. Linear mixed modeling and the 3dlme command in Analysis of Functional NeuroImages (AFNI) were separately used to analyze behavioral performance and neuroimaging data.ResultsFaster responses in proactive vs. reactive conditions indicated that all groups could use proactive or reactive cognitive control according to contextual demands. However, the fetal ID group was lower in general accuracy than the other 2 groups. Per the demands of cues and targets, the iron-sufficient group showed greater activation of wide brain regions in proactive vs. reactive conditions. In contrast, such condition differences were reversed in the postnatal ID group. Condition differences in brain activation, shown in postnatal ID and iron-sufficient groups, were not found in the fetal ID group. This group specifically showed greater activation of brain regions in the reward pathway in proactive vs. reactive conditions.ConclusionsEarly ID was associated with altered brain functions supporting proactive and reactive cognitive control in childhood. Alterations differed between fetal and postnatal ID groups. The findings imply that iron supplement alone is insufficient to prevent persisting brain alterations associated with early ID. Intervention strategies in addition to the iron supplement should consider ID timing.

Prospective memory decision control: A computational model of context effects on prospective memory.

Prospective memory (PM) tasks require remembering to perform a deferred action and can be associated with predictable contexts. We present a theory and computational model, prospective memory decision control (PMDC), of the cognitive processes by which context supports PM. Under control conditions, participants completed lexical decisions. Under PM conditions, participants had the additional PM task of responding to letter strings containing certain syllables. Stimuli were presented in one of two colors, with color potentially changing after each set of four trials. A pretrial colored fixation was presented before each set. Under control and PM standard conditions, fixation color was meaningless. Under PM context conditions, fixation color indicated whether a PM target could occur within the next set. We replicated prior findings of higher PM accuracy for context compared to standard conditions, and the expected variation in PM costs (slowed lexical decisions) as a function of context relevance. PMDC, which formalizes PM as a process of evidence accumulation among ongoing and PM task responses, accounted for the impact of context on PM costs and accuracy via proactive and reactive cognitive control. Increased ongoing task thresholds and decreased PM thresholds in relevant contexts indicated proactive control. With context provision, PM accumulation rates on PM trials increased, as did inhibition of accumulation to competing responses, indicating reactive control. Although an observed capacity-sharing effect explained some portion of PM costs, we found no evidence that participants redirected more capacity from the ongoing to the PM task when contextually cued to relevant contexts. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Shared Neural Activity But Distinct Neural Dynamics for Cognitive Control in Monkey Prefrontal and Parietal Cortex.

To better understand how prefrontal networks mediate forms of cognitive control disrupted in schizophrenia, we translated a variant of the AX continuous performance task that measures specific deficits in the human disease to 2 male monkeys and recorded neurons in PFC and parietal cortex during task performance. In the task, contextual information instructed by cue stimuli determines the response required to a subsequent probe stimulus. We found parietal neurons encoding the behavioral context instructed by cues that exhibited nearly identical activity to their prefrontal counterparts (Blackman et al., 2016). This neural population switched their preference for stimuli over the course of the trial depending on whether the stimuli signaled the need to engage cognitive control to override a prepotent response. Cues evoked visual responses that appeared in parietal neurons first, whereas population activity encoding contextual information instructed by cues was stronger and more persistent in PFC. Increasing cognitive control demand biased the representation of contextual information toward the PFC and augmented the temporal correlation of task-defined information encoded by neurons in the two areas. Oscillatory dynamics in local field potentials differed between cortical areas and carried as much information about task conditions as spike rates. We found that, at the single-neuron level, patterns of activity evoked by the task were nearly identical between the two cortical areas. Nonetheless, distinct population dynamics in PFC and parietal cortex were evident. suggesting differential contributions to cognitive control.SIGNIFICANCE STATEMENT We recorded neural activity in PFC and parietal cortex of monkeys performing a task that measures cognitive control deficits in schizophrenia. This allowed us to characterize computations performed by neurons in the two areas to support forms of cognitive control disrupted in the disease. Subpopulations of neurons in the two areas exhibited parallel modulations in firing rate; and as a result, all patterns of task-evoked activity were distributed between PFC and parietal cortex. This included the presence in both cortical areas of neurons reflecting proactive and reactive cognitive control dissociated from stimuli or responses in the task. However, differences in the timing, strength, synchrony, and correlation of information encoded by neural activity were evident, indicating differential contributions to cognitive control.

Poorer sleep health is associated with altered brain activation during cognitive control processing in healthy adults.

This study investigated how proactive and reactive cognitive control processing in the brain was associated with habitual sleep health. BOLD fMRI data were acquired from 81 healthy adults with normal sleep (41 females, age 20.96-39.58years) during a test of cognitive control (Not-X-CPT). Sleep health was assessed in the week before MRI scanning, using both objective (actigraphy) and self-report measures. Multiple measures indicating poorer sleep health-including later/more variable sleep timing, later chronotype preference, more insomnia symptoms, and lower sleep efficiency-were associated with stronger and more widespread BOLD activations in fronto-parietal and subcortical brain regions during cognitive control processing (adjusted for age, sex, education, and fMRI task performance). Most associations were found for reactive cognitive control activation, indicating that poorer sleep health is linked to a "hyper-reactive" brain state. Analysis of time-on-task effects showed that, with longer time on task, poorer sleep health was predominantly associated with increased proactive cognitive control activation, indicating recruitment of additional neural resources over time. Finally, shorter objective sleep duration was associated with lower BOLD activation with time on task and poorer task performance. In conclusion, even in "normal sleepers," relatively poorer sleep health is associated with altered cognitive control processing, possibly reflecting compensatory mechanisms and/or inefficient neural processing.

Proactive and Reactive Inhibitory Control Strategies: Exploring the Impact of Interindividual Variables on an ERP Continuous Performance Task (AX-CPT).

According to the Dual Mechanisms of Control (DMC) framework, cognitive control can be divided into two strategies: proactive cognitive control, which relies mainly on the active maintenance of contextual information relevant to the ongoing task; and reactive cognitive control, which is a form of transient control triggered by an external cue. Although cognitive control has been studied extensively, little is known about the specificities of inhibition within the framework of the DMC model and the influence of interindividual variables on inhibitory control.Thanks to an inhibitory version of the continuous performance task (CPT), we studied behavioral performances and Event-Related Potentials (ERPs) related to proactive and reactive inhibition, and their links to psychological profile and cognitive performances. One hundred and five young adults underwent the task, along with a short clinical and cognitive evaluation.We were able to observe ERPs related to proactive (cue-N1, cue-N2, cue-P3, and the contingent negative variation) and reactive inhibitory control (target-N2 and target-P3). Our results showed that proactive strategies appeared to be linked with impulsivity, working memory abilities, dominant response inhibition, gender, and the consumption pattern of nicotine. Reactive strategies appeared to be linked with attentional and working memories abilities.Overall, the inhibitory AX-CPT allowed a specific investigation of cognitive control within the framework of the DMC based on behavioral and ERP variables. This provided us an opportunity to investigate the principal ERP components related to proactive and reactive inhibitory control strategies as well as to link them with specific clinical and cognitive variables.

Give and take between proactive and reactive cognitive control during attentional suppression

Give and take between proactive and reactive cognitive control during attentional suppression

Proactive and reactive cognitive control for emotional conflict in individuals with high schizotypy: An ERP study

ObjectiveThe present study aimed to examine how individuals with high schizotypy, a high risk group of schizophrenia patients, resolve emotional conflict in proactive and reactive control and the underlying neural mechanisms. MethodsThirty-two individuals with high schizotypy and 30 matched individuals with low schizotypy completed an emotional face–word Stroop task with electroencephalographic data recorded. The proportion of incongruent trials was manipulated in the task to induce proactive control (mostly incongruent trials context, MI context) or reactive control (mostly congruent trials context, MC context). Two event-related potential (ERP) components (N170 and N2) were examined, which represent face processing and cognitive control processes, respectively. ResultsIn the MC context, significantly decreased N2 and N170 amplitudes were found in high schizotypy individuals compared with low schizotypy individuals, suggesting abnormal neural activity of reactive control in high schizotypy individuals. No significant differences were found between the two groups in the MI context. ConclusionsThese results provide initial evidence for dissociation of neural activity of proactive and reactive control on emotional conflict in individuals with high schizotypy. SignificanceThe current findings provide important insight into the emotional conflict resolution in the schizophrenia spectrum.

Age Differences in the Tradeoff between Proactive and Reactive Cognitive Control in Emotional Information Processing.

Greater well-being in older adults stems from more effective emotion regulation strategies, highlighting the role of cognitive control. However, cognitive control involves different subsystems, and it is still unclear whether different subsystems have different effects on different emotional information processing. The Dual Mechanisms of Control (DMC) theory postulates that cognitive control can operate in two distinct modes, namely proactive control (a “proactive” preparatory mode) and reactive control (a “reactive” wait-and-see mode). This study created an emotional AX-CPT task to explore differences in cognitive control tradeoff between youth and older adults when processing emotional information. The results found that youth had significantly higher error rates on the emotional-neutral sequence than older adults regardless of the valence of emotional information; only in the negative condition did older adults have higher error rates on both the sad-sad and neutral-sad sequences than youth; this phenomenon was not found in the positive condition. The study showed that, in emotional information processing, youth preferred proactive control over older adults; in negative information processing, older adults preferred reactive control strategies over youth; in positive information processing, older adults showed a similar cognitive control pattern to youth, and proactive control was enhanced.

The Effects of Neural Gain on Reactive Cognitive Control

Fluctuations in global neural gain, arising from brainstem arousal systems, have been found to shape attention, learning, and decision-making as well as cortical state. Comparatively, little is known about how fluctuations in neural gain affect cognitive control. In the present study, we examined this question using a combination of behavioral methods, pupillometry, and computational modeling. Simulations of a comprehensive model of the Stroop task incorporating task conflict and both proactive and reactive forms of control indicated that increasing global gain led to an overall speeding of reaction times, increased Stroop interference, and decreased Stroop facilitation. Pupil analyses revealed that the pre-trial pupil derivative (i.e., rate of change), a putative non-invasive index of global gain, showed the same diagnostic relationships with the Stroop-task performance of human participants. An analysis of the internal model dynamics suggested that a gain-related increase in task conflict and corresponding (within-trial) increase in reactive control are vital for understanding this pattern of behavioral results. Indeed, a similar connectionist model without this task-conflict-control loop could not account for the results. Our study suggests that spontaneous fluctuations in neural gain can have a significant impact on reactive cognitive control.