Inhibitory Processes Research Articles

Transfer of congruency effects between Stroop and multiplication tasks: Evidence that retrieval of multiplication facts requires inhibitory control.

Inhibitory control is classically considered a domain-general process, yet recent findings suggest it may operate in context-specific ways. This has important implications for theories in other cognitive domains, such as mathematics, in which inhibitory control is proposed to play a key role. Inhibitory control has been implicated in resolving interference between competing number facts when retrieving them from memory, yet clear evidence for this is lacking. Here we report two pre-registered experiments with adults that investigated transfer of inhibitory control between interleaved Stroop and multiplication fact retrieval trials. Experiment 1 (n=450) measured the congruency sequence effect, where transfer of inhibitory control between trials leads to a reduced congruency effect following an incongruent trial. Experiment 2 (n=370) measured transfer of the list-wide proportion congruency effect, where the congruency effect is reduced when incongruent trials are more frequent. We found evidence of transfer of the congruency sequence effect between Stroop and multiplication. This did not differ depending on whether the Stroop task used number or animal stimuli. There was no transfer of the list-wide proportion congruency effect. These results suggest that reactive, transient domain-general inhibitory control processes are involved in retrieving multiplication facts from memory. Our findings have implications for theories of cognitive control and mathematical cognition, but caution should be taken in interpreting implications for educational interventions.

Plasticity of human resilience mechanisms.

The hippocampus's vulnerability to trauma-induced stress can lead to pathophysiological disturbances that precipitate the development of posttraumatic stress disorder (PTSD). The mechanisms of resilience that foster remission and mitigate the adverse effects of stress remain unknown. We analyzed the evolution of hippocampal morphology between 2016/2017 and 2018/2019, as well as the memory control mechanisms crucial for trauma resilience. Participants were individuals exposed to the 2015 Paris terrorist attacks (N = 100), including chronic (N = 34) and remitted (N = 19) PTSD, and nonexposed (N = 72). We found that normalization of inhibitory control processes, which regulate the resurgence of intrusive memories in the hippocampus, not only predicted PTSD remission but also preceded a reduction in traumatic memories. Improvement in control mechanisms was associated with the interruption of stress-induced atrophy in a hippocampal region that includes the dentate gyrus. Human resilience to trauma is characterized by the plasticity of memory control circuits, which interacts with hippocampal neuroplasticity.

Sex differences in aggression and its neural substrate in a cichlid fish

Aggression is ubiquitous among social species and can function to maintain social dominance hierarchies. The African cichlid fish Astatotilapia burtoni is an ideal study species for studying aggression due to their dominance hierarchy and robust behavioral repertoire. To further understand the potential sex differences in aggression in this species, we characterized aggression in male and female A. burtoni in a mirror assay. We then quantified neural activation patterns in brain regions of the social behavior network (SBN) to investigate if differences in behavior are reflected in the brain with immunohistochemistry by detecting the phosphorylated ribosome marker phospho-S6 ribosomal protein (pS6), a marker for neural activation. We found that A. burtoni perform both identical and sex-specific aggressive behaviors in response to a mirror assay. Females had greater pS6 immunoreactivity than males in the Vv (ventral part of the ventral telencephalon), a homolog of the lateral septum in mammals. Males but not females had higher pS6 immunoreactivity in the ATn after the aggression assay. The ATn (anterior tuberal nucleus) is a homolog of the ventromedial hypothalamus in mammals, which is strongly implicated in the regulation of aggression in males. Several regions also have higher pS6 immunoreactivity in negative controls than fish exposed to a mirror, implicating a role for inhibitory neural processes in suppressing aggression until a relevant stimulus is present. Male and female A. burtoni display both similar and different behavioral patterns in aggression in response to a mirror assay. There are also sex differences in the corresponding neural activation patterns in the SBN. In mirror males but not females, the ATn clusters with the POA, revealing a functional connectivity of these regions that is triggered in an aggressive context in males. These findings suggest that distinct neural circuitry underlie aggressive behavior in male and female A. burtoni, serving as a foundation for future work investigating the molecular and neural underpinnings of sex differences in behavior in this species to reveal fundamental insights into understanding aggression.

Social support, spirituality, and executive functions: An event-related potential (ERP) study of neural mechanisms of cultural protective factors in American Indians (AIs).

A resilience-based approach in American Indian (AI) communities focuses on inherent sociocultural assets that may act as protective resilience buffers linked to mitigated mental health risks (e.g., deep-rooted spiritual, robust social support networks). Executive control functions are implicated as mechanisms for protective factors, but little evidence exists on the underlying neurocognitive mechanisms that support resilience. This study examined how sustainable and community-centric factors of social support and Native Spirituality were linked to neural mechanisms of executive control functions in a heterogeneous AI community. Fifty-nine self-identified AI participants underwent electroencephalography recordings during a stop signal task and completed measures of social support and spirituality engagement. Event-related potential components indexed attentional resource allocation for inhibitory processing (N2, P3a) and for response error monitoring (error/correct-related negativity; error positivity). Greater social support was linked to attenuated attentional demands for early and sustained inhibitory processing (N2, P3a). Greater Native Spirituality beliefs were linked to greater attentional resources for early but not sustained error-monitoring error-related negativity. Results provide novel evidence for neurocognitive mechanisms of resilience, contribute a deeper understanding of resilience within Indigenous communities, and highlight the role of salient protective factors in mental health that offer a foundation for targeted resilience-based treatment(s). (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Inhibition processing in code-switching among Chinese–English–Japanese trilinguals: Evidence from the n–2 language repetition costs

Aims and Objectives: The current study aimed to investigate whether there was inhibitory processing in code-switching during language comprehension among Chinese–English–Japanese trilinguals and whether n–2 language repetition costs were contingent upon particular stimulus–response configurations. Methodology: This experiment employed semantic categorization tasks, with non-cognate animal and non-animal words as experimental stimuli, and the n–2 language repetition costs as a discerning experimental indicator, to explore whether there was inhibitory processing in code-switching during language comprehension among Chinese–English–Japanese trilinguals. Furthermore, we investigated the impact of stimulus–response configuration on inhibitory processing during switching between phonetic and logographic writing systems. This approach allowed for a detailed exploration of the cognitive mechanisms underpinning language switching and the factors influencing inhibitory control in multilingual contexts. Data and Analysis: The experimental data collected were analyzed using the R language with the lme4 package. Reaction times were fitted to a linear mixed-effects model, while accuracy was binary coded and fitted to a generalized mixed-effects model with a logistic link function. Findings: The study found that: (1) there were n–2 language repetition costs in Chinese–English–Japanese trilinguals’ code-switching during language comprehension and (2) the n–2 language repetition costs in code-switching processing during language comprehension was not affected by specific stimulus–response configurations but was related to the psychological representation of the competing languages. Originality: There is a lack of research investigating the switching of three language tasks using n–2 language repetition costs as an index. Limited studies employing n–2 language repetition costs as an index have predominantly focused on the level of language production, with language comprehension yet to be examined. In addition, there exists a dearth of research addressing the inhibitory mechanisms involved in the code-switching process between phonetic and logographic writing systems; even more limited attention has been directed toward the intricacies of switching between three non-cognate languages. Significance/Implications: The study reveals the inhibitory processing involved in code-switching between phonetic and logographic writing systems. It extends previous findings concerning the inhibitory processing of code-switching during language production within phonetic languages, providing new insights into the research on code-switching and the n–2 language repetition costs among multilingual individuals.

"Actor-critic" dichotomous hyperactivation and hypoconnectivity in obsessive-compulsive disorder.

Dysfunctional response inhibition, mediated by the striatum and its connections, is thought to underly the clinical manifestations of obsessive-compulsive disorder (OCD). However, the exact neural mechanisms remain controversial. In this study, we undertook a novel approach by positing that a) inhibition is a dynamic construct inherently susceptible to numerous failures, which require error-processing, and b) the actor-critic framework of reinforcement learning can integrate neural patterns of inhibition and error-processing in OCD with their behavioural correlates. We invited nineteen adults with OCD and 21 age-matched healthy controls to perform an fMRI-adjusted stop-signal task. Then, we extracted brain activation and connectivity values regarding distinct task phases in the "actor" and "critic" regions, here corresponding to the caudate's head and dorsal putamen, and midbrain's nuclei (ventral tegmental area and substantia nigra). During response preparation phases of the inhibitory process, individuals with OCD exhibited decreased functional connectivity between the "critic" structures and frontal regions involved in cognitive and executive control. Activity analysis revealed task-related hyperactivation in the midbrain alongside error-processing-specific hyperactivation in the striatum, which was correlated with excessive behavioural slowness, also found in the clinical group. Finally, we identified a remarkable opponency between activity in the ventral tegmental area and caudate leading to direct increases and indirect decreases in symptom severity. We propose a unique "actor-critic"-based domain- and timing-dependent neural profile in OCD, reflecting "harm-avoidant" styles for response suppression, and influencing symptom severity. The dichotomy of hypoconnectivity and hyperactivation in the "critic" along with the opponent relationship between the "actor" and the "critic" in determining symptom severity suggests the implication of neural adaptation mechanisms in OCD with potential relevance for neurobiologically-driven therapies.

Executive Functions Assessment in a Child with Autism: A Pilot Single-Case Study from a Longitudinal and Mixed Methods Approach.

This study aimed to assess a pilot program designed to improve the executive functions of a child five years and nine months in age with ASD. To evaluate the effects of the intervention, observational methodology was used, which is considered a mixed method in itself as it integrates both qualitative and quantitative elements in its various phases. Specifically, an idiographic, longitudinal, and multidimensional design was followed. A lag sequential analysis was conducted using GSEQ software Version 5.1, enabling us to study changes in the executive functions of a child before, during, and after the intervention, including whether its effects are sustained over time. The sequential patterns obtained indicate more appropriate and complex executive functioning after the three-month intervention, specifically increased cognitive flexibility, improved self-regulation, more accurate evaluation, and progress in inhibitory processes. However, these improvements do not persist over time. This study contributes to the scarcely explored field of executive function interventions in children with ASD, although it is necessary to consider the generalization of the results to other contexts, such as family and school, during interaction with peers.

The Effect of Physical Activity Interventions on Executive Function in Overweight and Obese Adults: A Systematic Review.

Background/objectives: Overweight and obesity are global public health problems associated with chronic disease and mental health. Physical activity (PA) is essential throughout a person's life; an active lifestyle helps people to live healthier lives and improve their functional and mental abilities, such as executive function (EF). This systematic review aimed to analyze the evidence on the effects of PA on EF in overweight and/or obese adults (≥18 years old). Methods: Records from the PubMed, ScienceDirect, and JSTOR databases were searched and, following the PRISMA guidelines, seven studies were included in the present systematic review. Risk of bias was assessed using the National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results from the studies included indicate that acute, short-term, and long-term PA interventions are an effective strategy to improve inhibitory control, working memory, and processing speed in overweight and obese adults. Furthermore, evidence indicates that EF can be effective as a measure to predict adherence to PA programs and weight loss. Conclusions: Exercise and physical activity interventions are a promising therapeutic strategy to promote weight loss and improve EF in adults with overweight and obesity. Additionally, EF may be further explored as a predictor of healthy aging due to the choices made throughout life and the long-term benefits that result.

Alpha Traveling Waves during Working Memory: Disentangling Bottom-Up Gating and Top-Down Gain Control.

While previous works established the inhibitory role of alpha oscillations during working memory maintenance, it remains an open question whether such an inhibitory control is a top-down process. Here, we attempted to disentangle this issue by considering the spatiotemporal component of waves in the alpha band, i.e., alpha traveling waves. We reanalyzed two pre-existing and open-access EEG datasets (N = 180, 90 males, 80 females, 10 unknown) where participants performed lateralized, visual delayed match-to-sample working memory tasks. In the first dataset, the distractor load was manipulated (2, 4, or 6), whereas in the second dataset, the memory span varied between 1, 3, and 6 items. We focused on the propagation of alpha waves on the anterior-posterior axis during the retention period. Our results reveal an increase in alpha-band forward waves as the distractor load increased, but also an increase in forward waves and a decrease in backward waves as the memory set size increased. Our results also showed a lateralization effect: alpha forward waves exhibited a more pronounced increase in the hemisphere contralateral to the distractors, whereas the reduction in backward waves was stronger in the hemisphere contralateral to the targets. In short, the forward waves were regulated by distractors, whereas targets inversely modulated backward waves. Such a dissociation of goal-related and goal-irrelevant physiological signals suggests the coexistence of bottom-up and top-down inhibitory processes: alpha forward waves might convey a gating effect driven by distractor load, while backward waves may represent direct top-down gain control of downstream visual areas.

Coordination of Pharyngeal and Esophageal Phases of Swallowing.

Although swallowing has been reviewed extensively, the coordination of the phases of swallowing have not. The phases are controlled by the brainstem, but peripheral factors help coordinate the phases. The occurrence, magnitude, and duration of esophageal phase depends upon peripheral feedback activated by the bolus. The esophageal phase does not occur without peripheral feedback from the esophagus. This feedback is mediated by esophageal slowly-adapting mucosal tension receptors through the recurrent and superior laryngeal nerves. A similar reflex mediated by the same peripheral pathway is the activation of swallowing by stimulation of the cervical esophagus. This reflex occurs primarily in human infants and animals, and this reflex may be important for protecting against aspiration after esophago-pharyngeal reflux. Not only are there inter-phase excitatory processes, but also inhibitory processes. A significant inhibitory process is deglutitive inhibition. When one swallows faster than peristalsis ends, peristalsis is inhibited by the new pharyngeal phase. This process prevents the ongoing esophageal peristaltic wave from blocking the bolus being pushed into the esophagus by the new wave. The esophageal phase returns during the last swallow of the sequence. This process is probably mediated by mucosal tension receptors through the superior laryngeal nerves. A similar reflex exists, the pharyngo-esophageal inhibitory reflex, but studies indicate that it is controlled by a different neural pathway. The pharyngo-esophageal inhibitory reflex is mediated by mucosal tension receptors through the glossopharyngeal nerve. In summary, there are significant peripheral processes that contribute to swallowing, whereby one phase of swallowing significantly affects the other.

Lexical inhibition after semantic violations recruits a domain-general inhibitory control mechanism.

Language processing is incremental. As language signals-for example, words in a sentence-unfold, humans predict and activate likely upcoming input to facilitate comprehension. Prediction not only accelerates understanding but also prompts reassessment in the case of prediction error, fostering learning and refining comprehension skills. Therefore, it is paramount to understand what happens when linguistic predictions are violated-for example, when a sentence ends in an unpredicted word. One theory, which we test here, is that the originally predicted word is actively inhibited after semantic violations. Furthermore, we tested whether this purported lexical inhibition process is achieved by a domain-general mechanism-that is, one that also inhibits other processes (e.g., movement). We combined a semantic violation task, in which highly constrained sentences primed specific words but sometimes continued otherwise, with a motoric stop-signal task. Across two experiments, semantic violations significantly impaired simultaneous action-stopping. This implies that lexical and motor inhibition share the same process. In support of this view, multivariate decoding of electroencephalographic recordings showed early overlap in neural processing between action-stopping (motor inhibition) and semantic violations (lexical inhibition). Moreover, a known signature of motor inhibition (the stop-signal P3) was reduced after this initial overlap period, further suggesting the presence of a bottleneck due to shared processing. These findings show that semantic violations trigger inhibitory processing and suggest that this lexical inhibition recruits a domain-general inhibitory control mechanism. This provides a new perspective on long-standing debates in psycholinguistics, extends the range of a well-characterized cognitive control mechanism into the linguistic domain, and offers support for recent neurobiological models of domain-general inhibitory control. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Examining motor evidence for the pause-then-cancel model of action-stopping: insights from motor system physiology.

Stopping initiated actions is fundamental to adaptive behavior. Longstanding, single-process accounts of action-stopping have been challenged by recent, two-process, "pause-then-cancel" models. These models propose that action-stopping involves two inhibitory processes: 1) a fast Pause process, which broadly suppresses the motor system as the result of detecting any salient event, and 2) a slower Cancel process, which involves motor suppression specific to the cancelled action. A purported signature of the Pause process is global suppression, or the reduced corticospinal excitability (CSE) of task-unrelated effectors early on in action-stopping. However, unlike the Pause process, few (if any) motor system signatures of a Cancel process have been identified. Here, we used single- and paired-pulse transcranial magnetic stimulation (TMS) methods to comprehensively measure the local physiological excitation and inhibition of both responding and task-unrelated motor effector systems during action-stopping. Specifically, we measured CSE, short-interval intracortical inhibition (SICI), and the duration of the cortical silent period (CSP). Consistent with key predictions from the pause-then-cancel model, CSE measurements at the responding effector indicated that additional suppression was necessary to counteract Go-related increases in CSE during action-stopping, particularly at later timepoints. Increases in SICI on Stop-signal trials did not differ across task-related and task-unrelated effectors, or across timepoints. This suggests SICI as a potential source of global suppression. Increases in CSP duration on Stop-signal trials were more prominent at later timepoints and were related to individual differences in CSE. Our study provides further evidence from motor system physiology that multiple inhibitory processes influence action-stopping.NEW & NOTEWORTHY Current debate surrounds whether single- or dual-process models better account for human action-stopping ability. We show that motor suppression of a successfully stopped muscle follows a distinct time course compared with when that same muscle is unrelated to the stopping task. Our results further suggest that distinct local inhibitory neuron populations contribute to these unique sources of suppression. Our study provides evidence from motor system physiology that multiple inhibitory processes influence action-stopping.

Stay focused! Exploring the compulsive nature of alcohol-related attentional bias in severe alcohol use disorder.

Prominent models postulate that alcohol-related attentional bias (AB), emerging from the overactivation of the reward system, plays a key role in severe alcohol use disorder (sAUD) and is independent from voluntary control. We determined whether AB is indeed compulsive or can be modulated by the control/inhibition system. Patients with sAUD (17 women, 13 men, mean age of 47, White) and matched healthy controls (16 women, 14 men, mean age of 44, White) performed a visual probe task with behavioral (reaction time) and eye-tracking (first fixation location and duration, second fixation location, dwell time) measures. They also performed an avoidance task, requiring to focus on a target by voluntarily inhibiting eye movements toward alcohol/nonalcohol/nonappetitive distractors and measuring overt (break frequency) and covert (fixational eye movements) attentional processes. Patients with sAUD exhibited an avoidance AB indexed by (a) reduced attentional resources dedicated to alcohol-related stimuli, namely, reduced dwell time (p = .040) and second fixation (p = .001) toward these stimuli; (b) increased inhibitory processes, namely, easier inhibition of saccades toward alcohol measured by lower break frequency (p < .001); and (c) covert eye movements posited further away from alcohol. In contradiction with theoretical models, our two tasks did not show any AB toward alcohol in sAUD. Instead, patients exhibited an avoidance AB indexed by increased inhibitory processes as well as reduced overt and covert attentional resources dedicated to alcohol-related stimuli. These results question the theoretical and clinical role of AB, as measured through reliable eye-tracking tasks, in sAUD. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

High Body Mass Index Disrupts the Homeostatic Effects of Pain Inhibitory Control in the Symptomatology of Patients With Fibromyalgia

This study examines the influence of body mass index (BMI) on the relationship between quantitative sensory testing measures and clinical characteristics in fibromyalgia syndrome (FMS). Utilizing BMI as a categorical covariate (≥25 or ≥30 kg/m²) in associations between quantitative sensory testing metrics (pain-60, conditioned pain modulation, and temporal summation of pain [TSP]) and FMS clinical features, we explored BMI's role as both a confounder (change-in-estimate criterion—change equal or higher than 10%) and effect modifier (interaction term). Significant interactions revealed overweight/obese BMI as a modifier in the relationship between conditioned pain modification and both depression and symptom impact, with a homeostatic relationship between better clinical profile and pain inhibitory response observed solely in the normal-weight group. Similar results were found for pain-60 and depression. Additionally, BMI ≥30 kg/m² modified TSP's effect on pain, demonstrating lower pain with increased TSP, exclusively in the nonobese group. This study highlights the significant role of BMI in moderating the relationships of important pain inhibitory control processes and pain intensity, depression, and the overall impact of FMS symptoms. Our results suggest that high BMI states disrupt the homeostatic effects of pain inhibition, reducing its salutogenic response in FMS participants. We discuss the mechanistic and therapeutic implications of targeting BMI in FMS clinical trials and the potential impact of this important relationship. PerspectiveThis investigation highlights the disruptive influence of high BMI on pain inhibitory control in fibromyalgia, unbalancing clinical symptoms such as pain and depression. It underscores the necessity of integrating BMI considerations into therapeutic approaches to enhance pain management and patient outcomes.

Nightmares in the elderly: Associations with self-reported executive functions

Study objectivesTo describe nightmare phenomenology among community dwelling elderly and to test the hypothesis that reduction in cognitive control is associated with nightmare-related phenomenology including nightmare frequency and severity, greater emotional reactivity, imagery immersion, and dream enactment behaviors (DEBs). MethodsStudy 1: Survey with multiple regression and ANOVAs on N = 56 people with frequent nightmares plus N = 62 age- and gender-matched controls to quantify the strength of the association between cognitive control variables and nightmare phenomenology. Study 2: Computational simulation of nightmare phenomenology in relation to cognitive control to simulate the empirical findings and to assess the underlying causal theory through computationally supported causal inference. ResultsStudy 1: Regressions demonstrated a strong association between reduction in cognitive control and more extreme nightmare phenomenology, including severity, frequency, daytime effects, and DEBs. Study 2: The computational simulation of nightmare phenomenology in relation to cognitive control is validated relative to regressions from study 1 and offers computational support for the causal theory explaining the associations in study 1. ConclusionsIn aging people, decline in executive cognitive functions, cognitive control, and inhibitory processes reduce cognitive control over emotions, thus contributing to unusual nightmare activity, including more extreme nightmare phenomenology such as more severe nightmares, greater emotional reactivity, deeper imagery immersion, and DEBs.

8372 Evidence of dACC Glutamate Modulation During Top-down Inhibitory Control Predicting Weight Loss Ability in Individuals with Obesity Using1H fMRS

Abstract Disclosure: J.M. Eichstaedt: None. R. Sochocki: None. D. Khatib: None. N. Miller: None. V.A. Diwadkar: None. P. Burghardt: None. A.E. Rothberg: None. J.A. Stanley: None. Poor weight loss maintenance (WLM) following dietary intervention has been associated with poor top-down inhibitory control. The neurobiological mechanisms are not fully understood; it is not clear if changes to inhibitory control are specific to the presence of appetitive food cues. The dorsal anterior cingulate cortex (dACC) is central to inhibitory control and can be conceptualized selectively withholding ‘prepotent’ motor responses. This is driven by highly integrated glutamatergic and GABAergic neurotransmission. Temporal changes in glutamate, reflecting shifts in glutamate neurotransmission, can be detected under distinct processes or task conditions using [1]H fMRS. We investigated differences in dACC glutamate under task conditions with or without inhibitory motor control, utilizing neutral Squares and Food/Non-food stimuli, and their association with weight loss. Data were acquired from 13 individuals with obesity following dietary intervention resulting in 10% weight loss (5F; mean age: 50.1±5.2yrs). A visually-guided motor tapping task was used requiring participants to respond to stimuli under two modes, “Non-Selective” (motor responses to 100% of trials) and “Selective” (withholding responses on 20% of trials - involving both motor control and inhibition), and under two stimuli types (Squares and appetitive Food/Non-Food cues). Glutamate modulation changes (relative to the total signal) were assessed across stimuli type (independent of task mode) using repeated measures generalizing estimating equations (GEE) approach (SAS GENMOD). The correlation between glutamate during the Selective mode with food/non-food stimuli and percentage of weight lost during the dietary intervention was also assessed. The stimuli model term was not significant (χ2=3.50, p=0.174), but post hoc analysis indicated significantly increased glutamate during the Squares (z=-1.99, p=0.046), but not the Food/Non-food (z=-1.39, p=0.163) relative to baseline. A trending correlation between decreasing dACC glutamate modulation (Selective mode, Food/Non-Food) and decreasing percentage of weight lost during the intervention was observed (R2=0.274, F(1,11)=4.15, p=0.07). This suggests that the presence of appetitive food cues leads to a non-significant change in the dACC glutamate modulation independent of inhibitory or motor alone responses. The potential correlation between dACC glutamate modulation and weight loss provides preliminary support that appetitive food cues influence inhibitory control and the extent of the influences may be related to one’s ability to maintain weight loss. These results could provide greater understanding of the neurobiological mechanisms underlying top-down inhibitory processes influenced by affect and difficulties with weight loss and maintenance, potentially fueling better treatment for successful long-term WLM in obesity. Presentation: 6/1/2024

Distinct Inhibitory Control Mechanisms Underlie Selective Social Inferences

ABSTRACT We investigated the role of distinct inhibitory processes as 4- to 6-year-olds from the Northeastern United States (N = 48, Mage = 68.27 months, 22 boys, 26 girls; 63% White, 6% Black, 4% Asian, 2% Hispanic, 8% more than one race, with 17% not reporting) and adults evaluated accurate or deceptive information from human or non-human (arrow) cues indicating particular locations in space. We achieved this by tracking the trajectories of our participants’ manual responses in 3D space over time. This approach allowed us to isolate inhibitory mechanisms that monitor for conflict between stimuli and representations from inhibitory mechanisms that resolve that conflict to make a response. Regardless of the cue’s accuracy, the participants we tested needed more inhibitory resources to monitor human cues that indicated the location of a hidden object than arrows. The inhibitory resources the children we tested needed to control their response (i.e., respond where the cue was pointing when it was accurate or respond alternatively when it was deceptive) was stable across the trials when the cue was a human pointing. When it was an arrow, older children needed fewer resources. These data suggest that there is continuity in participants' use of the resources necessary to monitor human information for deception, but development in the resources needed to resolve such information when learning selectively.

Concentration‐Dependent Thermodynamics of the Inhibitory Paths in Homogeneous Mn(I) Hydrogenation Catalysis

AbstractMany catalytic reactions suffer from product inhibition, which especially hard to control in homogeneous hydrogenation due to the scaling relation between the inhibited and active states of the catalyst. We recently reported one such pathway in Mn(I) hydrogenation and demonstrated that addition of alkoxide bases could affect the thermodynamic favorability of this reaction and selectively suppress the product inhibition. Since external reaction promotors are formally not involved in reaction thermodynamics, we set to investigate the explicit molecular interactions behind these apparently environmental effects. Herein, we reveal that the thermodynamic landscape of the inhibitory process exhibits a non‐monotonic dependence on the base concentration. This study related this phenomenon to the presence of two dominant mechanisms operating at different base concentrations. Specifically, the base additives can enhance the ionic strength and lower the free energy of the inhibited state at low promotor concentration. At high base concentrations this study suggested the formation of highly labile alcohol‐alkoxide clusters which stabilize the free alcohol and make its addition to the catalyst unfavourable, thereby suppressing the inhibition. While relatively weak, such noncovalent interactions between reactants and reaction environment can cause substantial perturbations to the free energy of catalytic process, ultimately deciding its fate.

Do changes in cerebral blood flow modulate the amplitudes of P300 during cognitive task?

A single session of aerobic or resistance training transiently enhances cognitive function, making it a valuable strategy for dementia prevention in the older people. Despite its acknowledged benefits, the precise mechanism behind exercise-induced cognitive improvement remains controversial. In the present study, we investigated the impact of altered cerebral blood flow (CBF) on brain neural activity originating from motor executive and inhibitory processing using electroencephalographic event-related potentials (EEG-ERPs). Sixteen healthy subjects participated in four sessions, with EEG-ERPs measured during somatosensory Go/No-go tasks. The sessions were conducted under four distinct respiratory conditions presented in random order: normal breathing (NB) and rapid breathing (RB) with room air, normal breathing with hypercapnic gas (5% CO2, 21% O2, and balanced N2) (NB+Gas), and rapid breathing with the same gas (RB+Gas). Changes in CBF were evaluated based on the middle cerebral artery mean blood velocity (MCA Vmean) using transcranial Doppler. PETCO2 was decreased under the RB condition but increased under the NB+Gas condition, thereby decreasing and increasing MCA Vmean, respectively. Under the NB+Gas condition, MCA Vmean significantly increased, but it had no effect on either the executive or inhibitory function. In contrast, the reduction in MCA Vmean induced by RB decreased the peak amplitudes of Go-P300 and No-go-P300. However, even under the RB+Gas condition while MCA Vmean increased, the peak amplitudes of both also decreased. These findings suggest that neither increases nor decreases in CBF affected cognitive function.

Medial Prefrontal Cortex Stimulation Reduces Retrieval-Induced Forgetting via Fronto-parietal Beta Desynchronization.

The act of recalling memories can paradoxically lead to the forgetting of other associated memories, a phenomenon known as retrieval-induced forgetting (RIF). Inhibitory control mechanisms, primarily mediated by the prefrontal cortex, are thought to contribute to RIF. In this study, we examined whether stimulating the medial prefrontal cortex (mPFC) with transcranial direct current stimulation modulates RIF and investigated the associated electrophysiological correlates. In a randomized study, 50 participants (27 males and 23 females) received either real or sham stimulation before performing retrieval practice on target memories. After retrieval practice, a final memory test to assess RIF was administered. We found that stimulation selectively increased the retrieval accuracy of competing memories, thereby decreasing RIF, while the retrieval accuracy of target memories remained unchanged. The reduction in RIF was associated with a more pronounced beta desynchronization within the left dorsolateral prefrontal cortex (left-DLPFC), in an early time window (<500 ms) after cue onset during retrieval practice. This led to a stronger beta desynchronization within the parietal cortex in a later time window, an established marker for successful memory retrieval. Together, our results establish the causal involvement of the mPFC in actively suppressing competing memories and demonstrate that while forgetting arises as a consequence of retrieving specific memories, these two processes are functionally independent. Our findings suggest that stimulation potentially disrupted inhibitory control processes, as evidenced by reduced RIF and stronger beta desynchronization in fronto-parietal brain regions during memory retrieval, although further research is needed to elucidate the specific mechanisms underlying this effect.