Is precrastination related to updating and inhibition aspects of executive function?

ABSTRACTPrecrastination is the act of completing a task as soon as possible even at the expense of extra effort. Past research has suggested that individuals precrastinate due to a desire to reduce their cognitive load, also known as the cognitive load-reduction (CLEAR) hypothesis [VonderHaar, R. L., McBride, D. M., & Rosenbaum, D. A. (2019). Task order choices in cognitive and perceptual-motor tasks: The cognitive-load-reduction (CLEAR) hypothesis. Attention, Perception, & Psychophysics, 81(7), 2517-2525. https://doi.org/10.3758/s13414-019-01754-z]. This idea stems from the notion that it is taxing to hold intentions in working memory and completing a task as soon as possible releases cognitive resources for other tasks. Based on this hypothesis, we predicted that aspects of executive function may play a role in precrastination. We tested this prediction using a box-moving task developed in a previous study to measure precrastination. We also incorporated tasks measuring updating and inhibition aspects of executive function: the Stroop interference (both experiments) and Simon tasks (Experiment 2) to measure inhibition and the 2-Back memory task (Experiment 1) to measure updating. We found that the majority of participants precrastinated significantly throughout the box-moving task trials, consistent with results from past studies. However, no relation was found between the executive function tasks and rates of precrastination. These results may be due to the automaticity of precrastination when cognitive resources are limited.

Inhibition moderates the effect of attentional bias modification for reducing residual depressive symptoms: A randomized sham-controlled clinical trial.

OBJECTIVES: Residual symptoms represent risk factor for relapse. Attention bias modification (ABM) may reduce clinical and sub-clinical depressive symptoms, indicating that is may be of relevance when preventing relapse. Current evidence suggests that executive functions may moderate the outcome of interventions targeting depressive symptoms. METHODS: We assessed inhibition and shifting as indicators of executive functioning by means of the Color-Word Interference Test (i.e., "Stroop task"). These baseline characteristics were investigated as moderator of the effect of ABM on depression symptoms in a double-blinded randomized sham-controlled trial of ABM including patients with a history of recurrent depression (N = 301). Inclusion and follow-ups took place from January 2015 to October 2016. The trial was retrospectively registered #NCT02658682 January 2016. RESULTS: The moderation analysis was based on the interaction term ABM x Stroop. Scaled inhibition scores ≤10.8, but not shifting ability, moderated the effect of ABM compared to sham on clinician-rated depression (HDRS). The difference from the 15th to the 85th percentile of the inhibition score was about 1 HDRS-point, indicating a small effect size. No moderation was found when self-reported depression and AB were the outcome. Post-hoc power calculation indicates risk of Type-II error. CONCLUSION: When targeting depressive symptoms, ABM seems to be somewhat more effective in patients with weak inhibitory control. This suggests that evaluating the level of inhibition in individual patients could provide some information when making decisions about prescribing ABM to reduce residual symptoms, but the clinical implications of this is uncertain due to an overall small effect size attributable to ABM. Future studies should examine whether inhibitory control still is a relevant moderator when comparing ABM to treatment options other than the sham control condition.

The link between executive skills and neural dynamics during encoding, inhibition, and retrieval of visual information in the elderly.

During aging the inter-individual variability in both the neural and behavioral functions is likely to be emphasized. Decreased competence particularly in working memory and general executive control compromises many aspects of the quality of life also within the nonclinical population. We aimed, first, to clarify the brain basis of visual working memory and inhibition during multi-stage natural-like task performance, and second, to identify associations between variation in task-related neural activity and relevant cognitive skills, namely inhibition and general working memory capacity. We recorded, using magnetoencephalography (MEG), the neural modulations associated with encoding, maintenance, and retrieval, as well as interference suppression during a visual working memory task in older adults. We quantified the neural correlates of these cognitive processes through two complementary approaches: evoked responses and oscillatory activity. Neural activity during memory retrieval and interference suppression were correlated with behavioral measures of task switching and general executive functions. Our results show that general inhibitory control induced frontocentral neural modulation across a broad range of frequencies whereas domain-specific inhibition was limited to right posterior areas. Our findings also suggest that modulations particularly in phase-locked evoked neural activity can be reliably associated with explicit measures of cognitive skills, with better inhibitory control linked with an early neural effect of distractor inhibition during retrieval. In general, we show that exploiting the inherent inter-individual variability in neural measures and behavioral markers of cognition in aging populations can help establish reliable links between specific brain functions and their behavioral manifestations.

Direct serotonin release in humans shapes aversive learning and inhibition.

The role of serotonin in human behaviour is informed by approaches which allow in vivo modification of synaptic serotonin. However, characterising the effects of increased serotonin signalling in human models of behaviour is challenging given the limitations of available experimental probes, notably selective serotonin reuptake inhibitors. Here we use a now-accessible approach to directly increase synaptic serotonin in humans (a selective serotonin releasing agent) and examine its influence on domains of behaviour historically considered core functions of serotonin. Computational techniques, including reinforcement learning and drift diffusion modelling, explain participant behaviour at baseline and after week-long intervention. Reinforcement learning models reveal that increasing synaptic serotonin reduces sensitivity for outcomes in aversive contexts. Furthermore, increasing synaptic serotonin enhances behavioural inhibition, and shifts bias towards impulse control during exposure to aversive emotional probes. These effects are seen in the context of overall improvements in memory for neutral verbal information. Our findings highlight the direct effects of increasing synaptic serotonin on human behaviour, underlining its role in guiding decision-making within aversive and more neutral contexts, and offering implications for longstanding theories of central serotonin function.

The proactive and reactive mechanisms of learned spatial suppression.

Selection history refers to the notion that previous allocations of attention or suppression have the potential to elicit lingering and enduring selection biases that are isolated from goal-driven or stimulus-driven attention. However, in the singleton detection mode task, manipulating the selection history of distractors cannot give rise to pure proactive inhibition. Therefore, we employed a combination of a working memory task and a feature search mode task, simultaneously recording cortical activity using EEG, to investigate the mechanisms of suppression guided by selection history. The results from event-related potential and reaction times showed an enhanced inhibitory performance when the distractor was presented at the high-probability location, along with instances where the target appeared at the high-probability location of distractors. These findings demonstrate that a generalized proactive inhibition bias is learned and processed independent of cognitive resources, which is supported by selection history. In contrast, reactive rejection toward the low-probability location was evident through the Pd component under varying cognitive resource conditions. Taken together, our findings indicated that participants learned proactive inhibition when the distractor was at the high-probability location, whereas reactive rejection was involved at low-probability location.

Enhancing response inhibition behavior through tDCS intervention in college students with smartphone addiction.

Smartphone addiction, emerging from excessive use of smartphones, poses a challenge to inhibitory control functions within society. This research employed transcranial direct current stimulation (tDCS) as an intervention alongside the stop signal task (SST) to explore behavioral distinctions between individuals with smartphone addiction and a non-addicted control group, focusing on the efficacy of tDCS intervention. The participant cohort comprised 80 individuals, divided into an addiction group (39 participants, with 19 receiving active tDCS and 20 receiving sham tDCS) and a control group (41 participants, with 20 receiving active tDCS and 21 receiving sham tDCS), with anodal stimulation applied over the right dorsolateral prefrontal cortex (dlPFC) and cathodal placement over the left arm. The findings indicate that university students struggling with smartphone addiction exhibit reduced inhibitory control compared to their non-addicted peers, while maintaining similar levels of general cognitive control. Remarkably, tDCS interventions were observed to enhance inhibitory control in both groups. Although the improvement in the addiction group appeared more pronounced numerically than in the control group, no significant interaction with group was noted. However, a higher percentage of participants in the smartphone addiction (SA) group exhibited enhanced response inhibition under active tDCS. This study demonstrates the inhibitory control deficits in individuals addicted to smartphones and underscores the potential of tDCS in enhancing response inhibition. It provides a valuable reference for future tDCS research targeting smartphone addiction and highlights the importance of developing healthier smartphone usage habits.

Meta-analysis of variance in tDCS effects on response inhibition.

Deficiencies in response inhibition are associated with numerous mental health conditions, warranting innovative treatments. Transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, modulates cortical excitability and has shown promise in improving response inhibition. However, tDCS effects on response inhibition often yield contradictory findings. Previous research emphasized the importance of inter-individual factors that are mostly ignored in conventional meta-analyses of mean effects. We aimed to fill this gap and promote the complementary use of the coefficient of variation ratio and standardized mean effects. The systematic literature search included single-session and sham-controlled tDCS studies utilizing stop-signal task or Go-NoGo tasks, analyzing 88 effect sizes from 53 studies. Considering the impact of inter-individual factors, we hypothesized that variances increase in the active versus sham tDCS. However, the results showed that variances between both groups did not differ. Additionally, analyzing standardized mean effects supported previous research showing an improvement in the stop-signal task but not in the Go-NoGo task following active tDCS. These findings suggest that inter-individual differences do not increase variances in response inhibition, implying that the heterogeneity cannot be attributed to higher variance in response inhibition during and after active tDCS. Furthermore, methodological considerations are crucial for tDCS efficacy.

Monetary reward enhances response inhibition processes manifested in No-go P3.

This study investigated the impact of motivational valence on No-go P3 and N2 by incorporating monetary rewards based on response outcomes. We also investigated how personality differences in terms of the behavioral inhibition system (BIS) and behavioral approach system (BAS) influenced No-go N2 and No-go P3. Twenty-eight participants performed Go/No-go tasks (80 % Go and 20 % No-go) under two conditions. In the reward condition, each correct-rejection trial for the No-go stimulus was rewarded with 10 yen (∼6 cents), whereas in the neutral condition, neither monetary rewards nor punishments were contingent on response outcomes. Individual responsiveness to punishment and rewards was evaluated using the BIS and BAS scales. The error rate was significantly lower in the reward condition than in the neutral condition. P3 amplitude for correct-rejection trials (i.e., preceding erroneous muscular activity on the wrong hand) was larger in the reward condition than in the neutral condition; however, N2 amplitudes did not differ between the two conditions. These results suggest that monetary rewards may enhance motor inhibition control. Individuals with a higher BIS score exhibited a larger No-go N2 for correct-rejection in the neutral condition. We conclude that No-go N2 amplitude is modulated by avoidance motivation.

Aggressiveness, inhibitory control, and emotional states: A provocation paradigm.

The current study examines the effects of trait aggressiveness, inhibitory control and emotional states on aggressive behavior in a laboratory paradigm. One hundred and fifty-one adult participants took part (73 men, 71 women, and 7 nondisclosed). Event Related Potentials (ERPs) during a Go/No-Go task were utilized to capture the extent of inhibitory processing, with a laboratory provocation paradigm used to assess aggression. Contrary to the expectations, negative affective responses to provocation were negatively associated only with short-lived aggression and only among those with high past aggressiveness. Furthermore, past aggressiveness was related to a continuous increase in laboratory aggressive behavior regardless of the level of inhibitory control (P3 difference amplitude). However, feeling hostile was associated with short-lived aggressive behavior, only in those with lower levels of inhibitory control. These findings demonstrate the effect of distinct mechanisms on different patterns of aggressive behavior.

Effects of 9 Weeks of High- or Moderate-Intensity Training on Cardiorespiratory Fitness, Inhibitory Control, and Plasma Brain-Derived Neurotrophic Factor in Danish Adolescents-A Randomized Controlled Trial.

PURPOSE: The primary aims of this study were to examine the effects of 9 weeks of aerobic training, comprising three 30-min sessions per week, on V̇O2max, inhibitory control, and plasma brain-derived neurotrophic factor (BDNF) levels among adolescents aged 16-19 years. METHODS: One hundred twenty-one untrained or recreationally active adolescents from a Danish high school were enrolled in the study, with 58 females (17.8 ± 0.8 years) and 27 males (18.0 ± 0.9 years) completing it. Participants were randomly divided into three groups performing aerobic training at either moderate-intensity (MIT: 60%-70% heart rate reserve [HRR]) or high-intensity (HIT: 80%-100% HRR) or a passive control group (CON) continuing their habitual lifestyle. Both the training groups exercised for 3×30 min per week for 9 weeks using a combination of cycling and running. Before and after the intervention period maximal oxygen uptake (V̇O2max) and the primary outcomes (inhibitory control measured by a modified flanker task, and resting plasma levels of BDNF) were evaluated. RESULTS: After the intervention period, the HIT group demonstrated a larger increase in V̇O2max compared to both the CON and MIT groups, while no significant effects were observed on inhibitory control or plasma BDNF levels in any training group. However, compared to the CON group, the HIT group exhibited a tendency for greater improvement in the flanker interference score (accuracy), attributable to enhanced accuracy on the incongruent stimuli from pre to post. CONCLUSION: Aerobic training in adolescents increased cardiorespiratory fitness in an intensity-dependent manner, but no clear effects were observed on neither inhibitory control nor resting plasma BDNF levels. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02075944.

Motor inhibition errors and interference suppression errors differ systematically on neural and behavioural features of response monitoring.

Action inhibition and error commission are prominent in everyday life. Inhibition comprises at least two facets: motor inhibition and interference suppression. When motor inhibition fails, a strong response impulse cannot be inhibited. When interference suppression fails, we become distracted by irrelevant stimuli. We investigated the neural and behavioural similarities and differences between motor inhibition errors and interference suppression errors systematically from stimulus-onset to post-response adaptation. To enable a direct comparison between both error types, we developed a complex speeded choice task where we assessed the error types in two perceptually similar conditions. Comparing the error types along the processing stream showed that the P2, an early component in the event-related potential associated with sensory gating, is the first marker for differences between the two error types. Further error-specific variations were found for the parietal P3 (associated with context updating and attentional resource allocation), for the lateralized readiness potential (LRP, associated with primary motor cortex activity), and for the Pe (associated with error evidence accumulation). For motor inhibition errors, the P2, P3 and Pe tended to be enhanced compared to successful inhibition. The LRP for motor inhibition errors was marked by multiple small response impulses. For interference suppression errors, all components were more similar to those of successful inhibition. Together, these findings suggest that motor inhibition errors arise from a deficient early inhibitory process at the perceptual and motor level, and become more apparent than interference suppression errors, that arise from an impeded response selection process.

Neural and behavioral markers of inhibitory control predict symptom improvement during internet-delivered cognitive behavioral therapy for depression.

Poor inhibitory control contributes to deficits in emotion regulation, which are often targeted by treatments for major depressive disorder (MDD), including cognitive behavioral therapy (CBT). Brain regions that contribute to inhibitory control and emotion regulation overlap; thus, inhibitory control might relate to response to CBT. In this study, we examined whether baseline inhibitory control and resting state functional connectivity (rsFC) within overlapping emotion regulation-inhibitory control regions predicted treatment response to internet-based CBT (iCBT). Participants with MDD were randomly assigned to iCBT (N = 30) or a monitored attention control (MAC) condition (N = 30). Elastic net regression was used to predict post-treatment Patient Health Questionnaire-9 (PHQ-9) scores from baseline variables, including demographic variables, PHQ-9 scores, Flanker effects (interference, sequential dependency, post-error slowing), and rsFC between the dorsal anterior cingulate cortex, bilateral anterior insula (AI), and right temporoparietal junction (TPJ). Essential prognostic predictor variables retained in the elastic net regression included treatment group, gender, Flanker interference response time (RT), right AI-TPJ rsFC, and left AI-right AI rsFC. Prescriptive predictor variables retained included interactions between treatment group and baseline PHQ-9 scores, age, gender, Flanker RT, sequential dependency effects on accuracy, post-error accuracy, right AI-TPJ rsFC, and left AI-right AI rsFC. Inhibitory control and rsFC within inhibitory control-emotion regulation regions predicted reduced symptom severity following iCBT, and these effects were stronger in the iCBT group than in the MAC group. These findings contribute to a growing literature indicating that stronger inhibitory control at baseline predicts better outcomes to psychotherapy, including iCBT.

Modality Matters: Fasted Individuals Inhibit Food Stimuli Better Than Neutral Stimuli for Words, but Not for Pictures.

The current study aimed to evaluate the effect different modalities (pictures and words) of food stimuli have on inhibitory control under different homeostatic states. To this end, the homeostatic state was altered by asking participants to fast for 16 h (n = 67) or eat lunch as usual (n = 76) before completing an online stop-signal task with modal (pictures) and amodal (words) food and valenced-matched non-food stimuli. The inclusion of non-food stimuli allowed us to test the food specificity of the effect. We found a significant Group × Modality × Stimulus Type interaction (F(1,141) = 5.29, p = 0.023, ηp2 = 0.036): fasted individuals had similar inhibitory capacity for modal and amodal food stimuli but better inhibitory capacity for non-food words compared to images, while there were no inhibitory differences in dependence on either modality or stimulus type in satiated individuals. Thus, we were able to show that inhibitory capacities to modal compared to amodal stimuli depend on participants' current state of fasting. Future studies should focus on how this lowered inhibitory capacity influences food intake, as well as the role of stimulus valence in cognitive processing, to clarify potential implications for dieting and weight loss training.

Whole Coffee Cherry Extract Improves Working Memory and Response Inhibition: Acute and Longitudinal Results from a Remote, Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

Earlier laboratory-based evidence has suggested that polyphenol-rich, decaffeinated whole coffee cherry extract (CCE) supports improvements in acute and long-term cognitive performance. To better understand CCE's potential to promote cognitive processing, we conducted a first-of-its-kind remote clinical trial. Participants were randomized into one of two intervention arms: placebo or 200 mg CCE. At the beginning of the study, participants were asked to complete a set of acute cognitive challenges as part of the baseline assessment. Tasks were nearly identical to those used in previous, laboratory-based research. Acute results support that CCE outperformed placebo, reducing omissions and improving accuracy, during working memory and inhibitory control tasks. Long-term results indicate that CCE outperformed placebo on a measure of accuracy. This contributes to the literature in three ways: (1) results improve upon previously reported robust and consistent findings in a real-world setting that a single-dose of CCE acutely improved cognitive performance; (2) results replicate previous laboratory findings but in a real-world setting that long-term CCE supplementation outperformed placebo on measures of accuracy in a working memory task; and (3) it serves as proof of concept of a novel remote clinical trial model that may provide real-world evidence of efficacy while increasing accessibility and cohort diversity.

Morphological and Inhibitory Skills in Monolingual and Bilingual Children With and Without Developmental Language Disorder.

PURPOSE: This study examined the language and nonverbal inhibitory control skills of Italian monolingual and bilingual typically developing (TD) preschoolers with Italian as their second language and of age-matched monolingual and bilingual peers with developmental language disorder (DLD). METHOD: Four groups of preschoolers were enrolled: 30 TD Italian monolinguals, 24 TD bilinguals, 19 Italian monolinguals with DLD, and 19 bilinguals with DLD. All children were assessed in Italian on vocabulary, receptive morphosyntax, and morphological markers for DLD in the Italian language (i.e., third-person verb inflections, definite articles, third-person direct-object clitic pronouns, simple prepositions) and nonverbal inhibitory control skills. Group performance was compared using a series of one-way analyses of variance. RESULTS: Monolingual and bilingual children with DLD achieved significantly lower performance in all language measures compared to both TD monolingual and bilingual children. However, TD bilinguals, although comprehensively showing better language skills than monolinguals with DLD, achieved a performance closer to that of monolinguals with DLD but significantly higher than that of bilinguals with DLD. Both TD monolinguals and bilinguals showed better results than both DLD groups in inhibitory control tasks, particularly in the interference suppression task. CONCLUSIONS: This study provides a picture of language and inhibitory control characteristics of children with various language profiles and adds to the literature on potential markers of DLD among bilingual children. These results suggest that the assessment of nonlinguistic markers, which are associated with language impairment, could be a useful approach to better specify the diagnosis of DLD and reduce cases of misdiagnosis in the context of bilingualism.

Evidence of bottom-up homeostatic modulation induced taVNS during emotional and Go/No-Go tasks.

Bilateral transcutaneous auricular vagus nerve stimulation (taVNS) - a non-invasive neuromodulation technique - has been investigated as a safe and feasible technique to treat many neuropsychiatric conditions. such as epilepsy, depression, anxiety, and chronic pain. Our aim is to investigate the effect of taVNS on neurophysiological processes during emotional and Go/No-Go tasks, and changes in frontal alpha asymmetry. We performed a randomized, double-blind, sham-controlled trial with 44 healthy individuals who were allocated into two groups (the active taVNS group and the sham taVNS group). Subjects received one session of taVNS (active or sham) for 60 min. QEEG was recorded before and after the interventions, and the subjects were assessed while exposed to emotional conditions with sad and happy facial expressions, followed by a Go/No-Go trial. The results demonstrated a significant increase in N2 amplitude in the No-Go condition for the active taVNS post-intervention compared to the sham taVNS after adjusting by handedness, mood, and fatigue levels (p = 0.046), significantly reduced ERD during sad conditions after treatment (p = 0.037), and increased frontal alpha asymmetry towards the right frontal hemisphere during the emotional task condition (p = 0.046). Finally, we observed an interesting neural signature in this study that suggests a bottom-up modulation from brainstem/subcortical to cortical areas as characterized by improved lateralization of alpha oscillations towards the frontal right hemisphere, and changes in ERP during emotional and Go/No-Go tasks that suggests a better subcortical response to the tasks. Such bottom-up effects may mediate some of the clinical effects of taVNS.

Intrinsic Infant Hippocampal Function Supports Inhibitory Processing.

Impaired cerebral inhibition is commonly observed in neurodevelopmental disorders and may represent a vulnerability factor for their development. The hippocampus plays a key role in inhibition among adults and undergoes significant and rapid changes during early brain development. Therefore, the structure represents an important candidate region for early identification of pathology that is relevant to inhibitory dysfunction. To determine whether hippocampal function corresponds to inhibition in the early postnatal period, the present study evaluated relationships between hippocampal activity and sensory gating in infants 4-20 weeks of age (N = 18). Resting-state functional magnetic resonance imaging was used to measure hippocampal activity, including the amplitude of low-frequency fluctuations (ALFFs) and fractional ALFF. Electroencephalography during a paired-stimulus paradigm was used to measure sensory gating (P50). Higher activity of the right hippocampus was associated with better sensory gating (P50 ratio), driven by a reduction in response to the second stimulus. These findings suggest that meaningful effects of hippocampal function can be detected early in infancy. Specifically, higher intrinsic hippocampal activity in the early postnatal period may support effective inhibitory processing. Future work will benefit from longitudinal analysis to clarify the trajectory of hippocampal function, alterations of which may contribute to the risk of neurodevelopmental disorders and represent an intervention target.

Longitudinal relations among temperament, cognitive control, and anxiety: From toddlerhood to late adolescence.

Children with a history of behaviorally inhibited (BI) temperament face a heightened risk for anxiety disorders and often use control strategies that are less planful. Although these relations have been observed concurrently in early childhood, middle childhood, and adolescence, few studies leverage longitudinal data to examine long-term prospective relations between cognitive control and anxiety. Using longitudinal data from 149 adolescents (55% female; from predominantly White middle-class families), we assessed temperament in toddlerhood and cognitive control and anxiety at 4, 12, 15, and 18 years of age. At age 4, separate measures of task switching and inhibitory control were obtained via the Dimensional Change Card Sort and Stroop tasks, respectively. At 12, 15, and 18 years of age, planful control was assessed with the AX-Continuous Performance Test, and anxiety symptoms were assessed via self-report. Growth curve models revealed that children with greater inhibitory control at age 4, regardless of BI status, experienced a sharper increase in anxiety symptoms across adolescence. Children with heightened BI during early childhood displayed lower levels of planful control at age 12, but experienced a more rapid improvement in these skills across adolescence. Children with greater task switching ability at age 4 displayed higher levels of planful control at age 12, but experienced a smaller increase in these skills across adolescence. Finally, children's growth rate for anxiety was unrelated to their growth rate for planful control. These findings reveal that early-life temperament, cognitive control, and anxiety remain interconnected across development, from toddlerhood to at least late adolescence. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Action plan discarding leads to unbinding of action features.

Action planning can be construed as the temporary binding of action features to form a representation known as an action file. This file is distinct from other possible, but currently not required actions of the behavioral repertoire. To further this action file approach, we investigated what happens with an initially planned action, which however, is discarded before execution. In two experiments we found consistent evidence for a quick unbinding of action features with discarding. Other possible mechanisms that action discarding might invoke, be it the paradox strengthening of a discarded action plan, the selective suppression of the otherwise intact plan, or the global suppression of all subsequent action, were not or at least less consistently supported. These findings provide a novel perspective on inhibitory action control, which we discuss with respect to its applications to other instances of such inhibitory control as studied in multitasking, stop-signal, directed forgetting, or response-reprogramming paradigms. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Additive effects of depression and obesity on neural correlates of inhibitory control.

BACKGROUND: Depression and obesity are associated with impaired inhibitory control. Behavioral evidence indicates an exacerbating additive effect when both conditions co-occur. However, the underlying neural mechanisms remain unclear. Moreover, systemic inflammation affects neurocognitive performance in both individuals with depression and obesity. Here, we investigate additive effects of depression and obesity on neural correlates of inhibitory control, and examine inflammation as a connecting pathway. METHODS: We assessed inhibitory control processing in 64 individuals with obesity and varying degrees of depressed mood by probing neural activation and connectivity during an fMRI Stroop task. Additionally, we explored associations of altered neural responses with individual differences in systemic inflammation. Data were collected as part of the BARICO (Bariatric surgery Rijnstate and Radboudumc neuroimaging and Cognition in Obesity) study. RESULTS: Concurrent depression and obesity were linked to increased functional connectivity between the supplementary motor area and precuneus and between the inferior occipital and inferior parietal gyrus. Exploratory analysis revealed that circulating inflammation markers, including plasma leptin, IL-6, IL-8, and CCL-3 correlated with the additive effect of depression and obesity on altered functional connectivity. LIMITATIONS: The observational design limits causal inferences. Future research employing longitudinal or intervention designs is required to validate these findings and elucidate causal pathways. CONCLUSION: These findings suggest increased neural crosstalk underlying impaired inhibitory control in individuals with concurrent obesity and depressed mood. Our results support a model of an additive detrimental effect of concurrent depression and obesity on neurocognitive functioning, with a possible role of inflammation.