Stroop Task Research Articles

A Sense of Urgency on the Sense of Agency: Challenges in Evaluating Agency and Embodiment in Virtual Reality.

Control over an avatar in virtual reality can improve one's perceived sense of agency and embodiment towards their avatar. Yet, the relationship between control on agency and embodiment remains unclear. This work aims to investigate two main ideas: (1) the effectiveness of currently used metrics in measuring agency and embodiment and (2) the relationship between different levels of control on agency, embodiment, and cognitive performance. To do this, we conducted a between-participants user study with three conditions on agency ($\mathrm{n}=57$). Participants embodied an avatar with one of three types of control (i.e., Low - control over head only, Medium - control over head and torso, or High - control over head, torso, and arms) and completed a Stroop test. Our results indicate that the degree of control afforded to participants impacted their embodiment and cognitive performance but, as expected, could not be detected in the self-reported agency scores. Furthermore, our results elucidated further insights into the relationship between control and embodiment, suggesting potential uncanny valley-like effects. Future work should aim to refine agency measures to better capture the effect of differing levels of control and consider other methodologies to measure agency.

Cognitive deficits’ profiles of attention and executive functions in epilepsy versus psychogenic non-epileptic seizure patients: A preliminary cross-sectional study

Psychogenic non-epileptic seizures (PNES) resemble epileptic seizures (ES) but lack the associated brain electrical disruptions. Their underlying mechanism remains elusive, even though cognitive deficits are commonly reported in both ES and PNES patients. This preliminary cross-sectional study compared attention and executive functions in 20 patients with ES (ES group) and 18 with PNES or comorbid PNES and ES (PNES group) using the Stroop task and attentional network task (ANT). Both groups exhibited a significant Stroop effect, with no significant differences between them. In the ANT assessment, the ES group had significantly slower reaction times (RTs) in non-tone conditions compared to in-tone conditions (P < 0.05). Meanwhile, the PNES group displayed no significant difference in RTs between these conditions, indicating a more pronounced alerting effect in the ES compared to PNES group. No significant disparities emerged in executive control and orientation between the groups. The findings underscore differences in attentional processing between these groups, emphasizing the clinical significance of understanding these cognitive deficits for accurate diagnosis and tailored neuropsychological rehabilitation.

Effectiveness of Korean medicine treatments in improving cognitive function and prefrontal cortex activity in older individuals with mild cognitive impairment: retrospective observational study.

Mild cognitive impairment (MCI) is a growing concern among older adults, with limited effective pharmacological treatments available. Despite the potential of herbal medicine and acupuncture in managing MCI, there is a lack of research on their long-term effects on cognitive function and brain activity in clinical practice settings. This study aimed to address this gap by exploring the effects of a community-based program integrating herbal medicine and acupuncture on cognitive function and neural responses in older individuals with MCI. Nineteen individuals were enrolled from a pool of 250 individuals registered in the 2021 Busan Dementia Prevention & Care Program. Participants with MCI received herbal medicine, acupuncture, and pharmacopuncture treatments over a 6-month period. The Montreal Cognitive Assessment (MoCA) was administered at baseline and after 3 and 6 months to evaluate cognitive function. Functional near-infrared spectroscopy (fNIRS) was used to measure prefrontal cortex activity during cognitive task performance, including verbal fluency, Stroop color and word, and digit span backward tests. Seventeen participants (13 female; mean age, 69.5 years) with MCI completed the study. Following the 6-month intervention, they exhibited a significant increase in the MoCA total score over time [F(2.32) =10.59, p < 0.0001]. Additionally, the deoxygenated hemoglobin beta coefficient in the left frontopolar prefrontal cortex significantly decreased during the Stroop task after the intervention. The Dementia Prevention & Care Program, which integrates herbal medicine and acupuncture, may enhance cognitive function in individuals with MCI. Moreover, the observed changes in prefrontal cortex activity after completion of the program suggest a need for further investigation of the underlying mechanisms.

Executive functions and theory of mind development in preschoolers: Insights from NIRS data

Numerous studies have highlighted the importance of executive functions (EFs) in the development of Theory of Mind (ToM) in preschoolers. However, research focusing on young children at the neural level has been limited. This study examined the relationship between EFs and ToM in twenty-nine healthy Japanese preschoolers aged 5–7 years, focusing on neural responses during EF and ToM tasks using near-infrared spectroscopy (NIRS) to monitor prefrontal cortex (PFC) activity. The study utilized EF tasks and the Sally-Anne scenario to assess false- and true-belief understanding, aiming to provide a comprehensive analysis of ToM capabilities. Results indicated that despite advanced EF capabilities and a ceiling effect across all EF tasks, there were no significant correlations between EF performance or verbal ability and ToM task performance. NIRS data revealed no PFC activation during the Stroop task. However, activation was observed in the left and right lateral PFC in the control false belief condition, the left lateral PFC in the false belief condition, and across all PFC regions in the true belief condition during ToM tasks. Significant relationships were found between behavioral performance in ToM tasks and neural activity in key brain regions. The study also identified a complex relationship between false and true belief reasoning, suggesting a nuanced developmental trajectory for ToM. These findings underscore the crucial role of early childhood in the development of ToM and the complex interplay between cognitive functions and neural efficiency in understanding others' mental states.

Comparative effects of cognitive and instability resistance training versus instability resistance training on balance and cognition in elderly women

This study investigates the effects of integrated instability resistance training and cognitive training (IRCT) versus isolated instability resistance training (IRT) on balance, gait, muscle strength, and cognitive functions in elderly women.This randomized controlled trial included 36 participants, with 18 in the IRCT group and 18 in the IRT group. The sample size was estimated to achieve a statistical power of 0.95 with a large effect size (0.40; n = 12 each group). The closed-eye single-leg stand test was measured for static balance, the closed-eye stepping test, and the Timed Up and Go Test (TUGT) were measured for dynamic balance. Dual-task balance was assessed by combining the TUGT with cognitive tasks (TUGT-C) and motor tasks (TUGT-M). Gait performance was evaluated using a gait function system. Lower limb muscle strength was measured with the 30-Second Chair Stand Test. Cognitive function was assessed through the Trail Making Test (TMT), Digit Span Test (DST), Stroop Color and Word Test (Stroop), and Digit Symbol Substitution Test (DSST). Results IRCT group showed better improvements in both cognitive (p < 0.001) and motor (p = 0.812 for baseline; p < 0.001 for post-intervention) dual-task abilities, IRCT also experienced better enhancement in certain cognitive functions, particularly in the TMT (p = 0.001) and DSST (p = 0.022) compared to the IRT group. Both groups demonstrated enhancements in walking abilities as shown on selective markers of the gait performance test (p < 0.05) and leg muscle strength via 30-Second Chair (p < 0.001 for time main effect). These results suggest that combining cognitive exercises with physical training more effectively addresses the complex challenges associated with aging in women. The study highlights the potential of comprehensive training approaches in boosting health and quality of life for the elderly, with implications for developing tailored exercise programs focused on reducing fall risks and enhancing quality of life in this population.

Humanizing neuropsychological assessment: The role of empathy

Context Recent research and the majority of neuropsychological testing manuals emphasize the importance of establishing a proper relationship between the evaluator and the evaluatee. However, there is relatively little empirical research on this point. Objectives The objective of this study was to operationalize empathy in the evaluator/evaluatee relationship during neuropsychological assessment. The subsequent aim was to determine the impact of this empathy on the evaluator/evaluatee relationship and cognitive performance. Methods The participants, designated as “evaluatees”, were randomly assigned to complete a brief neuropsychological test in either an empathic (N = 47) or neutral condition (N = 47). The neuropsychological tests included the Stroop task from the GREFEX battery, the Letter-Number Sequencing from the WAIS-IV, and the d2 test of attention. Following the tests, participants completed scales indicating perceived relationship with the evaluator, lived experience of the test, and sociodemographic information. Results The manipulation check indicated that it was possible to manipulate empathy. Evaluators demonstrating empathy led to a better evaluator/evaluatee relationship. However, the results regarding cognitive performance were less consistent. Conclusions In conclusion, there is a need for improvement in clinical neuropsychological practice with regard to relational competencies during testing. This study proposes benchmarks to make the evaluator’s empathy perceptible. This technique has not been shown to have a consistent effect on cognitive performance.

Directionality and Individual Differences in Consecutive Interpreting

This study aims to examine the students’ consecutive interpreting in English and Turkish. This study was carried out with 32 senior students who are native Turkish speakers at the Department of English Translation and Interpreting. The students were required to render the speeches chosen from the EU Speech Repository, a speech bank for interpreting studies, in the En-Tr and Tr-En directions, respectively. The students were audio-recorded. In addition, students’ working memory (WM) capacities were determined by conducting digit span and word span tests, and attention levels were determined by conducting monolingual and bilingual Stroop test. The data was assessed with the overall assessment score of consecutive interpreting performance, total duration, pauses, linguistic errors, participants’ individual differences (WM and attention level), and directionality. The recordings were transcribed and assessed by two experts. A detailed error analysis was performed using MAXQDA Analytics Pro Academic. Students with higher WM levels also have better performance in the En-Tr direction, yet this is not observed in the Tr-En. This can be explained by the fact that students have more difficulty and spend more time interpreting to L2 due to their language proficiency in translation (such as lack of vocabulary, difficulties related to structure, etc.). There was no significant relationship between students' attention skills and interpreting performance. Differences were also observed in the errors and strategies used by students depending on directionality. It is expected that this study will contribute to understanding the consecutive interpreting process, revealing the main difficulties, and thereby contributing to interpreter training.

Effects of menstrual cycle on cognitive function, cortisol, and metabolism after a single session of aerobic exercise

Aim This study aimed to investigate the effects of the two pre-ovulatory and mid-luteal phases of the menstrual cycle on cognitive function, as well as possible mediators of metabolism and salivary cortisol, at rest and after an aerobic exercise session. Study design Twelve active young unmarried women aged 22–30 years volunteered to participate in the study. The participants performed a 20-min exercise session on a cycle ergometer at 60–70% of their reserve heart rate twice, during the follicular (pre-ovulation: days 7–10) and luteal (mid-luteal: days 21–24) phases of the menstrual cycle. Saliva samples were collected to measure cortisol. Fat utilization, respiratory exchange ratio (RER), and energy expenditure (during exercise) were measured using a spiroergometer. Cognitive function was assessed using the Stroop test. Cognitive function and cortisol levels were measured before and after each exercise session. Results The findings of this study indicated no significant differences in variables during the resting follicular and luteal phases. Cortisol levels and cognitive function were increased after exercise compared with before exercise in both the follicular and luteal phases. Cortisol and fat utilization after exercise were significantly higher in the follicular phase than in the luteal phase. There were no significant differences between the follicular and luteal phasesregarding the effects of exercise on cognitive function, energy expenditure, and RER. Conclusion In general, the follicular and luteal phases of menstruation may not affect cognitive function in response to a single aerobic exercise session, although they change some metabolic factors and cortisol.

Acquiescing to intuition in individuals prone to delusions: alterations in dual processes and cognitive control

Anomalous beliefs exist on a continuum ranging from conventional beliefs to delusions. Recent work proposes that delusions may be formed via acquiescence, in which intuitive beliefs arise and persist despite awareness that they conflict with rationality. Cognitive control theory can similarly explain how we fail to detect that delusional beliefs conflict with rationality, and/or marshal cognitive control (analytic) resources to override them. We measured intuitive processes using a decision-making task and analytic processes using Stroop and cognitive reflection (CRT) tasks. Stronger intuition and lower CRT/Stroop scores were associated with acquiescence. Importantly, those less prone to delusions were more likely to override their intuition as their analytic strength increased; however, for more delusion-prone participants, analytic strength predicted an increased likelihood of acquiescence. Findings highlight an interactive role of intuitive and analytic processes in anomalous beliefs, including delusions, such that cognitive resources may be rallied to rationalize intuitions.

Dissecting neural correlates of theory of mind and executive functions in behavioral variant frontotemporal dementia

Behavioral variant frontotemporal dementia (bvFTD) is characterized by profound and early deficits in social cognition (SC) and executive functions (EF). To date it remains unclear whether deficits of the respective cognitive domains are based on the degeneration of distinct brain regions. In 103 patients with a diagnosis of bvFTD (possible/probable/definite: N = 40/58/5) from the frontotemporal lobar degeneration (FTLD) consortium Germany cohort (age 62.5±9.4 years, gender 38 female/65 male) we applied multimodal structural imaging, i.e. voxel-based morphometry, cortical thickness (CTH) and networks of structural covariance via source based morphometry. We cross-sectionally investigated associations with performance in a modified Reading the Mind in the Eyes Test (RMET; reflective of theory of mind - ToM) and five different tests reflective of EF (i.e. Hamasch-Five-Point Test, semantic and phonemic Fluency, Trail Making Test, Stroop interference). Finally, we investigated the conjunction of RMET correlates with functional networks commonly associated with SC respectively ToM and EF as extracted meta-analytically within the Neurosynth database. RMET performance was mainly associated with gray matter volume (GMV) and CTH within temporal and insular cortical regions and less within the prefrontal cortex (PFC), whereas EF performance was mainly associated with prefrontal regions (GMV and CTH). Overlap of RMET and EF associations was primarily located within the insula, adjacent subcortical structures (i.e. putamen) and the dorsolateral PFC (dlPFC). These patterns were more pronounced after adjustment for the respective other cognitive domain. Corroborative results were obtained in analyses of structural covariance networks. Overlap of RMET with meta-analytically extracted functional networks commonly associated with SC, ToM and EF was again primarily located within the temporal and insular region and the dlPFC. In addition, on a meta-analytical level, strong associations were found for temporal cortical RMET correlates with SC and ToM in particular. These data indicate a temporo-frontal dissociation of bvFTD related disturbances of ToM and EF, with atrophy of the anterior temporal lobe being critically involved in ToM deficits. The consistent overlap within the insular cortex may be attributable to the multimodal and integrative role of this region in socioemotional and cognitive processing.

A Comparative Analysis of Neurocognitive Function in Community- and Hospital-Based Patients With Schizophrenia.

The study compared differences in various neurocognitive characteristics across treatment modalities among schizophrenia patients recruited in one city between July 2020 and June 2023 who were on regular medication. Of the 151 participants, 113 were included in the analysis. Participants were divided into community-based and hospital-based groups, and their demographics and clinical characteristics, including insight, quality of life, positive and negative symptoms, and personal and social functioning, were examined. In addition, several aspects of cognition were assessed using neurocognitive assessments such as the Trail Making Test (TMT), Stroop test, and Wisconsin Card Sorting Test (WCST). After adjusting for age differences between groups, the final analysis included data from 42 participants in the community-based group and 33 participants in the hospital-based group. Hospital-based group participants completed Stroop-W more rapidly, excelled in Rey-Osterrieth Complex Figure Test recall and recognition, and incurred fewer TMT Part B (TMT-B) and Stroop-C errors. Additionally, they outperformed in WCST total, non-persistent errors, and categories completed. Contrastingly, community-based group participants showed superior outcomes in WCST persistent responses and errors, suggesting specific neurocognitive strengths. We found differences in neurocognitive characteristics between the two groups. These differences were consistent across a range of cognitive domains, including attention, visual discrimination, memory, and executive functioning. Further large-scale study is needed to generalize cognitive characteristics across treatment modalities.

A comment on the Revised Diffusion Model for Conflict tasks (RDMC).

In conflict tasks, such as the Simon, Eriksen flanker, or Stroop task, a relevant and an irrelevant feature indicate the same or different responses in congruent and incongruent trials, respectively. The congruency effect refers to faster and less error-prone responses in congruent relative to incongruent trials. Distributional analyses reveal that the congruency effect in the Simon task becomes smaller with increasing RTs, reflected by a negative-going delta function. In contrast, for other tasks, the delta function is typically positive-going, meaning that congruency effects become larger with increasing RTs. The Diffusion Model for Conflict tasks (DMC; Ulrich et al., Cognitive Psychology, 78, 148-174, 2015) accounts for this by explicitly modeling the information accumulated from the relevant and the irrelevant features and attributes negatively- versus positively-sloped delta functions to different peak times of a pulse-like activation resulting from the task-irrelevant feature. Because the underlying function implies negative drift rates, Lee and Sewell (Psychonomic Bulletin & Review, 31(5), 1-31, 2024) recently questioned this assumption and suggested their Revised Diffusion Model for Conflict tasks (RDMC). We address three issues regarding RDMC compared to DMC: (1) The pulse-like function is not as implausible as Lee and Sewell suggest. (2) RDMC itself comes with a questionable assumption that different parameters are required for congruent and incongruent trials. (3) Moreover, we present data from a new parameter recovery study, suggesting that RDMC lacks acceptable recovery of several parameters (in particular compared to DMC). In this light, we discuss RDMC as not (yet) a revised version of DMC.

Increased 1H-NMR metabolomics-based health score associates with declined cognitive performance and functional independence in older adults at risk of cardiovascular disease.

The 1-HMR metabolomics-based MetaboHealth score, comprised of 14 serum metabolic markers, associates with disease-specific mortality, but it is unclear whether the score also reflects cognitive changes and functional impairment. We aimed to assess the associations between the MetaboHealth score with cognitive function and functional decline in older adults at increased cardiovascular risk. A total of 5292 older adults free of dementia at baseline with mean age 75.3years (SD = 3.4) from the Prospective Study of Pravastatin in the Elderly (PROSPER). MetaboHealth score were measured at baseline, and cognitive function and functional independence were measured at baseline and every 3months during up to 2.5years follow-up. Cognitive function was assessed using the Stroop test (selective attention), the Letter Digit Coding test (LDCT) (processing speed), and the two versions of the Picture Learning test (delayed and immediate; memory). Two tests of functional independence were used: Barthel Index (BI) and instrumental activities at daily living (IADL). A higher MetaboHealth score was associated with worse cognitive function (in all domains) and with worse functional independence. For example, after full adjustments, a 1-SD higher MetaboHealth score was associated with 9.02s (95%CI 7.29, 10.75) slower performance on the Stroop test and 2.79 (2.21, 3.26) less digits coded on the LDCT. During follow-up, 1-SD higher MetaboHealth score was associated with an additional decline of 0.53s (0.23, 0.83) on the Stroop test and - 0.08 (- 0.11, - 0.06) points on the IADL. Metabolic disturbance, as reflected by an increased metabolomics-based health score, may mark future cognitive and functional decline.

Proactive control for conflict resolution is intact in subclinical obsessive-compulsive individuals.

BackgroundObsessive-compulsive (OC) traits (i.e., tendency to implement stereotyped behaviors to avoid negative consequences) are transversally observed in psychiatric disorders largely differing in terms of clinical manifestations and etiopathogenesis. Interestingly, OC traits were also extensively found in the prodromal phases of the full-blown psychopathology and in healthy relatives of affected individuals. Moreover, OC traits were found to be associated—and possibly underlain by—cognitive control impairments. Nonetheless, the role of such interplay in the onset of OC disorders is yet to be understood. We hypothesized that OC traits are associated with abnormalities in proactively implement cognitive control for solving conflict.MethodsWe administered healthy individuals (n = 104) with the perifoveal spatial Stroop task to measure their ability of solving conflict in a proactive fashion, and with Obsessive-Compulsive Inventory (OCI) to stratify population according to the severity of OC traits.ResultsAnalysis of response times by means of Linear Mixed-effect models revealed that proactive control performance was not associated with and the severity of OC traits. Furthermore, an equivalence test (Two One-Sided Test) revealed that the association between OCI scores and task performance was equivalent to zero.ConclusionThese results suggest that the interplay between OC traits and proactive control abnormalities might not contribute to the development of OC-related disorders. Therefore, the role of other cognitive endophenotypes should be scrutinized for exploiting alternative prevention and intervention strategies.

Assessing acute effects of two motor-cognitive training modalities on cognitive functions, postural control, and gait stability in older adults: a randomized crossover study.

The process of aging often accompanies a decline in cognitive function, postural control, and gait stability, consequently increasing the susceptibility to falls among older individuals. In response to these challenges, motor-cognitive training has emerged as a potential intervention to mitigate age-related declines. This study aims to assess the acute effects of two distinct motor-cognitive training modalities, treadmill dual-task training (TMDT) and interactive motor-cognitive training (IMCT), on cognitive function, postural control, walking ability, and dual-task performance in the elderly population. In this randomized crossover study, 35 healthy elderly individuals (aged 60-75) participated in three acute training sessions involving TMDT, IMCT, and a control reading condition. Assessments of executive function, postural control, gait performance, and cognitive accuracy were conducted both before and after each session. Both TMDT and IMCT improved executive functions. Notably, IMCT resulted in a significant enhancement in correct response rates and a reduction in reaction times in the Stroop task (p < 0.05) compared to TMDT and the control condition. IMCT also led to an increase in dual-task gait speed (p < 0.001) and showed a trend towards improved cognitive accuracy (p = 0.07). Conversely, TMDT increased postural sway with eyes open (p = 0.013), indicating a potential detriment to postural control. The findings suggest that IMCT holds greater immediate efficacy in enhancing cognitive function and gait stability among older adults compared to TMDT, with a lesser adverse impact on postural control. This underscores the potential of IMCT as a preferred approach for mitigating fall risk and enhancing both cognitive and physical functions in the elderly population.

Clinical features of vascular cognitive impairment

Vascular cognitive impairment (VCI) can occur in cerebrovascular disease of varying degree of severity, which requires further investigation.Objective: to identify specific features of attention deficit and executive function (EF) impairment in VCI and to determine the relationship between cognitive, neurological and radiological signs of the disease.Material and methods. The study involved 80 patients (51 with VCI – the main group and 29 healthy volunteers – the control group). All participants underwent clinical and neuropsychological examination and MRI of the brain. VCI was diagnosed according to 2014 VASCOG criteria. The neuropsychological examination included an assessment of the general cognitive function (MoCA test, MMSE); general EF (FAB, EXIT-25); episodic memory (12-word memory test and Benton Visual Retention Test); semantic memory (categorical association method); initiation and productivity of cognitive activity (literal associations); attention [TMT-A, Symbol-Digit Modalities Test (SDMT)]; cognitive flexibility (TMT-B); cognitive control (Stroop test).Results. As a result of the study, three subgroups of patients with VCI were identified: 1) predominantly attention deficit (AD); 2) AD and significant decrease in cognitive flexibility (CFD); 3) AD in combination with a significant cognitive control deficiency (CCD). The TMT-A and SDMT tests were significantly worse in all subgroups of VCI compared to the control group, with the worst SDMT score in subgroup 2. Subgroup 2 also had the longest time to complete the TMT-B test. Subgroup 3 was characterized by the worst Stroop test results, and uncontrolled arterial hypertension was more common in this group. Gait disturbances were significantly more frequent in subgroup 2, and increased reflexes of oral automatism and grasp reflex were observed in subgroup 3. White matter hyperintensity (WMH) was more pronounced in subgroup 2, and lacunar infarcts (LI) were more frequent in subgroup 3. Prevalence of LI and severity of WMH were lowest in subgroup 1.Conclusion. The main features of VCI are attention deficit and EF impairment, characteristics of EF disorders depend on the severity and type of vascular lesions of the brain. Progression of WMH is associated with more pronounced CFD and an increase in the number of LI is associated with CCD. There is a correlation between CFD and gait disturbances and between CCD and lack of primitive reflexes inhibition.

Large-scale structural covariance networks changes relate to executive function deficit in betel quid-dependent chewers.

Previous studies demonstrate deficits in executive function for betel quid-dependent (BQD) patients. Large-scale structural covariance network (SCN) based on gray matter (GM) morphometry may be able to explore the neural mechanism of executive dysfunction in BQD individuals. This study aims to identify spatial covariance patterns of GM volume and to investigate their association with executive dysfunction in BQD individuals. Sixty-four BQD individuals and 48 sex- and age-matched healthy controls (HCs) underwent T1-weighted structural MRI examination and executive function assessments, including the Backward Digit Span (BDS) test and Stroop Color and Word (SCW) test. Seventy SCNs based on GM volume covariance patterns were defined using independent component analysis. An SCN-based classifier was constructed to differentiate between BQD and HC individuals. Receiver operating characteristic (ROC) curves were applied to evaluate the performance of the SCN-based classifier. Linear regression analyses were performed to investigate the association between SCN network indices and executive function indices. Six SCNs had higher classifications for differentiating between BQD and HC individuals. The area under the ROC curve of the SCN-based classifier was 0.812 in the training set and 0.771 in the testing set. Furthermore, linear regression analyses demonstrated that the network indices in the thalamus were associated with BDS scores adjusted for age, sex, and education. Large-scale SCNs could provide potential imaging markers for differentiating BQD and HC groups. The loss of network index in the thalamus was associated with working memory, indicating that SCNs could reveal executive dysfunction in BQD individuals.

The DLPFC is centrally involved in resolving Stroop conflicts, suppressing distracting sensory input within the auditory and visual system.

Cognitive control is a prerequisite for successful, goal-oriented behavior. The dorsolateral prefrontal cortex (DLPFC) is assumed to be a key player in applying cognitive control; however, the neural mechanisms by which this process is accomplished are still unclear. To further address this question, an audiovisual Stroop task was used, comprising simultaneously presented pictures and spoken names of actors and politicians. Depending on the task block, participants had to indicate whether they saw the face or heard the name of a politician or an actor (visual vs. auditory blocks). In congruent trials, both stimuli (visual and auditory) belonged to the same response category (actor or politician); in incongruent trials, they belonged to different categories. During this task, activity in sensory target regions was measured via functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG), respectively. Specifically, fNIRS was used to monitor activity levels within the auditory cortex, while the EEG-based event-related potential of the N170 was considered as a marker of FFA (fusiform face area) involvement. Additionally, we assessed the effects of inhibitory theta-burst stimulation-a specific protocol based on repetitive transcranial magnetic stimulation (rTMS)-over the right DLPFC. Non-invasive brain stimulation is one of the few means to draw causal conclusions in human neuroscience. In this case, rTMS was used to temporarily inhibit the right DLPFC as a presumed key player in solving Stroop conflicts in one of two measurement sessions; then, effects were examined on behavioral measures as well as neurophysiological signals reflecting task-related activity in the frontal lobes and sensory cortices. The results indicate a central role of the DLPFC in the implementation of cognitive control in terms of a suppression of distracting sensory input in both the auditory cortex and visual system (FFA) in high-conflict situations. Behavioral data confirm a reduced Stroop effect following previous incongruent trials ("Gratton effect") that was only accomplished with an intact DLPFC (i.e., following placebo stimulation). Because non-invasive brain stimulation is uniquely suited to causally test neuroscientific hypotheses in humans, these data give important insights into some of the mechanisms by which the DLPFC establishes conflict resolution across different sensory modalities.

Current oral contraceptive use affects explicit and implicit measures of depression in women.

Some data suggest that increased depressive symptoms may occur in women using combined oral contraceptives (OCs). However, this idea is controversial and the existing evidence is conflicting. The present study compared negative affect in 53 healthy women (M age = 19.9 years) during intervals of active daily OC hormone intake and during the washout week of the contraceptive cycle when no exogenous estrogens or progestins are used. A prospective counterbalanced repeated-measures study design was employed. Depressive affect was evaluated using standard psychometric tests of explicit (self-perceived) and implicit negative affect. Implicit measures are considered less subject to bias related to social expectations, self-awareness, or willingness to disclose. Other than their usual OCs, participants were medication-free and had been using OCs for a median of 12 mo. We found that measures of implicit affect (e.g., Affect Misattribution Procedure, Emotional Stroop Test) displayed a more depressive-like pattern of performance during active hormone intake, particularly among a subgroup of OC users who reported experiencing high levels of depressive affect more generally. In contrast, participants' self-perceptions suggested that they perceived their negative symptoms to be greater during the 'off' phase of the OC cycle, when OC steroids are withdrawn and menses occurs. The present findings reinforce the possibility of depressive mood effects associated with OC usage, and highlight the utility of including implicit measures, but also illustrate the complexity of mood assessment in OC users.

Acute Ketone Monoester Supplementation in Young Adults: Modulating Metabolic and Neurocognitive Functions Across Body Weights.

This study investigated the acute effects of ketone monoester on metabolic and neurocognitive indicators and underlying metabolism-brain-cognition interactions among young adults of healthy weight (HW) and those with overweight/obesity (OW). Forty participants were divided into two groups: HW (n = 20, age 23.80±3.96 years, body mass index [BMI] 21.49±1.80 kg/m²) and OW (n = 20, age 22.00±2.13 years, BMI 28.23±3.48 kg/m²). Each participant completed two trials (ketone monoester vs. placebo, 395 mg/kg dose) in a randomized order. Metabolic indicators (blood beta-hydroxybutyrate [BHB] and glucose) and neurocognitive function (causal density via functional near-infrared spectroscopy and cognitive interference via the Stroop task) were measured at baseline, 30 minutes, and 90 minutes post-supplementation. A chain mediation model was constructed to test the indirect effects of BHB level on cognitive interference through mediators like blood glucose and causal density. In the linear mixed models, significant effects were observed for trial (β = -0.92, 0.20, -0.04, 25.53) and assessment time (β = 0.50, -0.14, 0.09, -62.88) in BHB, glucose, causal density, and cognitive interference (p < 0.05), but not for group factors. Compared to OW, the effects of ketone monoester on prefrontal connectomes were more enduring in the HW (p < 0.05). Elevated BHB level improved cognitive function through decreasing glucose level and increasing causal density, with estimate of -0.63. Acute ketone monoester supplementation elevated levels of blood BHB and prefrontal connectomes and decreased levels of glucose and cognitive interference, regardless of weight status. Elevated blood BHB enhanced cognitive function through multi-tiered neurometabolic pathways.