Stroop Task Research Articles

Benefits of postural sway to succeed in goal-directed visual tasks

When individuals stand, they sway and so have to maintain their balance. It is generally expected that task performance is worse when standing and swaying than when sitting and therefore not swaying. In contrast, we hypothesized that greater sway is associated with better task performance in the absence of external perturbations of posture. Twenty-four healthy, young adults performed two goal-directed, modified Stroop tasks (incongruent and reversed incongruent) in four body position conditions (standing against a vertical surface, and standing freely with a wide, standard or narrow stance). Centre of pressure (COP) sway, head sway, eye movements, visual attention, and task performance were recorded. Partial correlation analyses showed significant positive associations between task performance and some COP and head sway variables, after controlling for the level of visual attention. Analyses of variance with three factors (body position, task difficulty, target distance) also showed significant interaction effects between body position (and therefore postural sway) and the number of accurate target findings. The presence of these interactions showed that narrow stance was both the best body position for performing the incongruent task and the worst body position for performing the reversed incongruent task. Overall, COP sway and head sway can increase task performance. Hence, healthy, young adults in quiet stance appear to use sway to explore their environment more effectively. However, it should be borne in mind that our hypothesis was formulated solely with regard to healthy, young adults standing in quiet stance.

Verbal memory is linked to average oxygen saturation during sleep, not the apnea-hypopnea index nor novel hypoxic load variables

IntroductionThe apnea-hypopnea index (AHI) is the current diagnostic parameter for diagnosing and estimating the severity of obstructive sleep apnea (OSA). It is, however, poorly associated with the main clinical symptom of OSA, excessive daytime sleepiness, and with the often-seen cognitive decline among OSA patients. To better evaluate OSA severity, novel hypoxic load parameters have been introduced that consider the duration and depth of oxygen saturation drops associated with apneas or hypopneas. The aim of this paper was to compare novel hypoxic load parameters and traditional OSA parameters to verbal memory and executive function in OSA patients. MethodA total of 207 adults completed a one-night polysomnography at sleep laboratory and two neuropsychological assessments, the Rey Auditory Verbal Learning Test and Stroop test. Results: Simple linear regression analyses were used to evaluate independent associations between each OSA parameter and cognitive performance. Associations were found between immediate recall and arousal index, hypoxia <90 %, average SpO2 during sleep, and DesSev100+RevSev100. Total recall was associated with all OSA parameters, and no associations were found with the Stroop test. Subsequently, sex, age, and education were included as covariates in multiple linear regression analyses for each OSA parameter and cognitive performance. The main findings of the study were that average SpO2 during sleep was a significant predictor of total recall (p < .007, β = −.188) with the regression model explaining 21.2 % of performance variation. Average SpO2 during sleep was also a significant predictor of immediate recall (p < .022, β = −.171) with the regression model explaining 11.4 % of performance variation. Neither traditional OSA parameters nor novel hypoxic load parameters predicted cognitive performance after adjustment for sex, age, and education. ConclusionThe findings validate that the AHI is not an effective indicator of cognitive performance in OSA and suggest that average oxygen saturation during sleep may be the strongest PSG predictor of cognitive decline seen in OSA. The results also underline the importance of considering age when choosing neurocognitive tests, the importance of including more than one test for each cognitive domain as most tests are not pure measures of a single cognitive factor, and the importance of including tests that cover all cognitive domains as OSA is likely to have diffuse cognitive effects.

From the latin "re-cordis, passing through the heart": autonomic modulation differentiates migraineurs from controls when recounting a significant life event.

The literature on clinical psychophysiology highlights the possibility of using Heart Rate Variability (HRV) as an index of psychophysical balance and resilience to stress. This study investigates the differences in stress reactivity and subsequent recovery between a group of migraineurs and healthy controls. Socio-demographic (i.e., sex, age, profession, marital status, and level of education) and psychophysiological (HR and HRV) measures of a group of thirty subjects with migraine (26 migraineurs without aura (86.7%), 2 migraineurs with aura (6.7%), and 2 migraineurs with and without aura (6.7%)) and from thirty healthy control subjects were collected. In particular, HRV was analyzed through frequency-domain parameters, including Low-Frequency (LF; 0.04-0.15 Hz) and High-Frequency (HF; 0.15-0.4 Hz) bands as well as LF/HF ratio during a Psychophysiological Stress Profile (PSP) structured in seven phases: (1) Baseline, (2) Objective stressor 1 (Stroop Test), (3) Rest 1, (4) Objective stressor 2 (Mental Arithmetic Task), (5) Rest 2, (6) Subjective stressor (recount a significant life event), and (7) Rest 3. The LF, HF, and LF/HF ratio values were transformed into a logarithmic scale (i.e., log-LF, log-HF, and log LF/HF ratio). Additionally, LF and HF were converted into normalized units (0-100) (i.e., LF% and HF%) which, in turn, were used to obtain reactivity and recovery to stress through delta values (Δ) calculation. Subjects with migraine reported greater ΔLF% levels of reactivity and recovery to subjective stressor, demonstrating a prevalence of sympathetic activity while recounting a personal life event. At the same time, a lowering of the same values was found in the subjects of the group control. Our results underline the importance of conducting a psychophysiological assessment in patients with headaches because reduced stress management skills could influence the clinical manifestations of the disease, considering stress as one of the most common triggers for migraine patients.

Acute effects of breaking up sitting time with isometric exercise on cognition in healthy adults

The aim of this study was to analyze the acute effects of different sitting break strategies on cognition in healthy adults. Twelve physically inactive adults (8 women, 28 ± 9 years; 25.10 ± 4.90 kg/m²) randomly completed three 3 hour conditions: 2-min isometric leg extension exercise sitting breaks at 30% of maximal voluntary contraction every 30-min; 2-min light-intensity walking sitting breaks every 30-min; sitting without breaks. Stroop and Eriksen Flanker tests were used to measure cognition before and after conditions. Generalized estimated equations were used to analyze cognition responses. Data are presented as mean ± standard deviation. Stroop congruent phase decreased for all conditions (Isometric: 1.56 ± 0.20s Pre vs 1.49 ± 0.12s Post; Walking: 1.67 ± 0.22s Pre vs 1.54 ± 0.19s Post; Control: 1.69 ± 0.24s Pre vs 1.59 ± 0.26s Post; p = 0.044). There were no significant effects on Stroop incongruent phase, Stroop effect, or Eriksen-Flanker (p &gt; 0.05 for all). In conclusion, walking or isometric exercise sitting breaks do not acutely improve cognition in healthy adults.

High Cognitive Effort Prior to Velocity-Based Training Sessions Reduces Rate of Force Development but Not Maximum Strength Gains in Untrained Male Adults.

This study aimed to analyze the chronic effect of high cognitive effort immediately before resistance exercise sessions on neuromuscular performance in untrained male adults. We used a mixed experimental design, with the group as between-participants factor and time as within-participants factor. Thirty-four participants were randomly assigned to two parallel groups: high cognitive effort (n = 17) and control (n = 17). Subjects in the control group were seated for 30 min before the resistance exercise sessions, while the high cognitive effort group completed incongruent trials of the Stroop task until subjective mental fatigue was present immediately before resistance exercise sessions. Participants attended 45 sessions over 15 weeks, consisting of three familiarizations, three baseline evaluations, 36 velocity-based training sessions, and three postexperiment evaluation sessions. Rate of force development (RFD) during the isometric mid-thigh pull, half back-squat 1-RM, and countermovement jump (CMJ) were measured before and after the 12-week intervention. A significant group × time interaction effect was found for the average RFD at 0-250 ms (p < 0.05), with greater improvements for the control group than for the high cognitive effort group. There was no group × time interaction for half back-squat 1-RM (p > 0.05). Also, there was no group × time interaction for CMJ (p > 0.05). In conclusion, repeated high cognitive effort immediately prior to resistance exercise sessions is a phenomenon that can induce greater early velocity loss and, consequently, impairs the improvements in RFD. However, this did not inhibit the increased performance for explosive strength and CMJ in male untrained adults. High cognitive effort before resistance exercise sessions should be avoided.

Does selective attention demand affect the physiological complexity of postural control in faller community-dwelling older adults?

Background: The physiological complexity of postural control during selective attention demand can be used as an innovative method to identify faller community-dwelling older. Objective: To analyze the effect of selective attention on the complexity of postural control in faller community-dwelling older adults. Methods: A total of 57 older adults (60 to 80 years) were divided between the faller group (Fallers n = 21) and the non-faller group (Non-fallers n = 36). An inertial sensor (Physilog® 5, GaitUp, Switzerland) was positioned over the second sacral vertebra to collect the participant’s body sway in the anteroposterior (AP) and mediolateral (ML) directions during the monochromatic and color Stroop test versions. The postural control’s complexity was calculated using MATLAB codes, employing the refined composite multiscale fuzzy entropy method. Statistical Package for Social Sciences was used to analyze the effects of interaction, group, and condition effects using linear mixed models with an alpha of 5%. Results: No significant interaction effects were observed in the AP (F = 0.18; p = 0.66) and ML (F = 0.00; p = 0.99) directions. No group effect was observed in the AP (F = 1.23; p = 0.26) and ML (F = 1.76; p = 0.18) directions. No condition effect was found in the AP (F = 0.06; p = 0.80) and ML (F = 3.54; p = 0.06) directions. Conclusion: Once-only faller community-dwelling older adults did not evidence worse physiological complexity than the non-fallers during selective attention demand in the upright standing posture.

Recognition of Emotional Prosody in Mandarin-Speaking Children: Effects of Age, Noise, and Working Memory.

Age, babble noise, and working memory have been found to affect the recognition of emotional prosody based on non-tonal languages, yet little is known about how exactly they influence tone-language-speaking children's recognition of emotional prosody. In virtue of the tectonic theory of Stroop effects and the Ease of Language Understanding (ELU) model, this study aimed to explore the effects of age, babble noise, and working memory on Mandarin-speaking children's understanding of emotional prosody. Sixty Mandarin-speaking children aged three to eight years and 20 Mandarin-speaking adults participated in this study. They were asked to recognize the happy or sad prosody of short sentences with different semantics (negative, neutral, or positive) produced by a male speaker. The results revealed that the prosody-semantics congruity played a bigger role in children than in adults for accurate recognition of emotional prosody in quiet, but a less important role in children compared with adults in noise. Furthermore, concerning the recognition accuracy of emotional prosody, the effect of working memory on children was trivial despite the listening conditions. But for adults, it was very prominent in babble noise. The findings partially supported the tectonic theory of Stroop effects which highlights the perceptual enhancement generated by cross-channel congruity, and the ELU model which underlines the importance of working memory in speech processing in noise. These results suggested that the development of emotional prosody recognition is a complex process influenced by the interplay among age, background noise, and working memory.

Can volumetric magnetic resonance imaging evaluations be helpful in the follow-up of cognitive functions in cognitively normal Parkinson's disease patients?

In this study, besides the evaluation of gray and white matter changes in cognitively normal Parkinson's disease (PD-CN) patients with volumetric magnetic resonance imaging (MRI) parameters, it was tried to show that some neuropsychological tests may be impaired in PD-CN patients. Twenty-six PD-CN patients and 26 healthy elderly (HC) participants were included in the current study. Global cognitive status was assessed using the mini-mental state examination (MMSE), and the Montreal cognitive assessment scale (MoCA). Attention and executive functions were evaluated using the Wechsler memory scale-revised (WMS-R) digit span test and trail making test (TMT) part A and part B, the Stroop test, semantic and phonemic fluency tests, and clock drawing test. Magnetic resonance imaging (MRI) was acquired according to the Alzheimer's disease neuroimaging initiative (ADNI) protocol. There were no significant differences among groups regarding age, sex, handedness, and years of education. In the comparison of the PD-CN group and the HC group, there was a statistical decrease in the total animal scores, lexical fluency, TMT part A and TMT part B scores in the PD-CN group. Subcortical gray matter volumes (GMV) were significantly lower in PD-CN patients. The PD-CN group had a significantly reduced total volume of right putamen and left angular gyrus compared to that in the HC group. We observed that putamen and angular gyrus volumes were lower in PD-CN patients. On the other hand, TMT part B may be a useful pretest in detecting the conversion of mild cognitive impairment in PD. Significant MRI volumetric measurements and neuropsychological test batteries can be helpful in the clinical follow-up in PD-CN patients.

Language and executive functions in patients with transcortical motor aphasia and Broca’s aphasia

ABSTRACT This study investigated language and executive functions (EF) in people with transcortical motor aphasia (TMA) and Broca’s aphasia (BA). Participants included 19 patients with TMA, 19 patients with BA, and 25 healthy controls. Verbal Fluency tests, Stroop tests and Trail-Making tests were administered to all participants, and the Boston Diagnostic Aphasia Examination (BDAE) was administered to participants with aphasia. Results showed that (1) both groups of patients with aphasia had poorer performance on Verbal Fluency tests, Stroop tests and Trail-Making tests than healthy controls; (2) participants with BA had superior performance on Stroop tests and Trail-Making tests, but not on Verbal Fluency tests, than participants with TMA, and (2) the performance on Verbal Fluency tests, Stroop tests and Trail-Making was significantly correlated with the performance on BDAE for participants with TMA, but not for participants with BA. These results suggest that EF deficits are present in both patients with TMA and those with BA. They also show that the relationship between EF deficits and language impairments in people with aphasia might depend on the type of aphasia, aspects of language, and the components of EF measured.

Control your emotions: evidence for a shared mechanism of cognitive and emotional control

ABSTRACT The current investigation examined the bidirectional effects of cognitive control and emotional control and the overlap between these two systems in regulating emotions. Based on recent neural and cognitive findings, we hypothesised that two control systems largely overlap as control recruited for one system (either emotional or cognitive) can be used by the other system. In two experiments, participants completed novel versions of either the Stroop task (Experiment 1) or the Flanker task (Experiment 2) in which the emotional and cognitive control systems were actively manipulated into either a high or low emotional-load condition (achieved by varying the proportions of negative-valence emotional cues) and a high and a low cognitive control condition (achieved through varying the proportion of conflict-laden trials). In both experiments, participants’ performance was impaired when both emotional and cognitive control were low, but significantly and similarly improved when one of the two control mechanisms were activated – the emotional or the cognitive. In Experiment 2, performance was further improved when both systems were activated. Our results give further support for a more integrative notion of control in which the two systems (emotional and cognitive control) not only influence each other, but rather extensively overlap.

Cognitive Fluency in L2: The Effect of Automatic and Controlled Lexical Processing on Speech Rate

The fluency of second language (L2) speech can be influenced by L2 proficiency, but also by differences in the efficiency of cognitive operations and personal speaking styles. The nature of cognitive fluency is still, however, little understood. Therefore, we studied the cognitive fluency of Finnish advanced students of English (N = 64) to understand how the efficiency of cognitive processing influences speech rate. Cognitive fluency was operationalised as automaticity of lexical access (measured by rapid word recognition) and attention control (measured by the Stroop task). The tasks were conducted in both L1 (Finnish) and L2 (English) to examine the (dis)similarity of processing in the two languages. Speech rate in a monologue task was used as the dependent measure of speaking performance. The results showed that after controlling for the L1 speech rate and L1 cognitive fluency, the L2 attention control measures explained a small amount of additional variance in L2 speech rate. These results are discussed in relation to the cognitive fluency framework and general speaking proficiency research.

Cognition in Patients with Spinocerebellar Ataxia 1 (SCA1) and 2 (SCA2): A Neurophysiological and Neuropsychological Approach.

Background/Objectives: Cognitive impairment in spinocerebellar ataxia patients has been reported since the early-disease stage. We aimed to assess cognitive differences in SCA1 and SCA2 patients. Methods: We performed neuropsychological (NPS) and neurophysiological (auditory event-related potentials, aERPs) assessments in 16 SCA1 and 18 SCA2 consecutive patients. Furthermore, clinical information (age at onset, disease duration, motor disability) was collected. Results: NPS tests yielded scores in the normal range in both groups but with lower scores in the Frontal Assessment Battery (p < 0.05) and Visual Analogue Test for Anosognosia for motor impairment (p < 0.05) in SCA1, and the Trail Making Test (p < 0.01), Raven's progressive matrices (p < 0.01), Stroop (p < 0.05), and emotion attribution tests (p < 0.05) in SCA2. aERPs showed lower N100 amplitude (p < 0.01) and prolonged N200 latency (p < 0.01) in SCA1 compared with SCA2. Clinically, SCA2 had more severe motor disability than SCA1 in the Assessment and Rating of Ataxia Scale. Conclusions: SCA2 showed more significant difficulties in attentional, visuospatial, and emotional function, and greater motor impairment. In contrast, SCA1 showed less cognitive flexibility/phasic ability, probably affected by a more severe degree of dysarthria. The same group revealed less neural activity during nonconscious attentional processing (N100-N200 data), suggesting greater involvement of sensory pathways in discriminating auditory stimuli. NFS did not correlate with NPS findings, implying an independent relationship. However, the specific role of the cerebellum and cerebellar symptoms in NPS test results deserves more focus.

Potential Impacts of Heartfulness Relaxation on Interpreting Performance: A Pilot Study

This mixed-methods pilot study investigates the effects of a brief seven-minute heartfulness relaxation intervention on interpreting students’ cognitive performance, perceived stress, and consecutive interpreting skills. Seven participants completed pre- and post-intervention measures, including the Stroop test, Perceived Stress Scale (PSS-10), and consecutive interpreting tasks. Qualitative data were collected through participant interviews and analyzed using thematic analysis. The quantitative results revealed significant improvements in executive function (p&lt;.001), perceived stress (p=.078), and Chinese to English and English to Chinese consecutive interpreting (p=.028) following the intervention. The qualitative findings indicated predominantly positive effects on interpreting performance, concentration, and focus, with mixed responses regarding relaxation, environmental factors, and effect sustainability. The convergence of the qualitative themes and quantitative improvements suggested that the heartfulness relaxation intervention enhanced the participants’ cognitive function, reduced fatigue, and optimized essential skills. These findings highlight the potential benefits of incorporating a brief relaxation practice into interpreter training and professional development. Limitations and future research directions are discussed, emphasizing the need for larger controlled trials to confirm the generalizability and long-term effects of the intervention. Overall, this pilot study provides a foundation for further investigations into the application of the brief heartfulness relaxation technique in the interpreting field.

Effects of electroacupuncture on cognitive symptoms in major depressive disorder: a pilot study and randomized controlled trial

Objectives To investigate the impact of electroacupuncture on cognitive function, quality of life (QoL), and depression severity in patients with major depressive disorder (MDD). Methods This double-blinded randomized controlled trial included 60 participants aged 18-55 with cognitive symptoms related to MDD at Thammasat University Hospital. Participants were divided into two groups: the electroacupuncture group combined with standard antidepressant treatment (EG; n=30) and the control group receiving standard care with placebo acupuncture (CG; n=30). The study assessed 1) executive functions using the Trail making test- B and Stroop Color and Word Test, 2) delayed recall, and 3) subjective cognitive complaint and Quality of life (QoL) using WHODAS 2.0. Depressive symptoms were measured using the Thai version of the Patient Health Questionnaire (PHQ-9). Baseline and post-intervention assessments were conducted over 10 weeks. Mann-Whitney U test analyzed treatment effects by comparing median differences between groups. Results Both groups exhibited similar demographics and cognitive traits. Cognitive improvement was observed in both groups at the endpoint. Intention-to-treat analysis revealed significantly higher median scores for subjective cognitive complaints in the EG compared to the CG (EG: Median = 5.5, CG: Median = 0.0, p=0.049). No serious side effects were identified from either electroacupuncture or placebo acupuncture. Conclusions Electroacupuncture improved subjective complaints in MDD patients with cognitive symptoms, but did not show effects on specific cognitive functions, QoL, or depressive symptoms. This study provides initial evidence supporting the potential of electroacupuncture in MDD patients with cognitive symptoms, suggesting opportunities for further research. Trial registration NCT06239740, February 2, 2024, ClinicalTrials.gov.

Frontal brain volume correlates of impaired executive function in schizophrenia

Cognitive impairments affect functional capacity in individuals with schizophrenia (SZH), but their neural basis remains unclear. The Wisconsin Card Sorting Test (WCST), and the Stroop Task (SCWT), are paradigmatic tests which have been used extensively for examining executive function in SZH. However, few studies have explored how deficits on these tasks link to brain volume differences commonly seen in SZH. Here, for the first time, we tested associations between FreeSurfer-derived frontal brain volumes and performance on both WCST and SCWT, in a well-matched sample of 57 SZH and 32 control subjects. We also explored whether these associations were dissociable from links to symptom severity in SZH. Results revealed correlations between volumes and task performance which were unique to SZH. In SZH only, volumes of right middle frontal regions correlated with both WCST and Stroop performance: correlation coefficients were significantly different to those present in the control group, highlighting their specificity to the patient group. In the Stroop task, superior frontal regions also showed associations with Stroop interference scores which were unique to SZH. These findings provide important detail around how deficits on these two paradigmatic executive function tasks link to brain structural differences in SZH. Results align with converging evidence suggesting that neuropathology within right middle frontal regions (BA9 and BA46) might be of particular import in SZH. No volumetric associations with symptom severity were found, supporting the notion that the structural abnormalities underpinning cognitive deficits in SZH differ from those associated with symptomatology.

Enhancing Ecological Validity: Virtual Reality Assessment of Executive Functioning in Children and Adolescents with ADHD.

SmartAction-VR uses virtual reality to simulate daily life tasks and assess cognitive performance based on the multi-errand paradigm. This study explored whether this new task could provide insights into the executive functioning of children and adolescents with ADHD in their everyday activities. A cross-sectional study was conducted between November 2021 and December 2022. It consisted of one session and was divided into two parts (cognitive tests; and SmartAction-VR). The sample comprised 76 children and adolescents with a median age (IQR) of 13 (11-14) years and an age range of 9-17 years. Of these participants, 60.50% (n = 46) were males. Out of this sample, 40 participants were in the ADHD group and 36 were in the neurotypical group. The following instruments were used: Waisman Activities of Daily Living Scale, Assessment of Sensory Processing and Executive Functioning, Pediatric Simulator Disease Questionnaire, Digit span subtest, Stroop test, NEPSY-II Subtest of Auditory Attention and Cognitive Flexibility, Trail Making Test, Zoo Map Test, and SmartAction-VR. The ADHD group demonstrated lower accuracy (U = 406, p = 0.010), higher values for total errors (U = 292, p = 0.001), more commissions (U = 417, p = 0.003), new actions (U = 470, p = 0.014), and forgetting actions (U = 406, p = 0.010), as well as fewer perseverations compared to the neurotypical group (U = 540.5, p = 0.029). Additionally, participants who forgot more actions were found to have lower independence in daily life (r = -0.281, p = 0.024). The correlations between the results of SmartAction-VR and activities of daily living, as well as cognitive tests, suggest that this new task could be useful for evaluating executive functioning in daily life.

Fall Risk, Postural Control, Muscle Strength and Cognitive Function in Patients with Liver Cirrhosis

Aim: Falls and fall-related injuries are common in liver cirrhosis. Studies mostly focus on minimal hepatic encephalopathy manifested by cognitive dysfunction as a predisposing factor for increased fall risk and postural instability in this population. Our aim was to investigate fall risk, postural control, muscle strength and cognitive function in patients with liver cirrhosis. Materials and Methods: Twenty-four patients and 24 healthy controls were enrolled in the study. Postural control was assessed using a posturographic system. Fall risk was assessed with Falls Efficacy Scale (FES) and Timed Up and Go Test (TUGT). Lower extremity muscle strength was assessed using a dynamometer. Cognitive function was evaluated with Stroop test. Results: Postural sway velocity (PSV) on foam surface eyes open (FSEO), FES score and TUGT duration were higher in patient group (p

Impact of carbon dioxide exposures on sleep latency among healthy volunteers: A randomized order, paired crossover study, evidence from the multiple sleep latency test

BackgroundDaytime sleepiness affects work efficiency, occupational safety, and public health. Although previous studies have reported an association between environmental carbon dioxide (eCO2) and daytime sleepiness, it has been challenging to draw a firm conclusion due to the lack of standardized sampling and profiling protocols. ObjectiveWe examined the effect of pure CO2 exposure at 5000 (ppm, parts per million) on daytime sleepiness. MethodsEleven healthy participants (males of 24 ± 3 years, mean ± SD) completed a four-nap multiple sleep latency test (MSLT) protocol in the environmentally controlled chamber under two conditions: the CO2 condition (4851 ± 229 ppm) and the Control condition (1102 ± 204 ppm). The subjective sleepiness level and cognitive performances were also evaluated using the Stanford Sleepiness Scale (SSS) questionnaire, Psychomotor Vigilance Test (PVT), and Stroop test after each nap session. ResultsA significant reduction in sleep latency was observed in the CO2 exposure condition (Control vs. CO2 = 13.1 ± 3.3 min vs. 9.7 ± 3.2 min). The subjective sleepiness scores were also significantly higher in the CO2 exposure condition than in the Control condition (Control vs. CO2 = 2.7 ± 0.5 vs. 4.7 ± 0.8). Cognitive responses after naps showed no significant difference across conditions. ConclusionThis study revealed that exposure to environmental CO2 at a concentration as high as the upper safety limit at work sites significantly shortened the sleep latency and enhanced subjective sleepiness during naps in the MSLT without affecting cognitive responses after each exposure. Our results demonstrated that exposure to high environmental CO2 induces daytime sleepiness that potentially compromises work efficiency and safety.

Relating distractor suppression to problematic drinking behavior

BackgroundImpaired cognitive control has been linked to weakened self-regulatory processes underlying compulsive substance intake. Previous research has provided evidence for impaired task performance in substance-abusing groups during Stroop and Go/No-Go tasks. Mechanisms of distractor suppression in visual search might also involve overlapping regulatory components that support goal-directed behavior by resolving the attentional competition between distractors and the target of search. However, the efficiency of learning-dependent distractor suppression has not been examined in the context of drug abuse and a direct comparison between cognitive control and distractor suppression is lacking. MethodA total of 84 participants were assigned either to the heavy drinking group (ALC, n = 42) or the control group (CTL, n = 42) based on self-reported substance use. Participants completed the Alcohol Use Disorders Identification Test (AUDIT) and Barratt Impulsiveness Scale (BIS). After that, participants completed a computerized version of the Stroop task, Go/No-go task, and a visual search task measuring learning-dependent distractor suppression. ResultsThe Stroop effect and the frequency of no-go errors did not differ between groups. However, learned distractor suppression was significantly blunted in the ALC group compared to the control group. Across participants, performance on the Stroop and Go/No-go task were correlated, while the magnitude of distractor suppression was related to neither. ConclusionsOur findings support a divergence of mechanistic processes underlying cognitive control and attentional control, and demonstrate impaired learning-dependent distractor suppression in heavy drinkers relative to a control group. Impaired distractor suppression offers new insight into why drug cues can be difficult to ignore.

Hair cortisol is a physiological indicator of training stress for female footballers.

Chronic physical stress in female athletes can reduce mental health and athletic performance. Therefore, a chronic physical stress assessment method is required. This study examined whether hair cortisol concentration (HCC) predicted chronic physical stress changes in female university football players. We took measurements in August and December, just before the Japan college national tournament. Self-reported training load was significantly positively correlated with HCC. Self-reported training load had no significant relationship with fatigue as measured by the Profile of Mood States 2nd Edition or with the stressors from the Stressor Scale for College Students. HCC was negatively correlated with reaction time in the spatial Stroop task, although the repeated correlation analysis showed no significant relationship. These results suggest that the chronic physical stress experienced by female footballers cannot be predicted by psychological indicators; however, they can be predicted by HCC, which could be used to prevent overtraining in these athletes.