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PubMed2026

The Acute Effects of Blood Flow Restriction on Ankle Muscle Reaction Time and Proprioception in Healthy Individuals.

Blood flow restriction (BFR) induces hypoxic and metabolic stress, which may alter afferent feedback and neuromuscular control. However, its acute effects on ankle sensorimotor function remain unclear. The aim of the study was to investigate the acute effects of lower-limb BFR on multidimensional ankle sensorimotor function in healthy adults. Twenty-four participants (12 females, 12 males) completed two conditions in randomized order and a crossover design: BFR at 60% arterial occlusion pressure (AOP) and a control condition (20 mmHg). All measurements were performed during occlusion. Outcomes included joint position sense (active and passive), kinesthesia, static and dynamic balance, lower-limb muscle activation (surface electromyography), and muscle reaction time during sudden ankle inversion. BFR impaired active joint position sense at 20 degrees of inversion (p = 0.011), with no changes at other angles or in kinesthesia. Static balance deteriorated, with increases in sway area (p = 0.017), sway distance (p = 0.029), and sway velocity (p < 0.001), particularly under eyes-closed single-leg stance. Posterolateral reach distance decreased (p = 0.023), accompanied by reduced lower-limb muscle activation. Tibialis anterior muscle reaction time during 30 degrees of inversion in the ankle neutral position was shortened (p < 0.001), whereas peroneus longus muscle responses were unchanged. Acute lower-limb BFR impairs ankle sensorimotor control by reducing proprioceptive accuracy, balance performance, and muscle activation, while shortening reaction time. These findings suggest caution when applying BFR during tasks that require high postural demands or end-range control. Registration number and date: NCT07307339, 12/26/2025.

Humans↗

PubMed2025

The effect of scopolamine on memory and attention: a systematic review and meta-analysis.

BACKGROUND: Scopolamine is a muscarinic receptor antagonist and is widely utilized as a "memory-loss model." However, its impact across different memory and attention tasks and using different modes of administration has yet to be clearly evaluated. This systematic review and meta-analysis investigates the effect of scopolamine, across all routes of administration and across different dosages, on memory and attention performance in healthy humans (PROSPERO ID: CRD42024531634). METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched (on 20 April 2024) for studies that utilized scopolamine and assessed memory and/or attention. Random-effects meta-analyses were conducted across a range of memory and attention tasks using "Comprehensive Meta-Analysis," Version 3, to evaluate differential pharmacological effects on cognitive tasks between the scopolamine and placebo groups. RESULTS: Forty-six studies fulfilled the inclusion and exclusion criteria. Scopolamine negatively impaired performance on all memory tasks (immediate memory, delayed recall, digit span, Buschke selective reminding task, and recognition memory) and led to slower reaction times for three of the five attention tasks examined (choice reaction time, simple reaction time, and rapid visual information processing) compared to placebo. Scopolamine's negative effect on memory and attention was greater with injectable (e.g., intramuscular, intravenous, and subcutaneous) compared to non-injectable routes of administration (e.g., intranasal, oral, and transdermal). CONCLUSION: This study supports the use of scopolamine as a "memory-loss model," particularly when given by an injectable route of administration. Future clinical trials should evaluate the bioavailability of scopolamine across different routes of administration to ensure therapeutic benefits outweigh any potential adverse cognitive effects.

Humans↗

PubMed2026

Effects of six weeks of guanidinoacetic acid supplementation with and without creatine monohydrate on cognitive function and markers of health in healthy adults.

BACKGROUND: Guanidinoacetic acid (GAA) supplementation has been reported to increase brain creatine content more effectively than creatine monohydrate (CrM). However, the effects on cognitive function are unclear. PURPOSE: The purpose of this proof-of-concept exploratory clinical trial was to determine whether GAA supplementation with and without CrM affects cognitive function and/or markers of health. METHODS: In a double-blind, randomized, and counterbalanced manner, 58 healthy and active adults (33 females, 35.5 ± 14 years, 76.2 ± 14 kg) ingested a PLA (PLA, 2 × 6 g/d maltodextrin), GAA (2 × 1 g/d) + PLA (2 × 5 g/d), or GAA (2 × 1 g/d) + CrM (2 × 5 g/d) for six weeks. The participants donated fasting blood samples and completed a battery of tests and questionnaires assessing various aspects of function, mood, stress, sleep quality, and markers of health at baseline and after six weeks of supplementation. Data were analyzed using General Linear Model (GLM) multivariate and univariate with repeated measures, and mean changes from baseline with 95% confidence intervals, and Chi-squared analysis, and considered significant when the probability of error was 0.05 or less, and approaching significance (p > 0.05-p < 0.10). RESULTS: GAA supplementation tended to improve overall reaction time (-241.8 ms [-533, 50], p = 0.10) while significant interaction effects were observed in overall reaction time (p = 0.031-330 ms [-629, -31]) and YES reaction time (-290 ms [-484, -96], p = 0.004) while recalled correct reaction time (-178 ms [-374, 21], p = 0.078) and recalled correct YES (7.4 % [-1, 15.8], p = 0.084) approached significance compared to PLA. Limited to no effects were observed on the Delayed Picture Recognition Task Test, Digit Vigilance Task Test, Corsi Block Task Test, or Stroop Color-Word Task Test. The amount of time engaged in moderate physical activity was significantly greater (p < 0.05) in the GAA group compared to PLA. Participants in the GAA group reported a lower frequency of controlling irritations (p = 0.036), and feeling like difficulties are mounting (p = 0.053) on the Perceived Stress Scale. Some positive and potentially undesirable effects were observed in sleep quality assessments. The quality of life assessment revealed that participants in the GAA group reported less frequent feelings of being worn out (p = 0.068) and that their health was excellent (p = 0.092) while those in the GAA + CrM group reported more frequent limitations when bending, kneeling, or stooping (p = 0.053), more often feeling full of life (p = 0.081), and less frequency in feeling downhearted and depressed (p = 0.066). No clinically meaningful changes were observed in blood markers or self-reported side effects among the groups. CONCLUSION: Dietary supplementation with GAA (2 g/d) and the combination of CrM (10 g/d + GAA 2 g/d) for six weeks improved delayed verbal episodic recognition memory and retrieval speed and some measures of perceived stress, sleep quality, and quality of life. However, most cognitive tests were not affected, particularly when comparing the GAA to the PLA group; there were some inconsistencies in the findings, and several differences only approached significance. Additional research is needed before conclusions can be drawn. Clinical trial registration: ISRCTN68542582.

Humans↗

PubMed2026

Effects of anodal transcranial direct current stimulation over the right primary motor cortex on a sequential motor finger tapping task in developmental stuttering.

INTRODUCTION: This study investigates the impact of anodal transcranial direct current stimulation (tDCS) on non-speech sequential motor practice in adults who stutter (AWS), compared to non-stuttering controls (ANS). Recent research has explored the effects of tDCS on speech fluency in stuttering. However, its effect on non-speech motor tasks has not yet been studied. METHODS: 20 AWS and 30 ANS right-handed participants were randomly assigned to anodal or sham tDCS conditions, performing a sequential finger tapping task. We targeted over the right primary motor cortex, stimulating at 2 mA for 20 min. Sequence duration and reaction time were analyzed. RESULTS: AWS analysis revealed that the anodal condition had significantly slower reaction times in the second half of the task compared to sham. For sequence durations, AWS in the anodal condition had slower overall sequence durations than the sham condition. However, there were no block-by-block differences in sequence duration. When comparing AWS and ANS, no significant differences were observed for sequence duration. However, there were significant differences in reaction time between AWS and ANS, specifically in earlier blocks. Additionally, there was no significant Group × Condition interaction. DISCUSSION: The findings suggest that anodal stimulation impeded finger sequencing in AWS, showing overall slower sequence durations and a diminishing effect on reaction times in the second half of the experiment, suggesting anodal tDCS may interact uniquely with the neural mechanisms in stuttering. Future studies should explore the effects of anodal tDCS on non-speech motor tasks to gain a broader understanding of its impact on motor control and motor learning.

Humans↗

PubMed2026

Virtual Reality Mastoidectomy as Precadaver Training for Novices: A Randomized Crossover Study.

OBJECTIVES: To compare cognitive load during virtual reality (VR) simulation and cadaveric dissection (CD) mastoidectomy training in novice learners. To determine whether training order influences cognitive load, characterize cognitive load progression during the procedure, and assess whether VR training improves subsequent cadaveric performance. METHODS: In this randomized crossover study, 24 core surgical trainees with no prior mastoidectomy experience performed a cortical mastoidectomy in both VR and CD settings. Participants were randomized to either VR-first or CD-first training sequences. Cognitive load was measured using a bespoke auditory reaction-time device at baseline and 10, 30, and 50 min. Relative reaction time (RRT) served as an objective index of cognitive load. Cadaveric performance was assessed using the Modified Welling Scale by two blinded otologists. RESULTS: Cognitive load was significantly lower during VR than CD, with mean RRT rising 26% from baseline in VR versus 60% in CD (p < 0.001). Training order did not affect cognitive load in either modality, and RRT increased progressively throughout mastoidectomy in both VR and CD. Participants who began with VR achieved significantly higher cadaveric performance scores than those who began with CD (mean 9.50 vs. 4.96; p < 0.001), and inter-rater reliability for performance scoring was high. CONCLUSION: VR mastoidectomy reduces cognitive load and enhances subsequent cadaveric performance in novice trainees, supporting its role as a cognitively optimized precadaver training modality that complements, rather than replaces, cadaveric dissection. These findings suggest VR enhances early learning efficiency and resource utilization in novice otolaryngology training. LEVEL OF EVIDENCE: N/A.

Humans↗

PubMed2026

Temporal redistribution of control reveals age-related differences in task switching at the level of preparation.

Task-switching studies often report minimal age-related differences in switch costs, leading to the conclusion that switching-related control processes are relatively preserved in aging. However, this conclusion is based on paradigms that confound preparatory and execution processes. This study examined whether age-related differences in semantic task-set reconfiguration may be underestimated due to this confound. In Experiment 1 (36 young and 30 older adults), participants performed an externally paced task-switching paradigm without control over preparation. In Experiment 2 (28 young and 28 older adults), a self-paced paradigm allowed participants to initiate stimulus onset, enabling measurement of preparation time. Across both experiments, reaction time (RT) and error rate (ER) showed reliable age effects but no interactions between age and condition, whereas switching-related condition effects varied across measures and experiments. The expression of switching-related costs differed across measures and task structures. Local switch costs were expressed in ER in Experiment 1 but in RT in Experiment 2. Global switch costs (all-switch vs. all-repeat) were observed in execution measures only in Experiment 1. In Experiment 2, preparation time showed reliable mixing, local, and global switching effects, with age-related amplification emerging specifically for global switching. These findings indicate that switching-related costs are redistributed across processing stages and behavioral measures. The results suggest that age-related modulation of semantic task-set reconfiguration may emerge more clearly during preparation than task execution, particularly under continuous switching demands. Preparation time is interpreted cautiously as reflecting participant-regulated preparatory processes rather than a pure measure of preparation efficiency.

Humans↗

PubMed2026

Alternative quadruplex real-time PCR reactions for detection and discrimination of Streptococcus pneumoniae serotypes within serogroup 6.

UNLABELLED: Streptococcus pneumoniae causes significant morbidity and mortality worldwide, and serotyping is important to assess the burden of disease that is vaccine preventable. For serotyping, the Centers for Disease Control and Prevention (CDC) use a series of 12 real-time multiplex PCRs (rmPCRs) performed in quadruplex reactions; however, rmPCR reaction 5 (rmPCR-5) for serotypes 6A, 6B, 6C, and 6D often failed at low DNA concentrations. This study investigated the cause of rmPCR-5 failure and provided alternative rmPCRs to resolve this issue. Quadruplex rmPCR target sequences were compared to S. pneumoniae reference genomes. Reactions rmPCR-5 [6ABCD, 6AB, 6BD, and 6CD] and rm-PCR-11 [37, 10F, 11BC, and 18CFBA] were compared to alternative reactions rmPCR-A1 [6ABCD, 10F, 11BC, and 18CFBA] and rmPCR-A2 [37, 6AB, 6BD, and 6CD]. All rmPCRs were tested using 10-fold serial dilutions of DNA from representative serotypes, and analytical specificity was assessed using DNA from other S. pneumoniae serotypes or various streptococci and Gram-positive cocci. Failure of rmPCR-5 was associated with overlapping 6ABCD and 6BD targets. Separation of these targets in the alternative rmPCRs-A1 and rmPCR-A2 allowed sensitive and specific detection and discrimination of serotypes 6A, 6B, 6C, and 6D, without impacting the detection of serotypes 10F, 11BC, 18CFBA, and 37. This study highlights the importance of rigorous author and peer-review to avoid manuscript errors and unintended consequences. By explaining what caused rmPCR-5 failure and proposing alternative reactions rmPCRs-A1 and rmPCR-A2, this study demonstrates the value of scientific collaboration to ensure molecular assays best serve the scientific community. IMPORTANCE: Streptococcus pneumoniae is a bacterium that can cause life-threatening infections like pneumonia and meningitis, leading to millions of deaths worldwide each year. A key feature enabling S. pneumoniae to cause disease is its sugar coating, allowing it to avoid the immune system. These surface sugars are the target of S. pneumoniae vaccines. However, vaccines only protect against some sugars and understanding which ones are on the surface of S. pneumoniae is called "serotyping." The Centers for Disease Control and Prevention (CDC) have protocols that allow us to predict S. pneumoniae serotypes by looking at its DNA. We found errors in the CDC protocols and provided a simple solution to fix them. Ultimately, having accurate serotyping protocols allows us to know how much disease is preventable by vaccine, allows us to monitor how well vaccine are working, and helps develop new vaccines if needed.

Streptococcus pneumoniae↗

PubMed2026

Six weeks of isometric resistance training led to evidence of corticospinal but not reticulospinal adaptation in previously untrained adult males.

The latest hypothesis regarding the source of enhanced neural activation from resistance training is the reticulospinal rather than the corticospinal tract, based on invasive animal and emerging human data. The present study employed a six-week isometric resistance training intervention in a randomized controlled design to address this knowledge gap. Thirty-nine healthy, untrained males (age ~23 y, sustained contraction group n = 13, explosive contraction group n = 9, control group n = 17) underwent neuromuscular and electrophysiological testing and completed all study requirements. Maximal isometric torque (MVC) and rate of torque development (RTD) were measured during a familiarization session as well as before and after the six-week period. Transcranial magnetic stimulation was used to assess motor-evoked potential (MEP) area and silent period duration while subjects contracted to 10% of MVC. Loud sound (120 dB) was used to modulate MEP area and reaction time to visual stimuli during the StartReact test. Only the intervention groups demonstrated significant improvements in MVC (27%) and RTD (60%) (both P < 0.01), along with reduced MEP area (- 21%) and silent period duration (- 23%) (both P < 0.01). The sustained contraction group showed reduced modulation of reaction time and increased MEP suppression due to loud sound. Short-term resistance training seemed to reduce cortical inhibition and corticospinal excitability in both training groups. The study showed conflicting changes in measures purported to evaluate reticulospinal functioning. It is recommended to examine different forms of resistance training and longer training exposure in future.

Humans↗

PubMed2026

The effect of combining visuo-vestibular exercises with manual therapy and exercise on sensorimotor function in chronic neck pain: A randomized controlled trial.

OBJECTIVE: To investigate whether adding visuo-vestibular exercises to standard manual therapy and exercise produces superior improvements in sensorimotor function, pain, balance, and functional disability in adults with chronic neck pain. METHODS: This prospective, randomized controlled trial enrolled 58 adults with chronic neck pain (≥3 months) allocated to a manual therapy and exercise group (MtE; n = 29) or MtE plus visuo-vestibular exercises (MtE-VVE; n = 29). Both groups completed 12 supervised sessions over six weeks with a daily home exercise programme. Outcomes were assessed at baseline, 6 weeks, and 12 weeks, and included pain intensity (Visual Analog Scale [VAS]), upper extremity reaction time, computerized posturography, the Neck Disability Index (NDI), and cervical muscle endurance. RESULTS: Fifty-four participants (27 per group) completed the study. Both groups improved significantly across all outcomes (p < 0.001). At 12-week follow-up, the MtE-VVE group demonstrated superior outcomes: activity-related pain was reduced by an additional 2.00 cm (95% CI: 0.75-3.25; p = 0.005), bilateral reaction time improved by 1.70 s (p = 0.001), eyes-open mediolateral sway decreased by 0.50 mm (p < 0.001), NDI score was 6.30 points lower (95% CI: 3.42-9.18; p < 0.001), and cervical flexion and extension endurance improved by 12.00 s and 27.70 s, respectively (p ≤ 0.020). CONCLUSION: Adding visuo-vestibular exercises to standard manual therapy and exercise produces clinically meaningful and sustained improvements in activity-related pain, sensorimotor function, postural control, and functional disability in adults with chronic neck pain, and may be recommended as an effective adjunctive intervention.

Humans↗

PubMed2026

The genetic overlap between schizophrenia and major depression with cognitive function.

This study aimed to systematically dissect the shared genetic basis of schizophrenia (SCZ) and major depression (MD) with cognitive function. To investigate this, we integrated large-scale genome-wide association studies (GWAS) summary statistics for SCZ (N = 175,799, [cases, 74,776; controls, 101,023]), MD (N = 2,622,273 [cases, 550,355; controls, 2,071,918]) and four cognitive traits (reaction time, N = 330,069; memory, N = 112,067; verbal-numerical reasoning, N = 36,035; educational attainment, N = 111,114). Linkage disequilibrium (LD) score regression analysis revealed that SCZ showed significant negative genetic correlations with reaction time, memory, and verbal-numerical reasoning. MD showed negative genetic correlations with memory, verbal-numerical reasoning, and educational attainment. Bayesian colocalization analysis identified seven genomic regions with strong or supportive evidence between SCZ and cognitive function, and two genomic regions with supportive evidence between MD and cognitive function. Gene mapping and over representation analysis (ORA) indicated that SCZ-associated genes were primarily involved in pathways related to transport processes, and MD-associated genes were significantly enriched in pathways related to neural development. Through genetic correlation and colocalization analysis, this study elucidates the genetic overlap between SCZ and MD with cognitive function, providing a new perspective for related research.

Journal Article↗

PubMed2026

Post-weaning social isolation increases reward-seeking behavior in mice.

Social isolation is a growing public health concern. Although isolation at any age is harmful, previous studies have shown that isolation during adolescence, correlating with critical periods of brain development, can impair cognitive function and increase the risk for psychiatric illness later in life. In this study, we utilized a mouse model of social isolation (SI) during adolescence (postnatal day 21-35) and compared performance of isolated and group-housed mice on a touchscreen-based continuous performance test (rCPT) and fixed ratio/progressive ratio (FR/PR) tasks in adulthood. SI improved performance in the rCPT and the improvement in performance was consistent across time bins within the 45-minute testing session. There were no effects of SI on reaction times or reward retrieval latencies. A possible confound for performance in the rCPT would be SI-induced changes in reward-seeking or motivation for the strawberry milk reward. We next compared the SI mice to their group-housed littermate controls on both PR and FR schedules of reinforcement and found that SI mice had higher breakpoints on a PR4 schedule and earned significantly more reinforcers on an FR1 schedule of reinforcement compared to their group-housed littermates, suggesting that high performance in the CPT may be due to increased motivation for food rewards. These data indicate that SI during adolescence has significant effects on reward-seeking behavior in adult mice and may provide a useful behavioral model for studying the link between SI and risk for neuropsychiatric disorders.

Animals↗

PubMed2026

Game changer? Cognitive-motor effects of VR exergaming compared to video-based training.

BACKGROUND/OBJECTIVE: Virtual reality (VR) exergaming enhances several cognitive domains through multisensory engagement. Acute cognitive benefits of VR are established, but evidence for direct comparisons with non-immersive controls is limited. This study aimed to determine whether VR exercise provides additional cognitive and cognitive-motor benefits beyond a matched non-immersive active stick-fight video (SFV) intervention, and whether effects persist after training. METHODS: In this randomized quasi-experimental study, N = 55 healthy adults (VR: n = 30; SFV: n = 25; 25.5 ± 7.1 years; 41.8% female) completed an 8-week program (2 × 30 min/week), of VR or SFV matched in movement patterns, frequency, intensity and duration. Measurements included reaction time (RT), Stroop Test (versions 1-3), Letter Cancellation Test (LCT), Trail Making Test (TMT), Trail Walking Test (TWT) and Fitts task (difficulty level 1-4). Data were analyzed using mixed-design ANOVAs. RESULTS: Improvements were observed in Stroop reading (F(1,53) = 14.84, p < .001, η2 = 0.219), Stroop inhibition (F(1,53) = 10.99, p = .002, η2 = 0.172), and LCT (F(1,53) = 4.57, p = .037, η2 = 0.079). A time × group interaction was found for TMT (F(1,53) = 6.55, p = .031, η2 = 0.110), indicating greater changes following VR training. Both groups improved cognitive-motor performance (TWT: F(1,25) = 55.32, p < .001, η2 = 0.689; Fitts3: F(1,53) = 44.97, p < .001, η2 = 0.459), with greater gains for VR in Fitts3 (p = .006). CONCLUSION(S): Eight weeks of VR and SFV enhanced cognitive and cognitive-motor performance. VR provided domain-specific advantages in executive function, but these effects were not uniformly persistent. SFV sustained more improvements in real-world-relevant cognitive-motor tasks.

Humans↗

PubMed2026

Dissociating behavioral, neural and experiential effects of prefrontal HD-tDCS during conflict resolution.

Inconsistent evidence regarding the cognitive effects of transcranial direct current stimulation (tDCS) highlights the need for more comprehensive approaches to assess its impact. This study aimed to investigate the effects of high-definition tDCS (HD-tDCS) on conflict resolution by combining behavioral, neural, and subjective experience measures. Sixty participants were randomly assigned to anodal, cathodal, or sham HD-tDCS groups and completed a 30-min flanker task. EEG was recorded during the first and last blocks (without stimulation), while stimulation was applied during the intermediate blocks of the task. Using a multidimensional methodological approach including Drift-Diffusion Modeling (DDM), EEG spectral analysis, Lempel-Ziv complexity, and Temporal Experience Tracing (TET), we assessed the cognitive, neural, and phenomenological effects of stimulation. Behavioral results indicated no significant improvements in reaction times or accuracy across the stimulation groups. Similarly, DDM parameters showed no effect of HD-tDCS on latent cognitive processes. However, EEG data revealed a significant reduction in neural complexity in the anodal group during resting-state, suggesting a stabilization or reorganization of neural dynamics. Subjective experience analysis identified two distinct clusters of task-related feelings, though time spent in these experiential states did not differ between groups. Interestingly, sensation of stimulation was significantly higher for anodal stimulation than sham when analyzed as a single dimension. Despite null behavioral effects, this study provides important insights into the neural and subjective responses to HD-tDCS and highlights the value of integrating complementary multidimensional approaches to better characterize brain stimulation effects. These findings contribute to the ongoing debate about the efficacy of tDCS in cognitive enhancement.

Humans↗

PubMed2026

Effects of acute resistance exercise on prefrontal oxygenation and task-switching performance: Considerations of loading strategies and blood flow restriction.

Although acute resistance exercise (RE) has been proposed to influence cognitive flexibility and underlying neural mechanisms, it remains unclear whether these effects vary across loading strategies and whether exercise-induced prefrontal hemodynamic responses translate into cognitive outcomes. The present study examined (1) prefrontal cortex (PFC) oxygenated hemoglobin (O2Hb) responses across exercise sets and conditions, (2) the effects of low-load (LL), LL with blood flow restriction (BFR), and high-load (HL) RE on task-switching performance, and (3) whether exercise-related PFC O2Hb responses were associated with pre- to post-exercise changes in task-switching performance. Thirty physically active adults completed three randomized, counterbalanced RE conditions consisting of four sets of barbell squats. LL was performed at 30% one-repetition maximum (1RM) with and without BFR, whereas HL was performed at 70% 1RM. Cognitive flexibility was assessed pre- and post-exercise using a modified Stroop task, indexed by switch-cost reaction time (RT) and accuracy. PFC O2Hb was assessed using functional near-infrared spectroscopy during exercise and expressed as changes from the resting baseline for each set (Sets 1-4). PFC O2Hb increased across sets, rising from Set 1 to Set 3 before plateauing, with no differences observed across conditions. Switch cost RT and accuracy did not improve from pre- to post-exercise, and no differences across conditions were detected. PFC O2Hb during the final set was not associated with changes in switch cost. These findings suggest that although acute RE elicits robust increases in prefrontal hemodynamic activity, such responses may not translate into acute improvements in cognitive flexibility.

Humans↗

PubMed2026

Catecholaminergic Contributions to Inhibitory Control Following Physical Fatigue: Behavioral and Neurophysiological Findings.

Acute physical fatigue can impair cognitive control, yet its underlying neurochemical mechanisms remain unclear. This study investigated whether catecholaminergic modulation influences behavioral and neural markers of inhibitory control following physical fatigue. Eighteen healthy, recreationally active adults (9 males, 9 females; 23.4 ± 2.2 years) completed a randomized, triple-blind, placebo-controlled crossover study. On separate visits, participants received methylphenidate (MPH; 20 mg; a dopamine and noradrenaline reuptake inhibitor), reboxetine (REB; 8 mg; a noradrenaline reuptake inhibitor), or placebo. Physical fatigue was induced by repeated bilateral leg extensions to task failure. Cognitive performance was assessed before and after physical fatigue using a Go/No-Go task with electroencephalographic recording. Behavioral outcomes included reaction time and accuracy, while event-related potentials measured neural stages of response execution and inhibition (N2 and P3). Mixed-effects models were used for statistical analysis. For No-Go trials, a significant MPH × Time interaction was observed for accuracy (p = 0.008), with improved post-fatigue performance following MPH administration (p = 0.048). At the neural level, MPH was associated with shorter fronto-central No-Go N2 latency (p = 0.038) and altered fatigue-related changes in No-Go P3 latency (p = 0.047). REB did not produce comparable behavioral or neural effects. These findings provide pharmacological evidence that catecholaminergic mechanisms contribute to inhibitory control following physical fatigue. The differential effects of MPH and REB suggest that selective noradrenergic enhancement alone is insufficient to maintain inhibitory control following physical fatigue. Instead, the findings implicate broader dopaminergic and noradrenergic mechanisms, potentially involving alterations in the temporal dynamics of inhibitory processing. TRIAL REGISTRATION: (G095422N and identifier NCT05880342).

Adult↗

PubMed2025

Pupil dynamics in macaque recognition memory tasks: investigating physiological mechanisms.

Cognitive deficits are common in primates, particularly in memory and emotional processes. Rhesus monkey (Macaca mulatta), widely used in cognitive and behavioral research, are central to memory studies. The relationship between recognition memory performance and pupillary dynamics in rhesus monkeys remains underexplored. This study investigated pupil dynamics during recognition memory tasks and their physiological correlates in five sexually mature male rhesus monkeys. We measured pupil diameter and oscillatory features during tasks and analyzed the relationship between behavioral performance and physiological indicators. We found that the average correct response rate exceeded the random success level, and reaction times were significantly shorter during successful recognition than failures, highlighting their cognitive efficiency. During recognition of familiar scenes, average pupil diameter increased, while maximum change in pupil size decreased, indicating reduced cognitive load. Both the frequency and amplitude of pupillary oscillation were lower during successful trials, reflecting decreased cognitive conflict and effective processing. This change reflects a decrease in cognitive conflict and suggests that information processing was more effective. The absolute value of the pupil peak slope decreased during successful recognition, indicating more stable cognitive state. These results support that pupillary dynamics can serve as physiological markers of cognitive effort in rhesus monkeys. Future studies should investigate how stimulus characteristics influence recognition and incorporate measures, such as intracranial EEG and fMRI, to enhance our understanding of their neural mechanisms. This research supports the rhesus monkey model in cognitive neuroscience and contributes to understanding primate cognition and its physiological foundations, with implications for clinical and translational research.

Animals↗

PubMed2026

Acute effects of AT1 receptor blockade on approach-avoidance of negative emotional faces.

Recent evidence implicates the renin angiotensin system (RAS) in various cognitive markers of depression, including dysfunctional reward processing. Yet, it remains unknown whether these effects extend to other markers implicated in depression and its treatment, such as approach-avoidance motivations that reflect innate drives to approach reward and evade harm. We sought to examine the impact of acute losartan, an angiotensin type 1 (AT1) receptor blocker, on the implicit approach-avoidance of facial expressions and checkerboard controls in healthy adults. In a randomized controlled trial, N = 68 healthy adults aged 18-50 (49 F/19 M) were administered a single 50 mg dose of losartan or placebo before completing an implicit Approach Avoidance Task (AAT) at drug-peak level. On the AAT, participants responded to color-filtered facial stimuli (happy, sad, angry, or neutral) and checkerboard controls using a joystick, and were instructed to pull all gray photos and push all brown photos as quickly as possible. Compared to placebo, losartan induced a significant avoidance bias for sad faces (p = 0.027) and reduced avoidance of angry faces at trend level (p = 0.085). This occurred without significant group differences on blood pressure, overall reaction time, accuracy, and approach-avoidance biases for other stimuli. The response pattern associated with AT1 receptor blockade may counteract previously observed depressive tendencies, suggesting effects possibly consistent with antidepressant treatments. Our findings further highlight the RAS as a mechanistically relevant target for psychiatry, suggesting that AT1 receptor antagonism may have relevance for treating depression and other emotional disorders characterized by aberrant motivational biases (Clincialtrials.gov ID: NCT06624904).

Journal Article↗

PubMed2026

Bioinformatics and Quantitative Real-Time Polymerase Chain Reaction Analysis of SUCNR1 and GPR37L1 in Schizophrenia.

Schizophrenia is a severe, complex, and multifactorial mental disorder involving numerous genetic susceptibility elements, leading to substantial disability, morbidity, and mortality. Despite significant progress in understanding its pathophysiology and etiology, specific diagnostic biomarkers for schizophrenia remain elusive. This study aimed to identify candidate molecular markers associated with schizophrenia. An integrated bioinformatics analysis was performed on the public microarray dataset GSE54913. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the most significantly enriched GO terms were related to channel activity, including passive transmembrane transporter activity, ion channel activity, gated channel activity, and substrate-specific channel activity. The top five enriched KEGG pathways were insulin secretion, cAMP signaling pathway, nucleotide excision repair, TNF signaling pathway, and glutathione metabolism. Validation was conducted using quantitative real-time polymerase chain reaction (qRT-PCR) on an independent sample set from Wuhan Rongjun Youfu Hospital. The qRT-PCR results were largely consistent with the microarray analysis (Pearson r = 0.89, 95% CI: 0.66-0.97). Protein-protein interaction (PPI) network analysis identified two hub genes, SUCNR1 and GPR37L1, which were significantly associated with the GO term 'ion channel activity' and enriched in the KEGG pathway 'insulin secretion'. Furthermore, SUCNR1 expression showed a negative correlation with verbal memory scores (r = -0.54, P = 0.015), whereas GPR37L1 expression showed a positive correlation (r = 0.59, P = 0.0034). These findings suggest that altered SUCNR1 and GPR37L1 expression may be associated with schizophrenia and may represent candidate molecular markers for further investigation.

Humans↗