Experimental Brain Research最新文献

This is a randomized crossover study design. We examined the acute effects of prolonged social media use (SMU) vs. computerized Modified Stroop Task (MST) on electroencephalogram (EEG) spectral power and physical performance in taekwondo (TKD) athletes. Fifteen athletes underwent cognitive manipulations (SMU, MST, documentary [DOC]), followed by mental tiredness checks (Visual Analogue Scale [VAS]), EEG measurements, an intermittent TKD task, and psychobiological variables (heart rate [HR], rating perceived exertion [RPE]). Only MST significantly increased the VAS (p < 0.05). Theta power decreased in the parietal cortex after cognitive manipulations across conditions (p < 0.001). MST presented a time effect for theta, alpha 1, and alpha 2 in parietal cortex during the task at 15 min (ps < 0.004), diminishing over time. Physical performance declined throughout rounds (p < 0.001), more under MST vs. DOC (p = 0.03). RPE increased (p < 0.001); no significant difference in HR was found (ps > 0.07). High cognitive demand tasks may impair the performance of TKD athletes.

Interhemispheric inhibition (IHI) acts between hemispheres to decrease motor cortical excitability. IHI changes during movement preparation, but it is unknown whether altering IHI, independent of other factors, alters movement initiation. For the index finger abductor muscle (first dorsal interosseous; FDI), IHI is weaker during contralateral index abduction than adduction. Thus, this study aimed to modulate IHI through contralateral contraction and measure resultant changes in reaction time. Fifteen healthy participants (age 19-39 years) completed a reaction-time task requiring brief left index finger abduction. Prior to reactions, participants started either a sustained isometric abduction or adduction contraction of the right index finger. Single- or paired-pulse transcranial magnetic stimulation (TMS) elicited motor evoked potentials (MEPs) from left FDI in the late pre-movement phase. For each contralateral contraction direction, unconditioned and conditioned MEPs (preceded by suprathreshold TMS over the other hemisphere at 10 or 40 ms) were recorded. Conditioned MEPs, expressed relative to unconditioned MEPs, provided measures of short-interval IHI (SIHI) and long-interval IHI (LIHI). Left index finger reaction time was also measured. Linear mixed models showed that reaction time was 9 ± 9 ms (6%) slower during right adduction than abduction (F_1,1875 = 30.7, p < 0.001). Unconditioned MEPs in left FDI were 1.1 ± 2.0 mV (37%) smaller (F_1,270 = 8.82, p = 0.003) and SIHI 11 ± 16% stronger during right adduction (F_1,279 = 15.15, p < 0.001). However, LIHI was not different between right contraction conditions (F_1,272 = 0.410, p = 0.522). These results suggest that IHI can alter reaction time by influencing corticospinal excitability. Stronger SIHI during right adduction likely delayed pre-movement increases in corticospinal excitability, slowing reaction time.

Bupivacaine is a commonly used local anesthetic in both human and equine medicine. This study aimed to explore the molecular mechanism of bupivacaine-induced postoperative cognitive dysfunction (POCD). Bioinformatics analysis identified YES proto-oncogene 1 (YES1) as a key player. A POCD mouse model was developed using bupivacaine and surgery, followed by assessment of cognitive function and DNA damage. SH-SY5Y cells were exposed to bupivacaine, and DNA damage was analyzed. Verteporfin, a Yes-associated protein 1 (YAP1) inhibitor, was used in both mice and cells to study its effects. Bupivacaine increased escape latency and decreased the number of platform crossings in the Morris water maze test, and reduced total distance traveled in the open field test and discrimination index in the novel object recognition test, which was associated with the suppression of YES1 expression in the hippocampal tissue of mice. YES1 overexpression alleviated POCD and neuronal DNA damage induced by bupivacaine in mice by promoting YAP1 phosphorylation. Treatment with verteporfin reversed the alleviating effects of YES1 overexpression on neuronal DNA damage and exacerbated POCD in mice. In conclusion, bupivacaine induces POCD by suppressing YES1 expression and YAP1 phosphorylation, leading to DNA damage.

Gulf War Illness (GWI) affects approximately 30% of veterans who served in the 1991 Persian Gulf War and is characterized by chronic pain and fatigue, as well as cognitive, mood, gastrointestinal, and respiratory symptoms. Animal research has suggested that GWI is caused by a combination of neurotoxicants such as nerve gas, anti-nerve agent pills, and pesticides, though a definitive pathophysiological model has not been established. In this human observational study, 20 veterans with GWI and 20 healthy Gulf War veterans (HV) underwent whole-brain magnetic resonance spectroscopy to non-invasively measure several metabolites associated with neuroinflammation. Veterans also completed an arterial spin labeling scan to assess cerebral perfusion. Compared to HV, veterans with GWI demonstrated widespread decreases in brain choline, N-acetylaspartate, and creatine, and regional elevations in lactate and brain temperature. No group difference was observed in cerebral perfusion. Exploratory analyses revealed brain metabolites were associated with self-reported neurotoxicant exposures in theater. These findings support a role of cholinergic alterations and neuroinflammatory processes in GWI. Trial registration: The study was registered in ClinicalTrials.gov, ID NCT04638998. Registered November 16, 2020, https://clinicaltrials.gov/study/NCT04638998 .

The control of reaches to targets that vary in distance involves a combination of anticipatory planning and feedback-based adjustments. However, it is not known if their contributions to the control of reach extent change with repetitive practice. This study investigated the effect of three days of practice on the control of reach extent. Right-hand dominant participants reached with either the non-dominant left arm or dominant right arm to six targets presented in two directions and three distances in a virtual environment. The effect of practice on planning and feedback-based adjustments to control reach extent was examined by determining how well peak acceleration and time to peak velocity predicted the eventual distance moved, respectively. Both arm groups demonstrated improvements in reach performance (decreased endpoint error and movement time). The Left Arm group demonstrated an increased use of anticipatory planning and feedback-based adjustments to control reach extent with practice while the Right Arm group did not show a change. Changes in the control of reach extent seen in the Left Arm group may reflect experience-dependent creation of a more robust internal model of the arm and/or increased weighting of control mechanisms from the dominant left-brain hemisphere. The potential to modify the use of anticipatory planning and feedback-based adjustments to control reach movements may be relevant for rehabilitation approaches in clinical populations such as stroke who have altered control of reach extent.

Anticipatory postural adjustments (APAs) are generally understood to be cortically driven, however there is some evidence to suggest subcortical regulation and contribution. We tested the hypothesis that subcortical pathways, if contributing, would be evidenced in increased late portions of the motor evoked potential (MEP) elicited by transcranial magnetic stimulation during different time intervals before and during the APA. Recordings from both the tibialis anterior and soleus muscles showed little evidence for this throughout the course of the APA, pointing instead to a generally cortical source for the APA. Despite this, the brainstem did not appear inactive, with MEPs elicited during voluntary contraction of the soleus being significantly smaller than those elicited prior to executing an APA- specifically during the later portion of the MEP, thought reflective of subcortical contribution. Further work to isolate specific brainstem upregulation and contribution is needed.

Mental rotation can be performed more efficiently for objects that resemble the human body than for abstract objects. This human-body advantage is thought to reflect the involvement of body representations and motor processes. The present study investigated whether this advantage is reduced in older adults with knee osteoarthritis (OA), a condition associated with motor degeneration and altered body representation. Fifty-nine women with knee OA and thirty-six age-matched healthy controls completed a chronometric mental rotation task involving cube-shaped stimuli with or without a face. Results showed a significant human-body advantage in the control group but not in the knee OA group. This group difference remained even after controlling for body mass index and functional mobility, suggesting that the reduced advantage in the knee OA group may be associated with OA-related impairments such as disruptions in body schema or motor imagery. An exploratory analysis found no significant associations between the magnitude of the human-body advantage and clinical measures of knee OA severity (radiographic grade, symptom scores, gait-related self-efficacy, and functional mobility). These findings suggest that intact body representations may play a role in supporting the human-body advantage in mental rotation. They may also inform assessment of body representation in OA.

The ability to flexibly disengage and shift attention allows us to successfully interact with our environment and develops across infancy, childhood and adolescence. The aim of the present study was to investigate how attentional disengagement abilities develop. We leveraged a robust longitudinal dataset of the Gap-Overlap task of the YOUth cohort with over 3500 children tested at one or more timepoints to track the maturation of attentional control across infancy, childhood and adolescence (5 months, 10 months, 3 years, 6 years, 9 years, 12 years). While we replicated established group-level developmental patterns showing progressive improvement in saccadic reaction times, the time between the appearance of the target and the initiation of the saccade, our findings revealed individual variation in developmental trajectories of the gap effect that cannot be reliably predicted from performance at earlier timepoints. Although we found no associations between Gap-Overlap performance and (parent-reported) attention-related behaviors (n = 99-734 depending on age and measures), this may reflect the difficulty of identifying early markers in highly heterogeneous neurodevelopmental disorders and could be limited by examining subclinical traits rather than diagnosed conditions. The increased understanding of individual developmental patterns established here is a prerequisite for the identification of atypical patterns in clinical assessment. Future studies could build on this work by investigating atypical attention profiles across development and their relationship to Gap-Overlap task performance, particularly in clinical populations where attentional differences may be more pronounced.

Estimates of sound source distance are well described by a compressive function relating judged to actual distance; distance is systematically underestimated at larger distances. The current experiment investigated whether such compression is a general tendency of auditory distance judgments, by measuring the judged distance of silent objects based on a novel skill, using self-produced echolocation mouth clicks. The accuracy and precision of distance estimates were measured for aluminum or foam objects (the latter being less reflective than the former) positioned 30, 60, or 90 cm away from 11 blindfolded, normally sighted participants. The distance estimates were well characterized by compressive power functions. Distances were significantly more underestimated and consistency was significantly worse for the two closest object distances for foam than for aluminum objects. Systematic errors were similar for the two materials. The results are consistent with the idea that compression may be a general tendency of auditory distance judgments, both for sound-producing objects as observed in the literature and for silent objects whose distance is judged using a novel echolocation skill.

Ludic design in mental chronometry seeks to enhance engagement through socio-interactive elements. The present study examined whether a co-actor duel context influences both performance and subjective experience. Participants completed speeded arithmetic at two difficulty levels (easy, hard) under two context conditions (alone, duel) in a mixed within-subject design. Self-reports of engagement, distress, and worry were obtained before and after tasks. In the duel context, participants completed problems more quickly, accompanied by a small rise in errors, which however, remained far below the 10% margin allowed by duel rules, indicating that the increase was not a deliberate sacrifice of accuracy for speed. We interpret the speed-up as improved efficiency with preserved engagement, where the modest error rise reflects the probabilistic cost of reduced checking time rather than relaxed accuracy criteria. Such minor differences are unlikely to be consciously detected and therefore are not introspectable as a performance decline.