Experimental Brain Research最新文献

Mental fatigue (MF) has a significant impact on performance and decision-making in various contexts. It is considered a transient psychophysiological state characterized by impaired cognition and behavior across a range of dynamic contexts. This condition is related to changes in activity and connectivity across certain brain regions. Despite advances in understanding MF, the neural mechanisms remain unclear, necessitating further investigation. This systematic review synthesizes task-based fMRI evidence on MF during prolonged tasks, identifies convergent activation patterns and methodological gaps, and outlines possible future research. Following PRISMA, we searched PubMed, Web of Science, PsycINFO and Embase until November 6th, 2025. Eligible studies involved healthy participants, a mentally fatiguing task ≥ 30 min, and task-based BOLD fMRI acquired either on-task or in pre/post designs. Study characteristics and fMRI findings were extracted; risk of bias was appraised with NIH tools. Nine studies (n = 235) met the inclusion criteria. Across both designs an increase in MF was recurrently linked to higher activation in prefrontal and salience-related regions (DLPFC/VLPFC/DMPFC, ACC, insula) and the thalamus, while tendencies towards deactivation in posterior cortices (parieto-occipital/precuneus) were observed. Some studies also reported cerebellar effects. This review demonstrates the complexity of the neural correlates of MF and underscores the need for comprehensive research to understand its impact on brain functioning.

The thumb plays a crucial role in hand function, yet its proprioceptive abilities remain poorly understood. Here we quantified dynamic thumb localization ability, as well as how this ability adapts to a perturbation, in unimpaired participants. For this, we developed a novel task in which a robot moved the thumb in a circle and participants pressed a button when they felt their thumb aligning with a target point on a screen, receiving visual error feedback in the form of a ball jumping toward the target after they pushed the button. The task also incorporated a propriovisual rotational perturbation to elicit and measure adaptation. To characterize thumb localization ability, we varied thumb speed and rotation diameter, assessed the effect of the propriovisual rotational perturbation, and compared index finger performance. Following task familiarization, average thumb localization error was relatively consistent, with a constant error (CE) of - 5.9°, variable error (VE) of 25.2°, and absolute error (AE) of 29.2°. Errors did not change significantly with speed or circle diameter. Reversing thumb rotation temporarily increased error followed by rapid error adaptation across the next 20 trials, as would be expected if individuals adapted using a body-centered (movement-aligned) frame of reference rather than a world-centered spatial frame. Localization error was comparable for the thumb and the index finger error for the same task and was correlated with a different, robotic assessment of finger proprioception (ρ = 0.61, p = 0.001). These findings indicate that dynamic thumb localization is somewhat inaccurate, although it can leverage visual feedback within a body-centered reference frame to adapt. Further, in unimpaired adults, the dynamic localization abilities of the thumb and index finger are related.

To explore the association between lymphocyte to high-density lipoprotein ratio (LHR) and pain in Parkinson's disease (PD). In this cross-sectional study, 133 inpatients with PD (84 with pain, 49 without pain) were consecutively recruited. Demographic, clinical, and peripheral immune-inflammatory markers were compared between PD patients with and without pain. Risk factors were identified through binary logistic regression. The independent association of the LHR with pain was assessed using multivariable logistic regression, with progressive adjustment for demographic, clinical, and comorbidity factors. Subgroup analyses were conducted to assess the consistency of the association across different clinical subgroups. Compared with patients without pain, those with pain had higher levodopa equivalent daily dose, more severe motor symptoms, greater levels of anxiety, depression, and sleep disturbances, along with elevated LHR. Binary logistic regression identified LHR (odds ratio [OR] = 3.64, 95% confidence interval [CI] 1.56-8.49, P = 0.003) as independent risk factors for pain. In the multivariable model, adjusted for key covariates including age, sex, disease duration, and major comorbidities, LHR remained a significant and independent risk factor (adjusted OR = 4.50, 95% CI 1.77-11.47, P = 0.002). Subgroup analyses confirmed the stability of this association across age, sex, body mass index, hypertension, diabetes, disease duration, and age at onset, with no significant interactions observed (P > 0.05). In this observational study, a higher LHR was positively associated with pain in PD. Future studies should validate these findings and explore LHR-based interventions.

Previous research has shown that different grasping actions selectively influence the processing of simple visual features based on their relevance to the specific action. However, it remains uncertain if this interaction extends to higher-order information, such as the global configuration extracted from an array of visual elements. The present study investigated the impact of different grasping types on the processing of configural shape information in visual working memory (VWM). In Experiment 1, participants engaged in a VWM change detection task while producing either power- or precision-grasping actions. The availability of configural shape information was manipulated through the presence or absence of surrounding circles around oriented bars. The results showed that configural shape information in the memory array overall benefited participants' change detection performance. Importantly, the effect of configural shape on memory performance was modulated by grasping type, with a greater configural benefit under precision-grasping compared to power-grasping. Experiment 2 replicated those findings under different task demands that required maintaining the grasp postures, while controlling for differences in the physical appearance of stimuli across conditions. Together, the findings highlight the role of grasping type in modulating the processing of configural shape information: different grasping actions influence how configural shape information is encoded and maintained in visual working memory.

The aim of this study was to evaluate hand muscle strength, dexterity and hand sensation in individuals with type 2 diabetes with and without peripheral neuropathy. The study was completed with a total of 57 patients with diabetic peripheral neuropathy (DPN+) (n = 31) and without diabetic peripheral neuropathy (DPN-) (n = 26). Semmes-Weinstein Monofilament Test (SWMT) was used for light touch sensation, 128 Hz tuning fork for vibration sensation, esthesiometer for two-point discrimination sensation, Baseline hydraulic hand dynamometer for rough grip strength, Baseline pinch meter for finger pinch strength, and 9-hole peg test (NHPT) for manual dexterity. When light touch sensation was examined in DPN+ and DPN- groups, a significant difference was found between the groups (p < 0.05). When two-point discrimination sense was evaluated between the DPN+ and DPN- groups, it was found to be significant in favor of the DPN+ group in the 1st finger of the right hand and 2nd and 3rd fingers of the left hand (p < 0.05). Rough grip strength values ​​were found to be significantly lower in the DPN+ group in both hands (p < 0.05). In the DPN+ group, left 1st and 2nd finger pinch strength values ​​were found to be statistically significant (p < 0.05). Manual dexterity values ​​were significantly higher in the DPN+ group (p < 0.05). Peripheral sensory nerve involvement in diabetic patients reduces hand grip strength and hand function. Understanding these connections between diabetes, sensation, and muscle strength is important for developing targeted interventions and rehabilitation strategies to help diabetic patients maintain their quality of life.

The transmission of pain signals through the spinal cord can cause structural and functional changes in the brain, which may contribute to diverse symptoms. Since the early 19th century, researchers have been studying hemispheric asymmetries in the brain and their effects across different species. However, it remains unclear whether pain-related emotional and cognitive changes are differently affected by left- and right-sided pain. To address this question, we conducted a study comparing the performance of chronic neuropathic mice with left or right spared nerve injury (SNI) in various behavioral tests. We evaluated their behaviors in the open field (OF), Y-maze, novel object recognition, and fear conditioning tests, and compared their performance to that of sham mice. Compared with sham mice, SNI mice manifested mechanical allodynia. In the OF test, SNI-L mice showed an increased anxiety-like profile compared to the other groups. Both left- and right- sided SNI mice showed cognitive deficits to a similar degree in memory tasks. Our results revealed that unilateral chronic neuropathic pain differentially affected anxiety condition, but not pain threshold and cognitive function.

Musical meter emerges from the hierarchical organization of beats, which is influenced by both external acoustic cues and internally driven processes. This study examines neural and behavioral responses to auditory sequences when two simultaneous grouping patterns, melodic repetition and intensity accents, are candidates to establish a ternary or quaternary metrical representation. We also investigated how tonal coherence and tempo affect these metrical representations. To do so, we recorded finger tapping responses and electroencephalograms (EEG) from musically-naïve participants while they listened to musical sequences. The frequency-tagging analyses of the EEG indicated that melodic repetition, compared to intensity accents, enhances neural synchronization to metrical groupings. In contrast, disrupting tonal coherence with microtonal intervals reduces neural responses to both grouping patterns. No neural synchronization to any of these patterns was observed during a grouping-continuation imagery task. Behavioral data from the tapping task revealed a strong preference for quaternary over ternary groupings. These findings provide evidence that a repeating melodic pattern can establish neural responses to its periodicity, which likely scaffolds a metrical representation of the rhythmic sequences in the brain through complex interactions between bottom-up and top-down mechanisms in the formation of musical meter.