Experimental Brain Research最新文献

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.

Deubiquitinating enzymes of the ubiquitin-specific peptidase (USP) family have been increasingly recognized for their roles in modulating neuropathic pain. In this study, bioinformatic analysis identified USP19 as a downregulated gene in trigeminal neuralgia (TN). Using a mouse model of TN induced by foramen lacerum impingement of the trigeminal nerve (FLIT), we demonstrated that adeno-associated virus-mediated overexpression of USP19 in the cerebral cortex significantly alleviated anxiety-like and pain-like behaviors. USP19 overexpression promoted deubiquitination and stabilization of fused in sarcoma (FUS), as confirmed by Western blotting, actinomycin D treatment, and ubiquitination assays. In HT22 and SH-SY5Y cells exposed to lipopolysaccharide to induce mitochondrial dysfunction, USP19 restored mitochondrial membrane potential, reduced mitochondrial reactive oxygen species, suppressed DRP1 phosphorylation, and upregulated CYTB and ND4 levels. These effects were reversed by FUS knockdown, both in vitro and in vivo. Moreover, FUS silencing abolished USP19-mediated improvements in NAD⁺/NADH ratio and mitochondrial function, as well as its analgesic and anxiolytic benefits in TN mice. These findings suggest that USP19 alleviates TN by enhancing FUS deubiquitination and preserving mitochondrial integrity in neurons. This study reveals a novel USP19/FUS signaling axis in the regulation of mitochondrial homeostasis and provides a promising therapeutic target for the treatment of TN.

This study aims to explore the neural impact of virtual reality (VR) motion sickness on individuals from the perspective of brain functional networks, analyze the relationship between changes in Electroencephalogram (EEG) frequency bands and VR motion sickness, and provide a new perspective for evaluating the neural excitation mechanism of VR motion sickness. Twenty-six subjects were grouped based on their sensitivity to VR by a subjective evaluation scale. EEG signals were recorded before and after VR experiment. Functional brain networks were constructed and the changes in perspective of network topological characteristic parameters were analyzed. Participants in the sensitive group exhibited increased clustering coefficients and local efficiencies in the Delta band, as well as increased characteristic path lengths in the Alpha band. Conversely, subjects in the insensitive group exhibited no substantial alterations in brain network parameters before and after the VR experiment, and no significant changes in other frequency bands. The result indicate that alterations in the Delta and Alpha frequency bands play a crucial role in the mechanism of VR-induced motion sickness. These changes reflect an augmentation of the brain's local information processing capacity in response to VR motion sickness, as well as modifications in the efficiency of the global network in processing visual stimuli and modulating attention. These findings provide theoretical underpinnings for the neurological effects of VR motion sickness and establish a foundational framework for future research.

Mental fatigue is a psychobiological state brought on by long periods of demanding cognitive activity and can impact cognitive performance. The aim of this study was to determine whether mental fatigue affects decision-making performance (response time and accuracy) during a collision avoidance task. Twenty-six young adults were randomly assigned to either a mental fatigue or a control group. In a virtual environment, participants approached a 90 cm doorway while a virtual person approached from the opposite side. As participants reached two meters from the doorway, the screen went blank, and they were instructed to respond as quickly and accurately as possible whether they would pass through the doorway first. The virtual person approached at four different speeds relative to the participant's average walking speed (i.e. 0.8×, 0.9×, 1.1×, and 1.2×). After completing 20 trials, the mental fatigue group completed a 30-minute Stroop task while the control group watched a 30-minute documentary, followed by another block of the crossing order task. A 5-minute psychomotor vigilance task (PVT) was used as a behavioural measure of mental fatigue. Statistical analyses revealed a significant time by group interaction for PVT performance, such that the mental fatigue group demonstrated slower response times following the Stroop task. However, both groups demonstrated significantly faster response times and improved accuracy during the crossing order task following their respective intervention. The findings of this study suggest that the task was not cognitively demanding enough to reveal performance impairments associated with mental fatigue.

The hand grasp of an object is normally consistent, determined by the optimal, most efficient strategy learnt from previous experience. Yet in certain settings, despite object properties remaining constant and intention the same, the grasp chosen by an individual can vary with a lack of clear preference for a particular grasp configuration. This is referred to as motor ambiguity. Here, we compare the influence of preceding static versus dynamic visual information on participants' choice between two possible hand configurations when grasping an object at various orientations. We confirm previous findings that presentation of an object in an initial static orientation prior to the grasping in ambiguous orientation causes subjects to select a grasp that would be most congruent with the initial, determinate orientation. However, we unexpectedly found that when object rotation is observed between the initial and target positions, the bias is inversed, i.e. subjects choose the alternate grasp configurations. Furthermore, the inverse bias strength was found to be independent of the motion magnitude, and persists even when greater decision time is allowed. We discuss several possibilities across perceptual and decision making circuitry that might manifest this behavioural phenomenon.