Frontiers in Systems Neuroscience最新文献

As users transition from drivers to passengers in automated vehicles, they often take their eyes off the road to engage in non-driving activities. In driving simulators, visual motion is presented with scaled or without physical motion, leading to a mismatch between expected and perceived motion. Both conditions elicit motion sickness, calling for enhanced vehicle and simulator motion control strategies. Given the large differences in sickness susceptibility between individuals, effective countermeasures must address this at a personal level. This paper combines a group-averaged sensory conflict model with an individualized Accumulation Model (AM) to capture individual differences in motion sickness susceptibility across various conditions. The feasibility of this framework is verified using three datasets involving sickening conditions: (1) vehicle experiments with and without outside vision, (2) corresponding vehicle and driving simulator experiments, and (3) vehicle experiments with various non-driving-related tasks. All datasets involve passive motion, mirroring experience in automated vehicles. The preferred model (AM2) can fit individual motion sickness responses across conditions using only two individualized parameters (gain K ₁ and time constant T ₁) instead of the original five, ensuring unique parameters for each participant and generalisability across conditions. An average improvement factor of 1.7 in fitting individual motion sickness responses is achieved with the AM2 model compared to the group-averaged AM0 model. This framework demonstrates robustness by accurately modeling distinct motion and vision conditions. A Gaussian mixture model of the parameter distribution across a population is developed, which predicts motion sickness in an unseen dataset with an average RMSE of 0.47. This model reduces the need for large-scale population experiments, accelerating research and development.

Introduction: Children living with perinatally acquired HIV (CPHIV) demonstrate hearing impairments and language processing delays even in the presence of combination antiretroviral therapy (cART). Investigations on the effect of HIV on the auditory system have predominantly focused on the peripheral auditory system. Additionally, language processing requires the efficient interaction between central auditory system (CAS) brain regions and non-auditory regions. Investigating the functional connectivity (FC) within the CAS and between the CAS and non-auditory regions may reveal the influence of HIV on regions involved in auditory function.

Methods: Within a Bayesian statistical framework, we used resting-state functional magnetic resonance imaging to map FC in the CAS as well as between CAS regions and non-auditory regions of 11-year-old CPHIV. Graph theory was used to investigate the regional effects of HIV on brain network properties. We explored the relationships between FC and neurocognitive outcomes. We hypothesized that CPHIV would show disruptions in FC between CAS regions as well as between CAS and non-auditory regions. Secondly, we hypothesized that in CPHIV, regional brain network properties would be altered compared to their uninfected peers (CHUU). Finally we hypothesized that FC and functional network regional outcomes would be related to neurocognitive outcomes.

Results: Our investigation revealed lower FC of the primary auditory cortex (PAC) in CPHIV as well as disruptions in FC between CAS regions and non-auditory regions including hippocampal sub-regions, the lingual gyri and basal ganglia. Functional network analysis revealed lower nodal degree and efficiency in CAS regions including the cochlear nucleus/superior olivary complex and the inferior colliculus. We also report associations between the nodal efficiency of middle temporal and superior frontal regions and delayed recall, a neurocognitive marker of working memory, present in CHUU but not in CPHIV.

Discussion: Our results demonstrate FC alterations in the PAC and between CAS regions and non-auditory regions involved in limbic, visual and motor processing, as well as disruptions to the regional properties of the CAS regions in the functional brain network. These results provide insight into the state of the CAS FC in the presence of HIV and its possible role in the hearing and language impairments seen in this population.

Objective: To review and organize the research results on the mechanism of action of acupuncture in the treatment of subjective tinnitus over the past 30 years. This will provide a reference basis for the clinical acupuncture treatment of subjective tinnitus.

Methods: Computer searches of PubMed, China National Knowledge Infrastructure (CNKI), and China Science and Technology Journal Database (CCD) were conducted to collect and organize literature on the research on the mechanism of action of acupuncture in the treatment of subjective tinnitus. The searches were limited to the period from January 1, 1995 to July 31, 2024. The literature was then summarized and analyzed in terms of the blood circulation of the inner ear, immuno-inflammation, and neural cells to elaborate on the potential mechanism of action of acupuncture. The objective of this study was to describe the potential mechanism of action of acupuncture. The final results yielded 36 research papers related to subjective tinnitus and the mechanism of action of acupuncture. The identified mechanisms are as follows: the enhancement of local microcirculation in the inner ear by regulating the blood supply of the vertebrobasilar artery may improve the inner ear's blood supply obstacle. Additionally, the reduction of immuno-inflammatory factors in the inner ear may reduce the toxicity of the cochlea's hair cells and protect them. The modulation of 5-hydroxytryptamine receptors in the cochlear nucleus may serve to protect spiral ganglion neurons from damage. Additionally, the modulation of the thalamus and the functional reorganization of the auditory cortex and synaptic network may contribute to the achievement of therapeutic effects.

Conclusion: While acupuncture has demonstrated clinical efficacy in the treatment of subjective tinnitus, the underlying mechanism of action remains poorly understood. In the future, there is a need to accelerate the application of modern advanced technology and multidisciplinary cross-fertilization, as well as to conduct in-depth and systematic investigations into the mechanisms of acupuncture effects. This will provide an objective basis for clinical treatment.

Introduction: High-altitude environments challenge cognitive function due to hypoxia, yet their specific effects on cerebral lobe functions remain unclear. This study examines the impact of high-altitude exposure on frontal, parietal, temporal, and occipital lobes in climbers in the Nepali Himalayas, aiming to enhance understanding of altitude-related cognitive decline.

Methods: A cross-sectional cohort study was conducted with 76 participants, including 46 non-selected individuals (NOSCL) and 30 selected climbers divided into Everest (EMCL, n = 12), Kanchanjanga (KMCL, n = 9), and Manaslu (MMCL, n = 9) groups. Cognitive function tests (CFT) assessed cerebral lobe function at altitudes ranging from 800 to 5,500 meters using a non-invasive neuropsychological battery.

Results: Significant altitude-related declines were observed in frontal lobe function, particularly in the Visual Stroop test at 800 meters (75%, p < 0.001) and 2,700 meters (86.1%, p < 0.001). Attention scores also decreased at 800 meters (94.4%, p = 0.002). No significant changes were found in parietal, temporal, or occipital lobe functions. The Manaslu climb presented greater cognitive challenges than Everest or Kanchanjanga, with reduced attention and social cognition scores at 4,800 meters (p = 0.145).

Discussion: The findings indicate that frontal lobe functions are particularly vulnerable to hypoxia at high altitudes. The results support the necessity of region-specific cognitive testing for high-altitude risk assessments. Further research should explore long-term cognitive effects and mitigation strategies for climbers exposed to extreme altitude conditions.

Introduction: In neurodegenerative brain diseases like Progressive Supranuclear Palsy (PSP), clinical studies underscore the crucial role of head motion deficits. Similarly, advanced stage Idiopathic Parkinson's disease (IPD) is known to display significantly altered posture control and balance patterns involving the head segment.

Methods: This study investigates the relative differences in head control during a perturbed upright stance paradigm between patients affected by PSP and IPD, compared to healthy control subjects using dynamic system modeling. The resulting neural model underlines how PSP primarily affects head control, whereas IPD primarily affects the control of the whole body's center of mass. A neck control model, based on the hypothesis of modular posture control, is proposed to emulate the PSP data in particular.

Results: A larger passive stiffness was observed for both groups of patients, with eyes closed, suggesting that the head moves together with the trunk. With eyes open, the active proportional gain KP is relatively larger in all cases, indicating that the head is directed closer to the vertical by the visual contribution. Since this was held for all investigated groups, findings support the notion of intact visual contribution to posture control among PSP and IPD despite the impaired supranuclear eye guidance among PSP.

Discussion: The proposed neural model's characteristics will aid in future patient data analysis, disease progression monitoring, and possible modulation of disease-specific features through therapeutic intervention. For engineering and robotics implementations, uses for strengthened resilience of head stabilization are discussed.

It has been shown that the choice of preprocessing pipelines to remove contamination from functional magnetic resonance images can significantly impact the results, particularly in resting-state functional connectivity (rsFC) studies. This underscores the critical importance of replication studies with different preprocessing methodologies. In this study, we attempted to reproduce the rsFC results presented in an original study by Bauer et al. in 2017 on a group of sighted control (SC) and early blind (EB) subjects. By using the original dataset, we utilized another widely used software package to investigate how applying different implementations of the original pipeline (RMin model) or a more rigorous and extensive preprocessing stream (RExt model) can alter the whole-brain rsFC results. Our replication study was not able to fully reproduce the findings of the original paper. Overall, RExt shifted the distribution of rsFC values and reduced functional network density more drastically compared with RMin and the original pipeline. Remarkably, the largest rsFC effects appeared to primarily belong to certain connection pairs, irrespective of the pipeline used, likely demonstrating immunity of the larger effects and the true results against suboptimal processing. This may highlight the significance of results verification across different computational streams in pursuit of the true findings.

Hidden Markov Models (HMMs) have emerged as a powerful tool for analyzing time series of neural activity. Gaussian HMMs and their time-resolved extension, Time-Delay Embedded HMMs (TDE-HMMs), have been instrumental in detecting discrete brain states in the form of temporal sequences of large-scale brain networks. To assess the performance of Gaussian HMMs and TDE-HMMs in this context, we conducted simulations that generated synthetic data representing multiple phase-coupled interactions between different cortical regions to mimic real neural data. Our study demonstrates that TDE-HMM performs better than Gaussian HMM in accurately detecting brain states from synthetic phase-coupled interaction data. Finally, for TDE-HMMs, we manipulated key parameters such as phase coupling variability, state duration, and influence of volume conduction effect to evaluate the models' performance under varying conditions.

Here, Freeman Neurodynamics is explored to introduce the reader to the challenges of analyzing electrocorticogram or electroencephalogram signals to make sense of two things: (a) how the brain participates in the creation of knowledge and meaning and (b) how to differentiate between cognitive states or modalities in brain dynamics. The first (a) is addressed via a Hilbert transform-based methodology and the second (b) via a Fourier transform methodology. These methodologies, it seems to us, conform with the systems' neuroscience views, models, and signal analysis methods that Walter J. Freeman III used and left for us as his legacy.

[This corrects the article DOI: 10.3389/fnsys.2022.920703.].