Frontiers in Neuroscience最新文献

Introduction: Immune reconstitution therapies (IRT) are highly effective therapies for multiple sclerosis (MS). Among IRT, we can distinguish partially selective therapies such as cladribine in tablets (CLAD) and non-selective therapies, which include alemtuzumab (ALEM). Today, it is known that these therapies are effective in controlling the relapse activity of the disease and the progression of clinical disability, which has been proven both in clinical trials and in real world evidence (RWE). However, there is a lack of data assessing the effect of IRT on the neurodegenerative process, which is intensified in patients with MS. The aim of the study was to assess the effect of IRT treatment on the degree and pattern of brain atrophy in patients with MS during 3 years of observation.

Methods: Patients with relapsing-remitting MS (RRMS) treated with CLAD and ALEM were retrospectively recruited for the study. Demographic, clinical, and magnetic resonance imaging (MRI) data were collected at 4 time points: before the treatment and one, two, and three years after the treatment. MRI examinations were analyzed volumetrically using Freesurfer software. Global and regional changes in atrophy were assessed by calculating percentage changes in volume between time points. Results of drug groups were compared with each other.

Results: After 3 years of follow-up, statistically significant differences between groups were observed in hippocampus [p < 0.01] and amygdala volume changes [p < 0.01]. Ventral diencephalon atrophy was noted in both groups. On the other hand, in both groups, no significant atrophy of white and grey matter was noted. In addition, an increase in the thalamus volume was observed.

Discussion: In the studied groups, IRT therapies were shown to slow down the atrophy process in MS patients to a similar extent. These therapies may play a neuroprotective role by increasing the volume of the thalamus and hippocampus. The study was limited by the small number of both groups. Therefore, further studies are needed to fully assess the effect of reconstitution therapies on neurodegenerative processes in patients with RRMS.

Objective: Wireless electrocorticography (ECoG) recording from unrestrained nonhuman primates during behavioral tasks is a potent method for investigating higher-order brain functions over extended periods. However, conventional wireless neural recording devices have not been optimized for ECoG recording, and few devices have been tested on freely moving primates engaged in behavioral tasks within their home cages.

Methods: We developed a compact, low-power, 32-channel wireless ECoG headstage specifically designed for neuroscience research. To evaluate its efficacy, we established a behavioral task setup within a home cage environment.

Results: The developed headstage weighed merely 1.8 g and had compact dimensions of 25 mm × 16 mm × 4 mm. It was efficiently powered by a 100-mAh battery (weighing 3 g), enabling continuous recording for 8.5 h. The device successfully recorded data from an unrestrained monkey performing a center-out joystick task within its home cage.

Conclusion: The device demonstrated excellent capability for recording ECoG data from freely moving primates in a home cage environment. This versatile device enhances task design freedom, decrease researchers' workload, and enhances data collection efficiency.

Background: Tinnitus persists as a significant public health challenge with elusive neurochemical underpinnings. Emerging evidence implicates dysregulated excitatory-inhibitory neurotransmission in the anterior cingulate cortex (ACC), a limbic-auditory hub governing tinnitus salience. This study investigates dynamic ACC neurochemical changes during tinnitus progression.

Methods: Using single-voxel magnetic resonance spectroscopy (MRS), GABA+/creatine (Cr) and Glx (glutamate+glutamine)/Cr ratios were measured in the ACC of 16 recent-onset (RO; <6 months), 22 chronic (CH; ≥6 months) tinnitus patients, and 26 healthy controls (HC). Tinnitus severity was assessed via tinnitometry and Tinnitus Functional Index (TFI).

Results: RO patients exhibited significantly reduced ACC GABA+/Cr compared to CH and HC groups (p < 0.05), while CH and HC showed no differences. GABA+/Cr positively correlated with tinnitus duration across patients (r = 0.364, p = 0.025). Although Glx/Cr did not differ between groups, elevated Glx/Cr associated with higher tinnitus pitch-matching frequencies (r = 0.421, p = 0.008) and emotional distress (TFI-E; r = 0.370, p = 0.022), though these findings did not survive multiple comparison correction.

Conclusion: Early tinnitus is characterized by ACC GABAergic deficits, while chronicity features normalized GABA+/Cr levels-suggesting compensatory neuroplastic restoration of inhibition over time. Glutamatergic activity may modulate perceptual and emotional dimensions of tinnitus. These phase-specific ACC neurochemical shifts highlight potential therapeutic targets for arresting tinnitus progression. Longitudinal studies are warranted to validate temporal dynamics.

Introduction: The prevalence of female-to-male (FtM) transgender individuals has risen recently, yet the effects of cross-sex hormone therapy on volumetric differences in the hippocampal subfields remain poorly understood. This study aimed to evaluate the differences of gray matter (GM) volume, especially focusing on the hippocampal subfields, in FtM transgender individuals and premenopausal cisgender women.

Methods: Seventeen FtM transgender individuals who had undergone hysterectomies and were receiving testosterone therapy before participating in this study, along with 20 premenopausal women, underwent a single session of T1-weighted magnetic resonance imaging (MRI).

Results: FtM transgender group had significantly higher free-testosterone (free-T) levels and lower estradiol levels compared with premenopausal women group (p < 0.001). In voxel-wise analysis, FtM transgender individuals showed significantly larger GM volumes in the caudate nucleus, hypothalamus, and thalamus compared with premenopausal women (p < 0.01, FWE-corrected). More specifically, the right hippocampal subiculum volume was larger in FtM transgender individuals (p < 0.05, Bonferroni-corrected), and these volumes were positively correlated with the free-T levels (r = 0.34, p = 0.04). This study revealed the specific hippocampal subfield volume differences in the testosterone-treated FtM transgender group when compared to cisgender premenopausal women group.

Discussion: These findings might help elucidate the morphological variation of the specific cerebral regions associated with testosterone therapy in FtM transgender individuals and contribute to our understanding of the effects of gender-affirming hormone treatments as well.

Background: Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a prevalent condition in urology characterized by chronic pain. The pathogenesis of CP/CPPS remains unclear.

Methods: We enrolled 45 eligible CP/CPPS patients and 45 healthy volunteers. We evaluated their resting-state fMRI data using a comprehensive set of parameters, such as Regional Homogeneity (ReHo) and Degree Centrality (DC), to detect brain abnormalities and identify potential correlates with the clinical manifestations of CP/CPPS. We further categorized the patients into subgroups according to their scores of NIH-CPSI to elucidate the brain changes associated with differing symptom severities.

Results: Profound alterations in brain function were observed in patients with CP/CPPS. These changes involved multiple brain regions identified by DC analysis, including the right anterior cingulate cortex (ACC), left inferior frontal opercular cortex, left amygdala, right middle frontal cortex, and bilateral insula. ReHo analysis revealed significant changes in the right thalamus, left inferior frontal triangular cortex, right superior temporal pole, left ACC, and right superior frontal cortex (cluster >20 voxels, GRF correction, p < 0.05). Analysis using ReHo and DC revealed that brain alterations associated with varying symptom severities were localized in pain perception and modulation regions. Specifically, the DC values in the right ACC showed a linear correlation with the severity of symptoms measured by the NIH-CPSI (AUC = 0.9654, p < 0.0001).

Conclusion: In CP/CPPS, we first discovered differences in brain function among patients with varying degrees of severity. The brain alterations of DC in the right ACC might be a potential biomarker for diagnosing and assessing disease severity.

Introduction: Cochlear implant (CI) success is often assessed using subjective tests like word recognition scores (WRS). However, these tests are unsuitable for children, non-native speakers, and individuals with cognitive impairments. Mismatch negativity (MMN), an objective measure of cortical auditory processing, offers a promising alternative for evaluating speech perception. This study aimed to assess speech perception in CI patients using MMN and examine its correlation with WRS.

Methods: The study included 23 ears from CI users fitted for at least six months. Speech stimuli were presented via direct audio input to the CI processor at 70 dB nHL using an MMN paradigm. The syllables 'ba' (standard) and 'da' (deviant) served as stimuli. MMN amplitude and latency were analyzed, and their correlation with WRS was examined.

Results: A significant correlation was observed between WRS and MMN responses. CI users with lower WRS scores exhibited reduced MMN amplitudes and prolonged latencies compared to those with higher scores, indicating impaired cortical speech processing.

Discussion: These findings suggest that speech-induced MMN could serve as an objective tool for assessing speech perception in CI users. MMN provides valuable insights for optimizing CI fitting, particularly for patients unable to undergo subjective testing. Integrating MMN into clinical practice could improve speech perception outcomes and enhance the quality of life for CI users.

Introduction: In aviation, exceptional visual perception is crucial for pilots to monitor flight instruments and respond swiftly to deviations, as well as make rapid judgments regarding environmental changes, ensuring aviation safety. However, existing research on pilots' visual perception has predominantly focused on behavioral observations, with limited exploration of the neurophysiological mechanisms involved.

Methods: This study aimed to investigate the brain activity associated with the visual perception capabilities of flight cadets. Data were collected from 25 flying cadets and 24 ground students under two conditions: a resting-state functional magnetic resonance imaging session conducted in 2022 and a change-detection task. The data were analyzed using RESTplus software.

Results: The analysis revealed that degree centrality values in the right precuneus and left lingual gyrus showed significantly positive correlations with task reaction time and accuracy, respectively, in the pilot group. These brain regions were found to be significantly associated with the visual perception abilities of the pilots.

Discussion: The findings suggest that alterations in the left precuneus and right lingual gyrus in pilots are linked to their visual perception capabilities, which may play a crucial role in mission performance. These results provide a foundation for improving flight training programs and selecting suitable flight trainees based on neurophysiological markers of visual perception.

Introduction: A full understanding of how we see our world remains a fundamental research question in vision neuroscience. While topographic profiling has allowed us to identify different visual areas, the exact functional characteristics and organization of areas up in the visual hierarchy (beyond V1 & V2) is still debated. It is hypothesized that visual area V4 represents a vital intermediate stage of processing spatial and curvature information preceding object recognition. Advancements in magnetic resonance imaging hardware and acquisition techniques (e.g., non-BOLD functional MRI) now permits the capture of cortical layer-specific functional properties and organization of the human brain (including the visual system) at high precision.

Methods: Here, we use functional cerebral blood volume measures to study the modularity in how responses to contours (curvature) are organized within area V4 of the human brain. To achieve this at 3 Tesla (a clinically relevant field strength) we utilize optimized high-resolution 3D-Echo Planar Imaging (EPI) Vascular Space Occupancy (VASO) measurements.

Results: Data here provide the first evidence of curvature domains in human V4 that are consistent with previous findings from non-human primates. We show that VASO and BOLD tSNR maps for functional imaging align with high field equivalents, with robust time series of changes to visual stimuli measured across the visual cortex. V4 curvature preference maps for VASO show strong modular organization compared to BOLD imaging contrast. It is noted that BOLD has a much lower sensitivity (due to known venous vasculature weightings) and specificity to stimulus contrast. We show evidence that curvature domains persist across the cortical depth. The work advances our understanding of the role of mid-level area V4 in human processing of curvature and shape features.

Impact: Knowledge of how the functional architecture and hierarchical integration of local contours (curvature) contribute to formation of shapes can inform computational models of object recognition. Techniques described here allow for quantification of individual differences in functional architecture of mid-level visual areas to help drive a better understanding of how changes in functional brain organization relate to difference in visual perception.

Chronic stress can impact brain function through various mechanisms, contributing to the development of anxiety disorders. Chronic unpredictable mild stress (CUMS) is a well-established model for studying the effects of chronic stress. This study assessed the impacts of different durations of CUMS on anxiety-like behavior, inflammation, and tryptophan metabolism in female C57BL/6N mice. The results revealed significant behavioral changes after 2-4 weeks of CUMS. Specifically, the open arms ratio and open arms time ratio in the elevated plus maze (EPM) decreased, the latency to feed in the novelty-suppressed feeding test (NSFT) was prolonged, and the number of transitions in the light/dark box (LDB) was decreased. After 1 week of CUMS, the levels of some pro-inflammatory cytokines (such as IL-1β and iNOS) and anti-inflammatory cytokines (including IL-10) began to rise. After 2 weeks of CUMS, most pro-inflammatory cytokines (IL-1β, IL-6, CD86, iNOS) and the anti-inflammatory cytokines TGF-β and CD11b showed an increase, while some anti-inflammatory cytokines (Arg-1, IL-10) began to decrease. After 3 weeks of stress, the pro-inflammatory cytokine TNF-α also significantly increased, while the anti-inflammatory cytokine TGF-β began to decline. By 4 weeks of CUMS, the anti-inflammatory cytokine CD11b also started to decrease. Regarding tryptophan metabolism, after 3-4 weeks of CUMS, serotonin (5-HT) levels in the hippocampus of the mice began to decrease. Additionally, the kynurenine pathway in tryptophan metabolism shifted more towards the KYN-QA branch, resulting in the reduction in the neuroprotective substance kynurenic acid (KYNA), while neurotoxic substances such as 3-hydroxykynurenine (3-HK) and quinolinic acid (QA) accumulated. In summary, female C57BL/6N mice exhibit anxiety-like behavior after 2 weeks of CUMS, accompanied by inflammatory responses. After 3-4 weeks of CUMS, anxiety-like behavior persists, with exacerbated inflammatory responses and disturbances in tryptophan metabolism.

Introduction: Mild cognitive impairment (MCI), often linked to early neurodegeneration, is associated with subtle disruptions in brain connectivity. In this paper, the applicability of persistent homology, a cutting-edge topological data analysis technique is explored for classifying MCI subtypes.

Method: The study examines brain network topology derived from fMRI time series data. In this regard, we investigate two methods for computing persistent homology: (1) Vietoris-Rips filtration, which leverages point clouds generated from fMRI time series to capture dynamic and global changes in brain connectivity, and (2) graph filtration, which examines connectivity matrices based on static pairwise correlations. The obtained persistent topological features are quantified using Wasserstein distance, which enables a detailed comparison of brain network structures.

Result: Our findings show that Vietoris-Rips filtration significantly outperforms graph filtration in brain network analysis. Specifically, it achieves a maximum accuracy of 85.7% in the Default Mode Network, for classifying MCI using in-house dataset.

Discussion: This study highlights the superior ability of Vietoris-Rips filtration to capture intricate brain network patterns, offering a robust tool for early diagnosis and precise classification of MCI subtypes.