Brain Structure & Function最新文献

The present correspondence constitutes a response to the Letter to the Editor regarding our publication Sex Differences in Neuropathological Response to Traumatic Brain Injury: Increased Neuronal Loss and Astrogliosis in Females. We are pleased that our paper has attracted attention and hereby provide comments on the authors' observations and suggestions. In this reply, we clarify our rationale for analysing the cerebral cortex, the absence of behavioural data, and the choice of the 30-day post-injury timeframe, which was based on prior experience with this model of brain injury. Furthermore, we include information on the evaluation of the oestrous cycle as well as details of the image processing applied during the morphological analysis of glial cells. Finally, we outline our plans to broaden the scope of the study through the investigation of an alternative therapeutic approach to traumatic brain injury, incorporating multiple in vitro and in vivo methodologies, including histological, biochemical, and imaging techniques.

To investigate the potential bidirectional causal relationships between resting-state functional brain activity and major kidney diseases. We accessed genome-wide association study (GWAS) summary data of 191 resting-state fMRI (rs-fMRI) phenotypes. Summary-level GWAS data for seven kidney diseases-diabetic nephropathy, chronic kidney disease, glomerulonephritis, nephrotic syndrome, cystic kidney disease, IgA nephropathy, and kidney cyst-were obtained from the FinnGen consortium or the Kiryluk Lab, all based on European ancestry (sample sizes ranging up to 11,265 cases and 436,208 controls). We employed inverse variance weighted (IVW) analysis as the primary MR approach, supplemented by MR-Egger, Weighted Median, Weighted Mode, and Robust Adjusted Profile Score (RAPS) to evaluate pleiotropy and heterogeneity. Forward MR demonstrated that certain brain networks, such as the central executive network, default mode network, limbic network, and other interconnected circuits, appear to influence susceptibility to various kidney diseases. Reverse MR indicated that disrupted kidney function, particularly CKD, may adversely affect key brain functional networks, including those responsible for sensory-motor processing and cognitive integration. Although the observed effect sizes were modest, our results provide evidence that kidney diseases and brain functional activity may be interlinked, aligning with clinical observations of neurological-urinary system correlations and emerging data on cortical structural changes in chronic kidney disease. The "kidney-brain axis" could be relevant to both renal and neurological pathophysiology.

Inhibition represents a core executive function which underlies the ability to suppress interfering or distracting stimuli, thereby building resistance against task-irrelevant information. However, the impact of ageing on inhibitory functioning and the role of neuroplasticity - largely driven by predominant excitatory (glutamatergic) and inhibitory (GABAergic) neurochemicals - remains poorly understood. This study investigated age relationships with neurochemical concentrations (GABA + and Glx) and their associations with inhibitory sub-components in healthy ageing. Participants completed three inhibition tasks (flanker, Stroop, go/no-go), each measuring a different sub-component process, via the PsyToolkit platform. MRS data were acquired in the sensorimotor (SM1; n = 71, mean age (SD) = 68.3 (± 9.7) years, 39 females) and prefrontal (PFC; n = 58, mean age (SD) = 67.6 (± 9.6) years, 30 females) regions using a HERMES sequence and analysed using OSPREY's pipeline. After correcting for gender and education, semi-partial correlations revealed no significant relationships between age and GABA + or Glx concentrations in either the SM1 or PFC. Furthermore, after correcting for age, gender and education, partial correlations identified a significant negative relationship between SM1 Glx concentrations and go/no-go error rates, such that greater concentrations of SM1 Glx were associated with greater go/no-go accuracy. The null age-neurochemical results suggest that GABA + and Glx may not uniformly decline during healthy ageing, indicating a more nuanced relationship than previously reported. In addition, our neurochemical-behavioural findings provide neurochemically-and-spatially specific evidence that SM1 Glx concentrations may be important for response inhibition. This result indicates a role for the glutamatergic system in supporting inhibition, independent of age.

Traditional brain connectivity studies have focused mainly on structural connectivity, often relying on tractography with diffusion MRI (dMRI) to reconstruct white matter pathways. In parallel, studies of functional connectivity have examined correlations in brain activity using fMRI. However, emerging methodologies are advancing our understanding of brain networks. Here we explore advanced connectivity approaches beyond conventional tractography, focusing on dMRI morphometry and the integration of structural and functional connectivity analysis. dMRI morphometry enables quantitative assessment of white matter pathway volumes through statistical comparison with normative populations, while functional connectivity reveals network organization that is not restricted to direct anatomical connections. More recently, approaches that combine diffusion tensor imaging (DTI) with functional correlation tensor (FCT) analysis have been introduced, and these complementary methods provide new perspectives into brain structure-function relationships. Together, such approaches have important implications for neurodevelopmental and neurological disorders as well as brain plasticity. The integration of these methods with artificial intelligence techniques have the potential to support both basic neuroscience research and clinical applications.

Diffusion magnetic resonance imaging (dMRI) is a non-invasive neuroimaging technique that measures the displacement of water molecules in tissue over time. Due to its sensitivity to micron-scale water movement, which is influenced by cellular structures like membranes, axons, and myelin, dMRI is a unique method for probing tissue microstructure. Among dMRI analysis approaches, neurite orientation dispersion and density imaging (NODDI) is a biophysical modeling technique that enables the characterization of cytoarchitectural and myeloarchitectural features in the brain. The early postnatal period is characterized by rapid and dynamic biological processes such as axonal growth, dendritic arborization, and synaptogenesis-changes that alter the microstructural environment in ways that are detectable by NODDI. Thus, NODDI presents a promising approach for characterizing early brain development, offering biologically specific markers of tissue organization that are responsive to these maturational events. This review presents emerging literature on NODDI applications during early infancy, demonstrating its utility in mapping normative developmental trajectories, investigating alterations in preterm populations, and linking microstructural properties to environmental influences and emerging behavioral outcomes. While current literature offers initial insights into early microstructural development patterns, NODDI applications in infancy remain limited, and existing studies are constrained by small sample sizes, limited age coverage, and lack of longitudinal data. Nonetheless, initial evidence suggests that NODDI can complement conventional diffusion metrics and may provide novel insights into early neural maturation and plasticity. Continued application and methodological refinement of NODDI in infancy may help delineate sensitive periods of brain development and improve the interpretation of emerging neurobehavioral phenotypes.

As the population of older adults grows, so does the prevalence of neurocognitive disorders such as mild cognitive impairment (MCI) and dementia. While biochemical, genetic, and neuroimaging biomarkers have accelerated early detection and diagnosis, neurophysiological measures are absent from daily medical use. Electroencephalography (EEG) and magnetoencephalography (MEG) are two non-invasive techniques that measure neurophysiological signals in the brain and convey information about signal strength at different frequency bands, event-related activity, signal complexity, and temporal correlation between spatially remote brain regions. Here we conducted a pre-registered, comprehensive systematic review of 942 studies using EEG, MEG, and combined MEG and EEG to characterise the neurophysiology of healthy aging, MCI, and dementia under resting-state and task conditions. To complement our search, we also reviewed 51 past reviews in the field. Relevant features of these papers were extracted to present a detailed overview of the current state of evidence. Overall, neurophysiological measures show potential as diagnostic tools and could prove very valuable in predicting healthy and pathological aging trajectories. However, to reach this goal in clinical practice, it is crucial to adopt longitudinal designs, standardise methodologies, and identify biomarkers at the individual rather than group level.

Shift work can lead to mental health issues such as sleep disturbances and cognitive impairment. Neural activation in response to external sleep-related stimuli may vary according to shift work patterns. In this study, we investigated the differences in brain activity in response to sleep-related stimuli between shift-worker (SW) nurses and healthy controls (HCs), and we also assessed the relationships between sleep-related problems and brain activity. The hypothesis was that shift workers would exhibit altered activation in the prefrontal cortex (PFC) when processing sleep-related stimuli, reflecting attentional biases associated with sleep disturbances.Participants completed a cognitive task during functional magnetic resonance imaging that involved viewing sleep-related and neutral pictures. Subjective sleep was assessed using self-reported questionnaires and a 1-week sleep diary. Objective sleep parameters, along with the 24-h rest-activity rhythm, were evaluated via actigraphy conducted over 1 week. We analyzed group differences in the neural processing of sleep-related stimuli and conducted correlation analyses to explore the associations between brain activity and sleep parameters.This study included 44 SWs and 37 HCs. Compared to HCs, SWs demonstrated significantly lower activity in the dorsomedial prefrontal cortex (DMPFC) and lateral prefrontal cortex (LPFC) in response to sleep-related pictures than neutral pictures. DMPFC activity was significantly negatively correlated with subjective sleep problems (e.g., self-reported insomnia and fatigue), whereas LPFC activity was strongly correlated with actigraphy-measured 24-h rest-activity rhythm parameters (e.g., a robust 24-h rhythm).The decreased activation of the prefrontal cortex in response to sleep-related stimuli in SWs may reflect diminished attentional control over sleep and increased rumination on intrusive sleep-related thoughts. These findings enhance our understanding of the neurobiological mechanisms underlying sleep-related issues in SWs and may inform interventions to mitigate mental health problems in this population.

The anterior commissure (AC) has an anterior and posterior limb. Despite comprehensive information about the posterior limb, there is limited and conflicting information about the anterior limb in the literature. We aimed to show the anatomical relationships of the AC with neighboring structures by using white matter microdissection and magnetic resonance (MR) tractography, primarily on the anterior limb of the AC. Twenty cadaveric human brains and three sheep brains were prepared according to Klingler's method. White matter fiber microdissections were performed. MR tractography was done in 20 specimens. This study defined the body and anterior and posterior limbs of the AC. The anterior limb leaves the body from the inferior side at the level of the anterior perforated substance and olfactory tract. It then courses anteroinferolaterally, curves towards the orbital gyri, and terminates at the olfactory trigone. The posterior limb of the AC divides into rostral (anterolateral) and caudal (posterolateral) parts. The anterior limb was more prominent in sheep than in human brains. This study accurately delineates the anatomy and variations of the anterior limb of the AC in human and sheep brains for the first time in the literature to the best of our knowledge. The anterior limb of the AC is larger in sheep than in humans. An increased importance of olfaction could be the evolutionary explanation for this difference. The MR tractography results shown are unique for this delicate anatomy.