Brain Aging Process Research Articles

Static and dynamic connectivity structure of white-matter functional networks across the adult lifespan.

Aging of the human brain involves intricate biological processes, resulting in complex changes in structure and function. While the effects of aging on gray matter (GM) connectivity are extensively studied, white matter (WM) functional changes have received comparatively less attention. This study examines age-related WM functional dynamics using resting-state fMRI across the adult lifespan. We identified GM and WM functional networks (FNs) using k-means clustering. Static and dynamic analyses of WM functional network connectivity (FNC) were performed to explore age effects on WM-FNs and recurrent patterns of dynamic FNC. We identified 9 WM and 12 GM FNs. Age-related effects on WM FNC strength and WM-GM FNC dynamics included linear positive and U-shaped age trajectories in static FNC strength, and linear negative and inverted U-shaped trajectories in FNC temporal variability. Three distinct brain states with significant age-related differences were identified and validated. These findings were largely replicated in the validation analysis. High integration and low temporal variability in WM-GM FNC may indicate reduced adaptability of the network system in older adults, offering insights into brain aging processes.

Cognitive and Alzheimer's disease biomarker effects of oral nicotinamide riboside (NR) supplementation in older adults with subjective cognitive decline and mild cognitive impairment.

Age-associated depletion in nicotinamide adenine dinucleotide (NAD+) concentrations has been implicated in metabolic, cardiovascular, and neurodegenerative disorders. Supplementation with NAD+ precursors, such as nicotinamide riboside (NR), offers a potential therapeutic avenue against neurodegenerative pathologies in aging, Alzheimer's disease, and related dementias. A crossover, double-blind, randomized placebo (PBO) controlled trial was conducted to test the safety and efficacy of 8 weeks' active treatment with NR (1 g/day) on cognition and plasma AD biomarkers in older adults with subjective cognitive decline and mild cognitive impairment. The primary efficacy outcome was the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Secondary outcomes included plasma phosphorylated tau 217 (pTau217), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL). Exploratory outcomes included Lumosity gameplay (z-scores) for cognition and step counts from wearables. Mixed model for repeated measures was used for between-group comparisons; paired t-tests were used for within-individual comparisons. Forty-six participants aged over 55 were randomized to NR-PBO or PBO-NR groups; 41 completed baseline visits, and 37 completed the trial. NR supplementation was safe and well tolerated with no differences in adverse events reported between NR and PBO treatment phases. For the between-group comparison, there was a 7% reduction in pTau217 concentrations after taking NR, while an 18% increase with PBO (p = 0.02). No significant between-group differences were observed for RBANS, other plasma biomarkers(GFAP and NfL), Lumosity gameplay scores or step counts. For the within-individual comparison, pTau217 concentrations significantly decreased during the NR phase compared to the PBO (p = 0.02), while step counts significantly increased during the NR phase than PBO (p = 0.04). Eight weeks NR supplementation is safe and lowered pTau217 concentrations but did not alter cognition as measured by conventional or novel digital assessments. Further research is warranted to validate NR's efficacy in altering pathological brain aging processes. The integrated study design combines a two-arm parallel trial with a crossover phase, offering the opportunity to enhance sample size for within-individual analysis and assess carryover effects.NR is safe but did not alter cognition as measured by multi-modal assessments in SCD/MCI.For between-group comparison, pTau217 levels decreased with NR and increased with PBO at 8-week follow-up.For within-individual comparison, step counts increased after NR and decreased after PBO.A larger, longer study with pharmacodynamic and pathophysiological biomarkers is needed to assess NR's disease-modifying effects.

Statin use is associated with higher white matter hyperintensity volumes and lower grey matter volumes.

While statins are routinely prescribed to prevent cardiovascular diseases, their effects on brain alterations remain largely unknown. Very few studies have examined the differences in brain volumes between statin users and non-users, and existing research has yielded inconsistent results. This cross-sectional study aims to investigate the association between statin use at baseline and global and specific brain volumes measured 9 years later in a large population-based sample of middle-aged and older adults. Participants from the UK Biobank without neurological and psychiatric disorders consisted of 3285 statin users (mean 60 years and 69% males) and 36 229 non-users (mean 55 years and 46% males). We used linear models to estimate the mean volumetric differences between statin users and non-users while adjusting for UK Biobank assessment centre, age, sex, ethnicity, education, apolipoprotein E ɛ4 status, Townsend deprivation index, antidepressant use, intracranial volume, lifestyle factors (alcohol intake frequency, smoking and physical activity) and health-related conditions (body mass index, blood pressure, diabetes, coronary heart disease, stroke, head injury, depression and insomnia). Moreover, mediation analysis was performed to evaluate whether the association between statin use and global brain volumes was mediated by total serum cholesterol concentration. Statin use was associated with lower grey matter volume [β = -1575 mm3 (-2358, -791)], with 20% of this association mediated by total serum cholesterol concentration. Statin use was also associated with lower peripheral cortical grey matter volumes [β = -1448 mm3 (-2227, -668)] and higher white matter hyperintensity [β = 0.11 mm3 (0.07, 0.15)]. However, white matter volume did not differ significantly between statin users and non-users. Further analyses revealed that volumes of thalamus, pallidum, hippocampus, nucleus accumbens and other regions of the temporal lobe were smaller among statin users compared with non-users. This study showed that statin use is associated with higher white matter hyperintensity volumes and lower total and peripheral cortical grey matter volumes 9 years later, indicative of the brain's ageing process. Moreover, the observed grey matter alterations were partially explained by statin-induced total serum cholesterol reduction. This study emphasizes the potential direct and indirect effects of statins on brain volume.

Acceleration of brain aging after small-volume infarcts.

Previous studies have shown that stroke patients exhibit greater neuroimaging-derived biological "brain age" than control subjects. This difference, known as the brain age gap (BAG), is calculated by comparing the chronological age with predicted brain age and is used as an indicator of brain health and aging. However, whether stroke accelerates the process of brain aging in patients with small-volume infarcts has not been established. By utilizing longitudinal data, we aimed to investigate whether small-volume infarctions can significantly increase the BAG, indicating accelerated brain aging. A total of 123 stroke patients presenting with small-volume infarcts were included in this retrospective study. The brain age model was trained via established protocols within the field of machine learning and the structural features of the brain from our previous study. We used t-tests and regression analyses to assess longitudinal brain age changes after stroke and the associations between brain age, acute stroke severity, and poststroke outcome factors. Significant brain aging occurred between the initial and 6-month follow-ups, with a mean increase in brain age of 1.04 years (t = 3.066, p < 0.05). Patients under 50 years of age experienced less aging after stroke than those over 50 years of age (p = 0.245). Additionally, patients with a National Institute of Health Stroke Scale score >3 at admission presented more pronounced adverse effects on brain aging, even after adjusting for confounders such as chronological age, sex, and total intracranial volume (F 1,117 = 7.339, p = 0.008, η 2 = 0.059). There were significant differences in the proportional brain age difference at 6 months among the different functional outcome groups defined by the Barthel Index (F 2,118 = 4.637, p = 0.012, η 2 = 0.073). Stroke accelerates the brain aging process, even in patients with relatively small-volume infarcts. This phenomenon is particularly accentuated in elderly patients, and both stroke severity and poststroke functional outcomes are closely associated with accelerated brain aging. Further studies are needed to explore the mechanisms underlying the accelerated brain aging observed in stroke patients, with a particular focus on the structural alterations and plasticity of the brain following minor strokes.

Zuogui Pills Improve the Learning and Memory Ability of Brain-Aging Mice through the Estrogen Receptor ERα Methylation Pathway.

Sex hormones are important factors in maintaining brain function and acting as brain protectors. Recent research suggests that neuronal damage in brain aging may be linked to the methylation of the estrogen receptor α (ERα). However, the mechanism of Zuogui Pills (ZGW) in brain-aging ERα DNA methylation and neuronal repair remains unknown. D-galactose-induced ovary removal mice were used as a model of aging. Changes in estrous cycle were detected in mice by vaginal cell smear. Animal behavior tests, including the Morris water maze (MWM) and new object recognition (NOR) test, were conducted. Hematoxylin-eosin (HE) and Nissl-staining were carried out to assess hippocampal neurogenesis. Enzyme-linked immunosorbent assay (ELISA) was performed for 5- methylcytosine methylation levels, and immunohistochemistry (IHC) and western blotting (WB) experiments were performed to assess ERα/DNA methyltransferase 1 (DNMT1) expression after ZGW treatment. Finally, bisulfite sequencing PCR (BSP) analysis was performed to identify methylated differentially expressed estrogen receptor 1 (ESR1) gene in D-gal-induced senescent neurons before and after ZGW treatment. We found that ERα methylation was involved in the delayed brain ageing process of ZGW. Mechanistically, ZGW can improve the learning and memory ability of brain-aging mice, reduce the expression of 5-methylcytosine (5-mc) in serum, increase the amount of ERα, inhibit the expression of DNMT1, and significantly reduce methylated expression of the ESRI gene. Our data suggested that ZGW slowed down D-gal-induced brain aging in mice, and these results showed that ZGW is beneficial for aging. It may be used for neuronal protection in aging.

Brain aging patterns in a large and diverse cohort of 49,482 individuals.

Brain aging process is influenced by various lifestyle, environmental and genetic factors, as well as by age-related and often coexisting pathologies. Magnetic resonance imaging and artificial intelligence methods have been instrumental in understanding neuroanatomical changes that occur during aging. Large, diverse population studies enable identifying comprehensive and representative brain change patterns resulting from distinct but overlapping pathological and biological factors, revealing intersections and heterogeneity in affected brain regions and clinical phenotypes. Herein, we leverage a state-of-the-art deep-representation learning method, Surreal-GAN, and present methodological advances and extensive experimental results elucidating brain aging heterogeneity in a cohort of 49,482 individuals from 11 studies. Five dominant patterns of brain atrophy were identified and quantified for each individual by respective measures, R-indices. Their associations with biomedical, lifestyle and genetic factors provide insights into the etiology of observed variances, suggesting their potential as brain endophenotypes for genetic and lifestyle risks. Furthermore, baseline R-indices predict disease progression and mortality, capturing early changes as supplementary prognostic markers. These R-indices establish a dimensional approach to measuring aging trajectories and related brain changes. They hold promise for precise diagnostics, especially at preclinical stages, facilitating personalized patient management and targeted clinical trial recruitment based on specific brain endophenotypic expression and prognosis.

A perspective on epigenomic aging processes in the human brain and their plasticity in patients with mental disorders – a systematic review

The debate surrounding nature versus nurture remains a central question in neuroscience, psychology, and in psychiatry, holding implications for both aging processes and the etiology of mental illness. Epigenetics can serve as a bridge between genetic predisposition and environmental influences, thus offering a potential avenue for addressing these questions. Epigenetic clocks, in particular, offer a theoretical framework for measuring biological age based on DNA methylation signatures, enabling the identification of disparities between biological and chronological age. This structured review seeks to consolidate current knowledge regarding the relationship between mental disorders and epigenetic age within the brain. Through a comprehensive literature search encompassing databases such as EBSCO, PubMed, and ClinicalTrials.gov, relevant studies were identified and analyzed. Studies that met inclusion criteria were scrutinized, focusing on those with large sample sizes, analyses of both brain tissue and blood samples, investigation of frontal cortex markers, and a specific emphasis on schizophrenia and depressive disorders. Our review revealed a paucity of significant findings, yet notable insights emerged from studies meeting specific criteria. Studies characterized by extensive sample sizes, analysis of brain tissue and blood samples, assessment of frontal cortex markers, and a focus on schizophrenia and depressive disorders yielded particularly noteworthy results. Despite the limited number of significant findings, these studies shed light on the complex interplay between epigenetic aging and mental illness. While the current body of literature on epigenetic aging in mental disorders presents limited significant findings, it underscores the importance of further research in this area. Future studies should prioritize large sample sizes, comprehensive analyses of brain tissue and blood samples, exploration of specific brain regions such as the frontal cortex, and a focus on key mental disorders. Such endeavors will contribute to a deeper understanding of the relationship between epigenetic aging and mental illness, potentially informing novel diagnostic and therapeutic approaches.

Exploring Neuroprotective Botanical Remedies in Neurodegenerative Conditions: A Review

Neuroprotection refers to the mechanisms and strategies used to protect the Central Nervous System (CNS) from neuronal injuries caused by neurodegenerative disorders. Neurodegenerative disorders are a type of chronic condition in which parts of the nervous system deteriorate over time, most notably the brain. These disorders have a slow and gradual effect on an individual. Neurodegeneration is a neuropathological condition and brain aging process. The brain pathology of neurodegenerative and cerebrovascular disease is a leading cause of death worldwide, with a death rate of approximately 8% and an incidence rate of approximately 2/1000. It is a major health issue in the twenty-first century. According to researchers, this disease affects over 50 million people worldwide. These disorders primarily affect people over the age of 65, and the World Health Organization predicts that this number will more than double in the next 30 years. Confusion, difficulty thinking, pain, muscle spasms, behavioral changes, paralysis, tremors, balance problems, coordination issues, hunched posture, and fatigue are symptoms of these disorders. These disorders are caused by age, genetics, medical history, habits, routine, and environment. This review article is focused on herbs such as Crocus sativus and Curcuma longa which are very helpful in Neurodegenerative diseases and serve as a resource for future research. Keywords: Neurodegeneration, Medicinal Herbs, Neuroprotection, Neuroprotective plants, Parkinson, Alzheimer.

The influence of accelerated brain aging on coactivation pattern dynamics in Parkinson's disease.

Aging is widely acknowledged as the primary risk factor for brain degeneration, with Parkinson's disease (PD) tending to follow accelerated aging trajectories. We aim to investigate the impact of structural brain aging on the temporal dynamics of a large-scale functional network in PD. We enrolled 62 PD patients and 32 healthy controls (HCs). The level of brain aging was determined by calculating global and local brain age gap estimates (G-brainAGE and L-brainAGE) from structural images. The neural network activity of the whole brain was captured by identifying coactivation patterns (CAPs) from resting-state functional images. Intergroup differences were assessed using the general linear model. Subsequently, a spatial correlation analysis between the L-brainAGE difference map and CAPs was conducted to uncover the anatomical underpinnings of functional alterations. Compared to HCs (-3.73 years), G-brainAGE was significantly higher in PD patients (+1.93 years), who also exhibited widespread elevation in L-brainAGE. G-brainAGE was correlated with disease severity and duration. PD patients spent less time in CAPs involving activated default mode and the fronto-parietal network (DMN-FPN), as well as the sensorimotor and salience network (SMN-SN), and had a reduced transition frequency from other CAPs to the DMN-FPN and SMN-SN CAPs. Furthermore, the pattern of localized brain age acceleration showed spatial similarities with the SMN-SN CAP. Accelerated structural brain aging in PD adversely affects brain function, manifesting as dysregulated brain network dynamics. These findings provide insights into the neuropathological mechanisms underlying neurodegenerative diseases and imply the possibility of interventions for modifying PD progression by slowing the brain aging process.

Distinct Longitudinal Brain White Matter Microstructure Changes and Associated Polygenic Risk of Common Psychiatric Disorders and Alzheimer’s Disease in the UK Biobank

BackgroundDuring the course of adulthood and aging, white matter (WM) structure and organization are characterized by slow degradation processes such as demyelination and shrinkage. An acceleration of such aging processes has been linked to the development of a range of diseases. Thus, an accurate description of healthy brain maturation, particularly in terms of WM features, is fundamental to the understanding of aging. MethodsWe used longitudinal diffusion magnetic resonance imaging to provide an overview of WM changes at different spatial and temporal scales in the UK Biobank (UKB) (n = 2678; agescan 1 = 62.38 ± 7.23 years; agescan 2 = 64.81 ± 7.1 years). To examine the genetic overlap between WM structure and common clinical conditions, we tested the associations between WM structure and polygenic risk scores for the most common neurodegenerative disorder, Alzheimer’s disease, and common psychiatric disorders (unipolar and bipolar depression, anxiety, obsessive-compulsive disorder, autism, schizophrenia, attention-deficit/hyperactivity disorder) in longitudinal (n = 2329) and cross-sectional (n = 31,056) UKB validation data. ResultsOur findings indicate spatially distributed WM changes across the brain, as well as distributed associations of polygenic risk scores with WM. Importantly, brain longitudinal changes reflected genetic risk for disorder development better than the utilized cross-sectional measures, with regional differences giving more specific insights into gene-brain change associations than global averages. ConclusionsWe extend recent findings by providing a detailed overview of WM microstructure degeneration on different spatial levels, helping to understand fundamental brain aging processes. Further longitudinal research is warranted to examine aging-related gene-brain associations.

Neuronal cell cycle reentry events in the aging brain are more prevalent in neurodegeneration and lead to cellular senescence.

Increasing evidence indicates that terminally differentiated neurons in the brain may recommit to a cell cycle-like process during neuronal aging and under disease conditions. Because of the rare existence and random localization of these cells in the brain, their molecular profiles and disease-specific heterogeneities remain unclear. Through a bioinformatics approach that allows integrated analyses of multiple single-nucleus transcriptome datasets from human brain samples, these rare cell populations were identified and selected for further characterization. Our analyses indicated that these cell cycle-related events occur predominantly in excitatory neurons and that cellular senescence is likely their immediate terminal fate. Quantitatively, the number of cell cycle re-engaging and senescent neurons decreased during the normal brain aging process, but in the context of late-onset Alzheimer's disease (AD), these cells accumulate instead. Transcriptomic profiling of these cells suggested that disease-specific differences were predominantly tied to the early stage of the senescence process, revealing that these cells presented more proinflammatory, metabolically deregulated, and pathology-associated signatures in disease-affected brains. Similarly, these general features of cell cycle re-engaging neurons were also observed in a subpopulation of dopaminergic neurons identified in the Parkinson's disease (PD)-Lewy body dementia (LBD) model. An extended analysis conducted in a mouse model of brain aging further validated the ability of this bioinformatics approach to determine the robust relationship between the cell cycle and senescence processes in neurons in this cross-species setting.

Brain morphometry and estimation of aging brain in subjects with congenital untreated isolated GH deficiency.

Individuals with isolated GH deficiency (IGHD) due to a mutation in the GHRH receptor gene have a normal life expectancy and above 50years of age, similar total cognitive performance, with better attention and executive function than controls. Our objectives were to evaluate their brain morphometry and brain aging using MRI. Thirteen IGHD and 14 controls matched by age, sex, and education, were enrolled. Quantitative volumetric data and cortical thickness were obtained by automatic segmentation using Freesurfer software. The volume of each brain region was normalized by the intracranial volume. The difference between the predicted brain age estimated by MRI using a trained neuronal network, and the chronological age, was obtained. p < 0.005 was considered significant and 0.005 < p < 0.05 as a suggestive evidence of difference. In IGHD, most absolute values of cortical thickness and regional brain volumes were similar to controls, but normalized volumes were greater in the white matter in the frontal pole and in the insula bilaterally, and in the gray matter, in the right insula and in left Caudate (p < 0.005 for all comparisons) We also noticed suggestive evidence of a larger volume in IGHD in left thalamus (p = 0.006), right thalamus (p = 0.025), right caudate (p = 0.046) and right putamen (p = 0.013). Predicted brain ages were similar between groups. IGHD is primarily associated with similar absolute brain measurements, and a set of larger normalized volumes, and does not appear to alter the process of brain aging.

PSYCHOGERONTOLOGICAL SUPPORT FOR DEMENTIATED ELDERLY PEOPLE

Psychopegerontological work has as its main objective the search for autonomy and independence for the elderly, helping to understand and accept the emotions and thoughts generated by the difficulties existing in the problems encountered at this stage of life. Understanding the concept of old age, aging, the brain aging process, and its pathologies are the key pieces for beginning good prevention and intervention work with the elderly. Stimulating their cognitive abilities in a preventive and interventional way is the focus of this study and the way in which psychopedagogy adds and contributes to multidisciplinary work and well-being based on autonomy and independence of the elderly and their families.

Brain Age Prediction Based on Quantitative Susceptibility Mapping Using the Segmentation Transformer.

The process of brain aging is intricate, encompassing significant structural and functional changes, including myelination and iron deposition in the brain. Brain age could act as a quantitative marker to evaluate the degree of the individual's brain evolution. Quantitative susceptibility mapping (QSM) is sensitive to variations in magnetically responsive substances such as iron and myelin, making it a favorable tool for estimating brain age. In this study, we introduce an innovative 3D convolutional network named Segmentation-Transformer-Age-Network (STAN) to predict brain age based on QSM data. STAN employs a two-stage network architecture. The first-stage network learns to extract informative features from the QSM data through segmentation training, while the second-stage network predicts brain age by integrating the global and local features. We collected QSM images from 712 healthy participants, with 548 for training and 164 for testing. The results demonstrate that the proposed method achieved a high accuracy brain age prediction with a mean absolute error (MAE) of 4.124 years and a coefficient of determination (R2) of 0.933. Furthermore, the gaps between the predicted brain age and the chronological age of Parkinson's disease patients were significantly higher than those of healthy subjects (P<0.01). We thus believe that using QSM-based predicted brain age offers a more reliable and accurate phenotype, with the potentiality to serve as a biomarker to explore the process of advanced brain aging.

CIRCULATING IMMUNE CELLS ARE ASSOCIATED WITH BRAIN MRI MEASUREMENTS IN THE FRAMINGHAM OFFSPRING

Abstract Mounting evidence supports the role of the immune system in brain health, yet little is known about the role of circulating immune cells in brain health. We investigated the association of immune cell phenotypes with brain MRI phenotypes in the Framingham Heart Study Offspring participants who attended Exam 7 (mean age 61, 52% women). Immune cells (43 analyzed here) were determined by flow cytometry and previously published. Analysis of the immune cell phenotypes with MRI measurements of 13 brain regions revealed several significant associations, adjusting for age, sex and CMV status (Model 1) in the full sample (n=703) and the CMV+ stratum (n=327). In the full sample, higher senescent/exhausted CD8+ cells (CD8+CD45RO-CCR7-CD27-(Teff), CD8+CD45RA+CD28-CD57+(TEMRA), CD8+CD27-CD28-) associated with higher cerebrum and frontal gray volumes. These associations were strengthened when cardiovascular risk factors were included in the model (Model 2). In the CMV+ stratum, two CD8+ cell types (TEMRA, and Teff) were significantly associated with higher cerebrum gray and frontal gray matter volumes in both models. Also in the CMV+ stratum, higher levels of CD8+CD45RO+CCR7+CD27+ (Central Memory) were associated with lower frontal gray matter, and higher CD3+ (T cells) cells were associated with higher temporal gray matter and higher CD8 Teff associated with lower cerebrum white volumes. There were no associations of CD4 subtypes with brain MRI measures in the full sample or the CMV+ stratum. These associations with brain volumes in adults aged 40-88 may improve understanding of the role of the immune system early in the brain aging process.

COMPARISON OF DNA METHYLATION IN SALIVA, BUFFY COAT AND PBMC SAMPLES IN CATSLIFE

Abstract The design of the Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging (CATSLife) allows for separation of genetic and environmental factors affecting health and cognitive aging. Currently, this sample is transitioning through midlife. One goal of this study is to identify epigenetic changes associated with aging, however methylation profiles differ across tissue types. Therefore, we describe here the analysis of DNA methylation in three CATSLife sample types: saliva, buffy coat, and peripheral blood mononuclear cells (PBMCs). Obtaining saliva is least invasive, although it may be less informative about brain and cognitive aging processes. In contrast, while buffy coats and PBMCs may be more informative, obtaining blood is more invasive. Buffy coats are less expensive to obtain than PBMCs, however they contain more cell types which may complicate analysis. Our analyses of 91 participants, suggested that saliva samples were less likely to pass initial quality control (&amp;lt; 96% CpGs detected). Unsurprisingly, the buffy coat and PBMC DNA methylation signatures are more similar to each other (r=0.97) than either is to saliva (rs=0.88—0.92). In initial analyses, each sample type demonstrated expected familial/heritable patterns of similarity across sites (MZ twins &amp;gt; DZ twins &amp;gt; biological &amp; adoptive siblings). Given the additional cost of isolating PBMCs and computational methods to account for complex cell mixtures, the use of buffy coat DNA increases accessibility to analyze epigenetic changes longitudinally, enabling the early identification of epigenetic biomarkers of cognitive decline and the effect of both genes and environments on this process.

Real‐time Memory‐related Neurofeedback Training Improves Intrinsic Brain Oscillations in Older Adults

AbstractBackgroundMild cognitive impairment (MCI), manifesting as working memory deficits for example, is the most common and earliest symptom of Alzheimer’s disease and related dementias (AD/ADRD). To combat the brain aging processes, early intervention is needed. Electroencephalogram (EEG)‐based neurofeedback (NF) has been found to be beneficial in treating a variety of brain disorders. Increased intrinsic delta power and decreased alpha is associated with brain aging and AD pathologies. We have developed an ERP‐based NF protocol to reward memory‐related potentials. In this study, we aim to evaluate the effect of NF training protocol.MethodThree older males (ages, 63, 78, and 79) participated in a newly developed NF training protocol including baseline and memory‐related NF training (twice a week). Each participant was recorded using 90‐second of eyes closed (EC) before multiple NF sessions during each visit. Their brain signals were collected with a 14‐channel wireless electroencephalogram (EEG) headset and processed in real‐time. The NF training contained 2 sham sessions followed by 2 intervention sessions. Compared to the intervention, visual feedback in the sham was provided in random order rather than triggered by participants’ ERP fluctuations. The EEG signal collected with EC before the experiment (Baseline, T0), 3 days after the sham (Sham, T1), and 3 days after the intervention (post‐intervention, T2) were preprocessed as 4s epoch windows and computed as the delta, theta, alpha, beta, and gamma band power. The average EEG band powers from T0, T1, and T2 and memory performances from the three participants were calculated.ResultThe working memory performance (accuracy and reaction times during retrievals of memory target and rejection of nontarget) did not show significant change among the three participants. In contrast, the EC intrinsic delta and alpha power changed towards brainwaves seen in younger brains after several sessions of NF training. Additionally, sham also improves in the alpha band (associated with attention and vigilance).ConclusionThe pilot results demonstrated the effectiveness of a newly developed NF training using working memory related potentials in two out of three older adults. The results indicate the promise of cognitive enhancement using event‐related potentials‐based NF training in real time.

Methylglyoxal accumulation contributes to accelerated brain aging in spontaneously hypertensive rats

While it is well-acknowledged that neurovascular dysfunction in hypertension is tightly associated with accelerated brain aging, we contend that the deleterious effects of hypertension may extend beyond affecting only the arteries. Methylglyoxal (MG) derived from glycolysis, is involved in the accumulation of advanced glycated end products (AGEs), which are the hallmarks of neurodegenerative disorders. Therefore, the present study aims to firstly investigate the role of MG metabolism in the hypertension-accelerated brain aging process. The results of our study indicate that the levels of MG increase with age in both the plasma and hippocampus of SHRs at 12, 16, and 30 weeks old. AGE methylglyoxal-hydro imidazoline-1 (MG-H1) is primarily localized in astrocytes, while its presence was not observed in neurons and microglia within the hypertensive hippocampus. Our observations also suggest that angiotensin II (Ang II) enhances glucose uptake and glycolysis while reducing the expression of Glo1 in cultured astrocytes. N-acetylcysteine (NAC) was found to counteract the increase in escape latency and inhibit the activation of the AGEs-RAGE axis in 30-week-old SHRs. NAC decreased Iba-1 immunofluorescence intensity, inhibited the levels of pro-inflammatory markers, and enhanced the abundance of anti-inflammatory markers in the hippocampus of SHRs. Moreover, NAC reduced the immunofluorescence signal of 4HNE and increased the content of GSH and SOD in SHRs. Finally, NAC was observed to inhibit apoptosis in the hippocampus of SHRs. Collectively, we firstly showed the enhanced accumulation of MG in the hypertensive brain, whereas the clearance of MG by NAC treatment mitigated the aging process and attenuated AGEs generation, neuroinflammation, and oxidative damage.

The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment.

As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.

Multi-Scale Label-Free Human Brain Imaging with Integrated Serial Sectioning Polarization Sensitive Optical Coherence Tomography and Two-Photon Microscopy.

The study of aging and neurodegenerative processes in the human brain requires a comprehensive understanding of cytoarchitectonic, myeloarchitectonic, and vascular structures. Recent computational advances have enabled volumetric reconstruction of the human brain using thousands of stained slices, however, tissue distortions and loss resulting from standard histological processing have hindered deformation-free reconstruction. Here, the authorsdescribe an integrated serial sectioning polarization-sensitive optical coherence tomography (PSOCT) and two photon microscopy (2PM) system to provide label-free multi-contrast imaging of intact brain structures, including scattering, birefringence, and autofluorescence of human brain tissue. The authors demonstrate high-throughput reconstruction of 4 × 4 × 2cm3 sample blocks and simple registration between PSOCT and 2PM images that enablecomprehensive analysis of myelin content, vascular structure, and cellular information. The high-resolution 2PM images provide microscopic validation and enrichment of the cellular information provided by the PSOCT optical properties on the same sample, revealing the densely packed fibers, capillaries, and lipofuscin-filled cell bodies in the cortex and white matter. It is shown that theimaging system enables quantitative characterization of various pathological features in aging process, including myelin degradation, lipofuscin accumulation, and microvascular changes, which opens up numerous opportunities in the study of neurodegenerative diseases in the future.