Successful brain aging: plasticity, environmental enrichment, and lifestyle

Age-related differences in resting glutamate levels and glutamate uptake in the hippocampus and frontal cortex of C57BL/6 mice

In normal aging, little is known in human and animal models about functional changes to glutamate neuronal systems that may contribute to age-related cognitive differences. The present studies investigated glutamate neuronal signaling in the hippocampus (dentate gyrus) and frontal cortex (infralimbic) of young adult (3-8 months), middle-aged (10-13 months), and aged (15-27 months) male and female C57BL/6 mice using microelectrode electrode array (MEA) recording technology to measure second-by-second resting levels of glutamate in anesthetized mice. Glutamate regulation was investigated in vivo by inhibiting the uptake of glutamate by local application of the competitive non-transportable blocker of excitatory amino acid transporters DL-threo-beta-benzyloxyaspartate (TBOA). Resting levels of glutamate and TBOA-induced changes in extracellular glutamate concentration were reliably measured in the hippocampus and frontal cortex of young adult, middle-aged, and aged mice and were seen to significantly increase in aging in the hippocampus. In the frontal cortex we observed an increase only in the middle-aged animals. TBOA produced robust changes in extracellular glutamate in the hippocampus and frontal cortex which showed significant changes in the kinetics of the signals in the middle-aged mice. Interestingly, the variance of the resting glutamate levels in the hippocampus of aged female mice was greater than in aged male mice, supporting a possible age-related gender difference in glutamate function. Taken together, these data support that glutamate signaling in the hippocampus and frontal cortex of aged mice is affected in normal aging with changes in glial regulation of glutamate uptake observed from the TBOA effects in the middle-aged mice.

An integrated approach to understanding the effects of exposome on neuroplasticity

Anthropogenic factors are those that occur due to human activities. The exposome is proposed to complement the genome, wherein an individual's exposure begins before birth. The range of exposures includes physical, chemical, dietary, lifestyle, biological, and occupational sources. Exposome has a positive or negative influence on neuroplasticity during different stages of life. A comprehensive study of the exposome is thus necessary to incorporate these factors and their influence on the individual, community, and the population as a whole. Exposomic research and global health present significant opportunities for interdisciplinary research. This review gives an overview of the exposome and its influence on neuroplasticity. It proposes methods to study the exposome on neuroplasticity across the lifespan of the individual. This is possible with the use of self-reported data, large-scale cohort formation, physiological sensors, neuroimaging, omics, molecular biology, and systems approaches. These approaches aim to provide a holistic understanding of an individual's neurological well-being and its implications for the population at large. This will also enable the designing of novel preventive and treatment strategies for managing neurological disorders.

A comprehensive review of neurotransmitter modulation via artificial intelligence: A new frontier in personalized neurobiochemistry

The deployment of artificial intelligence (AI) is revolutionizing neuropharmacology and drug development, allowing the modulation of neurotransmitter systems at the personal level. This review focuses on the neuropharmacology and regulation of neurotransmitters using predictive modeling, closed-loop neuromodulation, and precision drug design. The fusion of AI with applications such as machine learning, deep-learning, and even computational modeling allows for the real-time tracking and enhancement of biological processes within the body. An exemplary application of AI is the use of DeepMind's AlphaFold to design new GABA reuptake inhibitors for epilepsy and anxiety. Likewise, Benevolent AI and IBM Watson have fast-tracked drug repositioning for neurodegenerative conditions. Furthermore, we identified new serotonin reuptake inhibitors for depression through AI screening. In addition, the application of Deep Brain Stimulation (DBS) settings using AI for patients with Parkinson's disease and for patients with major depressive disorder (MDD) using reinforcement learning-based transcranial magnetic stimulation (TMS) leads to better treatment. This review highlights other challenges including algorithm bias, ethical concerns, and limited clinical validation. Their proposal to incorporate AI with optogenetics, CRISPR, neuroprosthesis, and other advanced technologies fosters further exploration and refinement of precision neurotherapeutic approaches. By bridging computational neuroscience with clinical applications, AI has the potential to revolutionize neuropharmacology and improve patient-specific treatment strategies. We addressed critical challenges, such as algorithmic bias and ethical concerns, by proposing bias auditing, diverse datasets, explainable AI, and regulatory frameworks as practical solutions to ensure equitable and transparent AI applications in neurotransmitter modulation.

Advanced Brain Age Prediction Using Multi-Head Self-Attention: A Comparative Analysis of Western and Middle Eastern MRI Datasets

Brain age estimation is a critical biomarker for early detection of neurodegenerative diseases, but existing models are primarily trained on Western datasets, limiting their applicability to diverse populations. Recent studies suggest that brain aging patterns vary across ethnic groups, highlighting the need for more inclusive and adaptable AI-driven neuroimaging models. We trained our model on 4,635 healthy individuals (40-80 years) from ADNI, OASIS-3, Cam-CAN, and IXI, using 80% of data (n=3700) for training and 20% (n=935) for testing. The model was further tested on a Middle Eastern dataset (107 subjects, Tehran, Iran). It integrates multi-head self-attention along with residual connections to enhance long-range spatial feature learning, improving upon previous CNN models. Performance was evaluated using mean absolute error (MAE). The model achieved state-of-the-art accuracy (MAE = 1.99 years) on the Western test set, while being much lighter than previous models (approximately 3 million parameters); however, it performed significantly worse on the ME dataset (best MAE = 4.35 years, final = 5.83 years). Bias correction did not improve performance, indicating population-specific brain aging differences. These findings emphasize the need for diverse training datasets and cross-population adaptation techniques.

Maintaining Brain Health: The Impact of Physical Activity and Fitness on the Aging Brain-A UK Biobank Study

The growing prevalence of physical and neurological disorders linked to aging poses significant challenges for society. Many of these disorders are closely linked to changes in brain structure and function, highlighting the importance of identifying protective factors that can preserve brain structure in later life and mitigate age-related decline. Physical activity (PA) is consistently linked to physical health and was found to mitigate age-related disorders. However, its effects on markers of brain aging remain inconclusive, partly due to reliance on underpowered studies and self-reported data. We investigated the effects of accelerometer-measured PA and physical fitness on BrainAGE, a machine-learning-derived marker of brain aging, in a large UK Biobank cohort. Using cortical and subcortical neuroimaging-derived features, a BrainAGE model was trained on 21,442 participants (mean absolute error: 3.75 years) and applied to predict BrainAGE for an independent sample of 10,874 participants. Accelerometer-measured moderate-intensity PA, but not self-reported PA, was associated with decelerated brain aging, indicated by a negative BrainAGE. Further, higher hand grip strength, along with lower body mass index (BMI), diastolic blood pressure (DBP), and resting heart rate, was linked to decelerated aging. These fitness measures impacted BrainAGE independently of PA. Additionally, fitness partially accounted for the relationship between PA and BrainAGE. Specifically, BMI, DBP, and resting heart rate showed a significant mediating effect, while grip strength did not. These findings highlight the interplay between PA and fitness in maintaining brain health and provide valuable insights for neuroscience and preventive health measures.

Effectiveness of Integrated Care for Older Pepole (ICOPE) in Improving Intrinsic Capacity in Older Adults: A Systematic Review and Meta-Analysis

OBJECTIVE

Conduct a systematic review of existing studies on intrinsic capacity (IC) and a meta-analysis of studies to assess the overall effectiveness of ICOPE in improving IC in older adults.

METHODS

Ten databases were systematically searched from inception to November 8, 2023, and the search was last updated on January 2, 2024. Randomised controlled trials (RCTs) were included. The main outcomes were IC (cognition, psychological, sensory, vitality and locomotion).

RESULTS

The results showed ICOPE had a significant effect in improving cognitive function (SMD = 0.36; 95% CI, 0.17 to 0.56, p < 0.001, 12 RCTs, 7926 participants) and depressive symptoms (SMD = -0.70; 95% CI, -0.96 to -0.43, p < 0.001, 26 RCTs, 11,034 participants), but there was no statistically significant difference in improving locomotion (SMD = 0.16; 95% CI, -0.03 to 0.34, p = 0.098, 3 RCTs, 1580 participants). Meta-regression analysis shows that intervention duration should be paid attention to when the source of heterogeneity is discussed on the cognition.

CONCLUSION

The results suggest that ICOPE may be a potentially effective approach to help improve the IC in older adults, showing significant potential for improving cognitive function and reducing depressive symptoms in particular.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

ICOPE is expected to provide effective strategies to enhance issues such as IC and may be an innovative way to improve the overall health of older adults. This result provides strong support for geriatric nursing practice and encourages the adoption of ICOPE as a viable nursing approach to promote healthy ageing.

[Physiology of aging: An update and genetic point of view]

Aging is a physiological process resulting from the accumulation of molecular and cellular damage over time, leading to a gradual decline in overall physical and mental health. Throughout this temporal continuum, various physiological alterations occur in the organism, modifying the individual's response to multiple stimuli and adverse factors. At the same time, an increasingly significant manifestation of genetic modifications is observed, which are intrinsically interconnected with the dynamics of these adaptive processes. The geriatric population is characterized by its high prevalence in hospital settings, particularly in critical care units, where admissions from this group account for nearly 50% of total admissions. Thus, acquiring and updating knowledge is relevant and necessary to ensure a more effective therapeutic approach for geriatric patients.

Characterization of a natural model of adult mice with different rate of aging

Aging is a heterogeneous process, so individuals of the same age may be aging at a different rate. A natural model of premature aging in mice have been proposed based on the poor response to the T-maze. Those that take longer to cross the intersection are known as Prematurely Aging Mice (PAM), while those that show an exceptional response are known as Exceptional non-PAM (E-NPAM), being the rest non-PAM (NPAM). Although many aspects of PAM and E-NPAM have been described, some aspects of their brain aging have not been studied. Similarly, it is known that PAM, NPAM and E-NPAM show a different rate of aging and longevity, but the differences between these three groups in behavior, immune function and oxidative-inflammatory state are unknown. The present study aims to deepen the study of brain aging in PAM and E-NPAM, and to study the differences in behavior, immunity, and oxidative-inflammatory state of peritoneal leukocytes between PAM, NPAM and E-NPAM. Results show deteriorated brains in PAM. Moreover, NPAM show an oxidative state similar to E-NPAM, an anxiety similar to PAM, and an intermediate immunity and lifespan between PAM and E-NPAM. In conclusion, immune function seems to be more associated with the longevity achieved.

Investigation of Metabolic and Inflammatory Disorder in the Aging FGF21 Knockout Mouse

Aging is a physiological condition accomplished with persistent low-grade inflammation and metabolic disorders. FGF21 has been reported to act as a potent longevity determinant, involving inflammatory response and energy metabolism. In this study, we engineered aging FGF21 knockout mice of 36-40 weeks and observed that FGF21 deficiency manifests a spontaneous inflammatory response of lung and abnormal accumulation of lipids in liver. On one hand, inflamed state in lungs and increased circulating inflammatory cytokines were found in FGF21 knockout mice of 36-40 weeks. To evaluate the ability of FGF21 to suppress inflammation, a subsequent study found that FGF21 knockout aggravated LPS-induced pulmonary exudation and inflammatory infiltration in mice, while exogenous administration of FGF21 reversed these malignant phenotypes by enhancing microvascular endothelial junction. On the other hand, FGF21 knockout induces fatty liver in aging mice, characterized by excessive accumulation of triglycerides within hepatocytes. Further quantitative metabolomics and lipidomics analysis revealed perturbed metabolic profile in liver lacking FGF21, including disrupted glucose and lipids metabolism, glycerophospholipid metabolism, and amino acid metabolism. Taken together, this investigation reveals the protective role of FGF21 during aging by weakening the inflammatory response and balancing energy metabolism.

Mitigation of aging-related plasticity decline through taurine supplementation and environmental enrichment

Aging-related biochemical changes in nerve cells lead to dysfunctional synapses and disrupted neuronal circuits, ultimately affecting vital processes such as brain plasticity, learning, and memory. The imbalance between excitation and inhibition in synaptic function during aging contributes to cognitive impairment, emphasizing the importance of compensatory mechanisms. Fear conditioning-related plasticity of the somatosensory barrel cortex, relying on the proper functioning and extensive up regulation of the GABAergic system, in particular interneurons containing somatostatin, is compromised in aging (one-year-old) mice. The present research explores two potential interventions, taurine supplementation, and environmental enrichment, revealing their effectiveness in supporting learning-induced plasticity in the aging mouse brain. They do not act through a mechanism normalizing the Glutamate/GABA balance that is disrupted in aging. Still, they allow for increased somatostatin levels, an effect observed in young animals after learning. These findings highlight the potential of lifestyle interventions and diet supplementation to mitigate age-related cognitive decline by promoting experience-dependent plasticity.

Effectiveness of integrated care for older adults-based interventions on depressive symptoms: A systematic review and meta-analysis

AIM

To pool existing studies to assess the overall effectiveness of integrated care for older adults (ICOPE)-based interventions in improving depressive symptoms in older adults.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Ten databases were systematically searched from inception to 15 July 2023 and the search was last updated on 2 September 2023.

METHODS

Standardized mean difference (SMD) was calculated using random effects models. RoB 2 and GRADEpro GDT were used to assess the methodological quality and confidence in the cumulative evidence. Funnel plots, egger's test and begg's test were used to analyse publication bias. Sensitivity, subgroup and meta-regression analyses were performed to explore potential sources of heterogeneity.

RESULTS

The results of 18 studies showed ICOPE-based interventions had a significant effect on improving depressive symptoms (SMD = -.84; 95% CI, -1.20 to -.3647; p < .001; 18 RCTs, 5010 participants; very low-quality evidence). Subgroup analysis showed the intervention group was characterized by mean age (70-80 years old), intervention duration between 6 to 12 months, gender (female <50%), non-frail older adults, depressed older adults and mixed integration appeared to be more effective. Sensitivity analysis found the results to be robust.

CONCLUSION

ICOPE-based interventions may be a potentially effective alternative approach to reduce depressive symptoms in the older adults.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

Healthcare professionals are expected to use ICOPE as one of the interventions for depressive symptoms in older adults, and this ICOPE could provide more comprehensive care services for older adults to reduce depressive symptoms.

IMPACT

ICOPE-based interventions may be a potentially effective alternative approach to reduce depressive symptoms in the older adults. ICOPE-based interventions had a significant effect on reducing depressive symptoms in the older adults. The intervention group characterized by mean age of older adults, intervention duration, gender ratio, health condition and integration types may influence the effect size.

REPORTING METHOD

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

PATIENT OR PUBLIC CONTRIBUTION

No Patient or Public Contribution.

Overlooked cases of mild cognitive impairment: Implications to early Alzheimer's disease

Mild cognitive impairment (MCI) marks the initial phase of memory decline or other cognitive functions like language or spatial perception, while individuals typically retain the capacity to carry out everyday tasks independently. Our comprehensive article investigates the intricate landscape of cognitive disorders, focusing on MCI and Alzheimer's disease (AD) and Alzheimer's disease-related dementias (ADRD). The study aims to understand the signs of MCI, early Alzheimer's disease, and healthy brain aging while assessing factors influencing disease progression, pathology development and susceptibility. A systematic literature review of over 100 articles was conducted, emphasizing MCI, AD and ADRD within the elderly populations. The synthesis of results reveals significant findings regarding ethnicity, gender, lifestyle, comorbidities, and diagnostic tools. Ethnicity was found to influence MCI prevalence, with disparities observed across diverse populations. Gender differences were evident in cognitive performance and decline, highlighting the need for personalized management strategies. Lifestyle factors and comorbidities were identified as crucial influencers of cognitive health. Regarding diagnostic tools, the Montreal Cognitive Assessment (MoCA) emerged as superior to the Mini-Mental State Examination (MMSE) in early MCI detection. Overall, our article provides insights into the multifaceted nature of cognitive disorders, emphasizing the importance of tailored interventions and comprehensive assessment strategies for effective cognitive health management.

Grandfathers-to-Grandsons Transgenerational Transmission of Exercise Positive Effects on Cognitive Performance

Physical exercise is a robust lifestyle intervention known for its enhancement of cognitive abilities. Nevertheless, the extent to which these benefits can be transmitted across generations (intergenerational inheritance to F1, and transgenerational to F2 and beyond) remains a topic of limited comprehension. We have already shown that cognitive improvements resulting from physical exercise can be inherited from parents to their offspring, proving intergenerational effects. So, we set out to explore whether these enhancements might extend transgenerationally, impacting the F2 generation. In this study, we initially examined the behavioral traits of second generation (F2) male mice, whose grandfathers (F0) had an exercise intervention. Our findings revealed that F2 mice with physically active grandpaternal F0 progenitors displayed significantly improved memory recall, encompassing both spatial and non-spatial information when compared to their counterparts from sedentary F0 progenitors, and proving for the first time the transgenerational inheritance of physical exercise induced cognitive enhancement. Surprisingly, while F2 memory improved (as was the case with F1), adult hippocampal neurogenesis remained unchanged between experimental and control groups (unlike in F1). Additionally, our analysis of small RNA sequences in the hippocampus identified 35 differentially expressed miRNAs linked to important brain function categories. Notably, two of these miRNAs, miRNA-144 and miRNA-298, displayed a robust negative correlation with cognitive performance. These findings highlight the enduring transgenerational transmission of cognitive benefits associated with exercise, even after two generations, suggesting that moderate exercise training can have lasting positive effects, possibly orchestrated by a specific set of miRNAs that exert their influence across multiple generations.

Cognitive Reserve proxies can modulate motor and non-motor basal ganglia circuits in early Parkinson's Disease

Parkinson's Disease (PD) is hallmarked by dysfunctional circuitry between the basal ganglia and dorsolateral-prefrontal cortex. Recently progress has been made in understanding factors contributing to differential susceptibility to pathology mitigating disease-related cognitive decline. Cognitive reserve, the brain processing resources accumulated throughout life while engaged in mentally stimulating activities, can play an important protective role in cognitive performance. We tested the hypothesis that Cognitive Reserve proxies may exert an impact on the basal ganglia and dorsolateral-prefrontal atrophy in early PD. Forty-five early patients with PD and 20 age-gender-matched healthy controls (HC) completed the Cognitive Reserve Index questionnaire to quantify Cognitive Reserve proxies by three indexes (CRI-Education, CRI-Working Activity, CRI-Leisure Time) and a structural MRI examination (3T). Morphometrical indexes for basal ganglia (bilateral putamen, caudate, pallidum volume) and dorsolateral-prefrontal cortex (cortical thickness) were computed. Significant differences between HC and PD were tested by direct comparisons in demographics, cognitive level, and cognitive reserve proxies indexes. Then two multiple regression analyses were performed to identify predictors of the basal ganglia and dorsolateral-prefrontal cortex structural integrity. Regression analysis revealed that basal ganglia volume was significantly predicted by CRI-Education (pFDR = 0.029), sex (pFDR = 0.029), and Total Intracranial Volume (pFDR < 0.001). Instead, the dorsolateral-prefrontal thickness was predicted by CRI-Leisure Time (pFDR = 0.030) and age (pFDR = 0.010). Cognitive Reserve proxies, especially education and leisure-time activities, can play a protective role on the structural integrity of the basal ganglia and dorsolateral-prefrontal cortex, respectively, critical regions hallmarking brain status of early phases of PD.

Effect of physio-cognitive dual-task training on cognition in pre-ageing and older adults with neurocognitive disorders: A meta-analysis and meta-regression of randomized controlled trial

Declines in cognitive performance, such as those seen in neurocognitive disorders (NCDs) are often associated with ageing. Both physical activity and cognitive training are common interventional strategies that can mitigate the decline in cognitive and physical performance. This review aims to (1) to evaluate the effects of Physio-Cognitive Dual-task Training (PCDT) intervention on cognition, physical performance, activities of daily living (ADL) and health-related quality of life (HRQoL) in pre-ageing and older adults with neurocognitive disorders, (2) explore the effects of covariates on intervention outcomes. A systematic search was conducted in eight databases. Cochrane's Risk of Bias Tool version 1 and GRADE criteria were used to assess risk of bias and certainty of evidence, respectively. Meta-analysis and meta-regression analyses were conducted using R software. Twenty-six randomized controlled trials involving 1,949 pre-ageing and older adults with NCDs were included in the meta-analysis. PCDT interventions had small-to-medium effect size on all cognition outcomes (g = 0.40-0.52) and instrumental ADL (g == 0.42), and a large effect size on HRQoL (g = 0.72). The quality of evidence was rated moderate to low for the outcome measures in pre-ageing and older adults with NCDs. These findings highlight the importance of PCDT interventions in preventing and slowing down cognitive impairment in pre-ageing and older adults. Registration: PROSPERO Number (CRD42020213962).

Environmental Enrichment Improves Motor Function and Muscle Transcriptome of Aged Mice

Aging results in the progressive decline of muscle strength. Interventions to maintain muscle strength may mitigate the age-related loss of physical function, thus maximizing health span. The work on environmental enrichment (EE), an experimental paradigm recapitulating aspects of an active lifestyle, has revealed EE-induced metabolic benefits mediated by a brain-fat axis across the lifespan of mice. EE initiated at 18-month of age shows a trend toward an increased mean lifespan. While previous work described EE's influences on the aging dynamics of several central-peripheral processes, its influence on muscle remained understudied. Here, the impact of EE is investigated on motor function, neuromuscular physiology, and the skeletal muscle transcriptome. EE is initiated in 20-month-old mice for a five-month period. EE mice exhibit greater relative lean mass that is associated with improved mobility and hindlimb grip strength. Transcriptomic profiling of muscle tissue reveals an EE-associated enrichment of gene expression within several metabolic pathways related to oxidative phosphorylation and the TCA cycle. Many mitochondrial-related genes-several of which participate in the electron transport chain-are upregulated. Stress-responsive signaling pathways are downregulated because of EE. The results suggest that EE improves motor function-possibly through preservation of mitochondrial function-even late in life.

The association of white matter connectivity with prevalence, incidence and course of depressive symptoms: The Maastricht Study

BACKGROUND

Altered white matter brain connectivity has been linked to depression. The aim of this study was to investigate the association of markers of white matter connectivity with prevalence, incidence and course of depressive symptoms.

METHODS

Markers of white matter connectivity (node degree, clustering coefficient, local efficiency, characteristic path length, and global efficiency) were assessed at baseline by 3 T MRI in the population-based Maastricht Study (n = 4866; mean ± standard deviation age 59.6 ± 8.5 years, 49.0% women; 17 406 person-years of follow-up). Depressive symptoms (9-item Patient Health Questionnaire; PHQ-9) were assessed at baseline and annually over seven years of follow-up. Major depressive disorder (MDD) was assessed with the Mini-International Neuropsychiatric Interview at baseline only. We used negative binominal, logistic and Cox regression analyses, and adjusted for demographic, cardiovascular, and lifestyle risk factors.

RESULTS

A lower global average node degree at baseline was associated with the prevalence and persistence of clinically relevant depressive symptoms [PHQ-9 ⩾ 10; OR (95% confidence interval) per standard deviation = 1.21 (1.05-1.39) and OR = 1.21 (1.02-1.44), respectively], after full adjustment. On the contrary, no associations were found of global average node degree with the MDD at baseline [OR 1.12 (0.94-1.32) nor incidence or remission of clinically relevant depressive symptoms [HR = 1.05 (0.95-1.17) and OR 1.08 (0.83-1.41), respectively]. Other connectivity measures of white matter organization were not associated with depression.

CONCLUSIONS

Our findings suggest that fewer white matter connections may contribute to prevalent depressive symptoms and its persistence but not to incident depression. Future studies are needed to replicate our findings.

Effects of non-pharmacological interventions on depressive symptoms and risk of major depressive disorder in adults with subthreshold depression: A systematic review and meta-analysis

Subthreshold depression (StD) is a condition that significantly reduces the quality of life and increases the risk of developing major depressive disorder (MDD). In order to investigate the effectiveness of non-pharmacological interventions (NPIs) in preventing the onset of MDD and improving depressive symptoms in adults with StD (AStDs), we conducted a systematic search of nine databases and included a total of 15 studies. Standardized mean differences (SMDs) were calculated using random effects models. RoB2 tool and GRADEpro software were used to assess the methodological quality and evidence. Funnel plots, Egger's, and Begg's tests were used to analyze publication bias. Sensitivity, subgroup and meta-regression analyses were performed to explore potential sources of heterogeneity. The results showed that NPIs had a significant effect in preventing the onset of MDD and improving depressive symptoms. Subgroup analysis revealed that NPIs were particularly effective in general adult populations, during short-term follow-up (FU) periods, among pregnant women, and in universal prevention programs. The results were found to be robust and credible, as they were less sensitive to changes in the analysis method. Timely detection and treatment of StD is feasible and important, as it can effectively delay or prevent the onset of MDD.

Cognitive-motor interventions based on virtual reality and instrumental activities of daily living (iADL): an overview

Non-invasive, non-pharmacological interventions utilizing virtual reality (VR) represent a promising approach to enhancing cognitive function in patients with degenerative cognitive disorders. Traditional "pen and paper" therapies often lack the practical engagement in everyday activities that older individuals encounter in their environment. These activities pose both cognitive and motor challenges, underscoring the necessity of understanding the outcomes of such combined interventions. This review aimed to assess the advantages of VR applications that integrate cognitive-motor tasks, simulating instrumental activities of daily living (iADLs). We systematically searched five databases-Scopus, Web of Science, Springer Link, IEEE Xplore, and PubMed, from their inception until January 31, 2023. Our review revealed that motor movements, coupled with VR-based cognitive-motor interventions, activate specific brain areas and foster improvements in general cognition, executive function, attention, and memory. VR applications that meld cognitive-motor tasks and simulate iADLs can offer significant benefits to older adults. Enhanced cognitive and motor performance can promote increased independence in daily activities, thereby contributing to improved quality of life.

[Touch, a crucial sense in social interactions to improve homeostasis in aging and promote healthy longevity]

Aging is associated with the generalized deterioration of the organism, being of great relevance experienced by homeostatic systems such as the nervous, immune, and endocrine systems, which increases the risk of morbidity and mortality. Among the lifestyle strategies that have been researched to improve these systems and achieve greater healthy longevity, this review will focus on the social environment. In order to verify the effectiveness of these both in the improvement of homeostasis and in life expectancy, the research carried out with experimental animals that have allowed this to be done will be discussed. In addition, as it has been observed that physical contact is crucial for the positive outcomes of social interaction on homeostatic systems and longevity to occur, we will focus on that mechanism, as well as some of the possible molecular pathways underlying the effects found.

The effect of weight loss following 18 months of lifestyle intervention on brain age assessed with resting-state functional connectivity

Background

Obesity negatively impacts multiple bodily systems, including the central nervous system. Retrospective studies that estimated chronological age from neuroimaging have found accelerated brain aging in obesity, but it is unclear how this estimation would be affected by weight loss following a lifestyle intervention.

Methods

In a sub-study of 102 participants of the Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed Study (DIRECT-PLUS) trial, we tested the effect of weight loss following 18 months of lifestyle intervention on predicted brain age based on magnetic resonance imaging (MRI)-assessed resting-state functional connectivity (RSFC). We further examined how dynamics in multiple health factors, including anthropometric measurements, blood biomarkers, and fat deposition, can account for changes in brain age.

Results

To establish our method, we first demonstrated that our model could successfully predict chronological age from RSFC in three cohorts (n=291;358;102). We then found that among the DIRECT-PLUS participants, 1% of body weight loss resulted in an 8.9 months' attenuation of brain age. Attenuation of brain age was significantly associated with improved liver biomarkers, decreased liver fat, and visceral and deep subcutaneous adipose tissues after 18 months of intervention. Finally, we showed that lower consumption of processed food, sweets and beverages were associated with attenuated brain age.

Conclusions

Successful weight loss following lifestyle intervention might have a beneficial effect on the trajectory of brain aging.

Funding

The German Research Foundation (DFG), German Research Foundation - project number 209933838 - SFB 1052; B11, Israel Ministry of Health grant 87472511 (to I Shai); Israel Ministry of Science and Technology grant 3-13604 (to I Shai); and the California Walnuts Commission 09933838 SFB 105 (to I Shai).

An Overview

Nowadays, China has rapidly progressed into an aging society and is faced with huge challenges on public health. Aging is accompanied by the structural and functional alterations in the brain, which leads to the cognitive decline in the elderly and acts as the primary risk factor for dementia. However, the aging brain has not been well understood at a systemic level. This chapter presents the definition of brain health, the aging situation in China, an overview of the BABRI, the purpose of writing this book, and the introductions of the chapters, respectively, which will contribute to knowledge of the underlying mechanisms of healthy and pathological aging of the brain.

The microbiota-gut- hippocampus axis

Introduction

It is well known that the intestinal bacteria substantially affect physiological processes in many body organs. Especially, through a bidirectional communication called as gut-microbiota-brain axis, the gut microbiota deeply influences development and function of the nervous system. Hippocampus, as a part of medial temporal lobe, is known to be involved in cognition, emotion, and anxiety. Growing evidence indicates that the hippocampus is a target of the gut microbiota. We used a broad search linking the hippocampus with the gut microbiota and probiotics.

Methods

All experimental studies and clinical trials published until end of 2021 were reviewed. Influence of the gut microbiota on the behavioral, electrophysiological, biochemical and histological aspects of the hippocampus were evaluated in this review.

Results

The effect of disrupted gut microbiota and probiotic supplements on the microbiota-hippocampus link is also considered. Studies show that a healthy gut microbiota is necessary for normal hippocampus dependent learning and memory and synaptic plasticity. The known current mechanisms are production and modulation of neurotrophins, neurotransmitters and receptors, regulation of intracellular molecular processes, normalizing the inflammatory/anti-inflammatory and oxidative/antioxidant factors, and histological stability of the hippocampus. Activity of the hippocampal neuronal circuits as well as behavioral functions of the hippocampus positively respond to different mixtures of probiotic bacteria.

Discussion

Growing evidence from animal researches indicate a close association between the hippocampus with the gut microbiota and probiotic bacteria as well. However, human studies and clinical trials verifying such a link are scant. Since the most of papers on this topic have been published over the past 3 years, intensive future research awaits.

Activity-Dependent Induction of Younger Biological Phenotypes

In several mammalian species, including humans, complex stimulation patterns such as cognitive and physical exercise lead to improvements in organ function, organism health and performance, as well as possibly longer lifespans. A framework is introduced here in which activity-dependent transcriptional programs, induced by these environmental stimuli, move somatic cells such as neurons and muscle cells toward a state that resembles younger cells to allow remodeling and adaptation of the organism. This cellular adaptation program targets several process classes that are heavily implicated in aging, such as mitochondrial metabolism, cell-cell communication, and epigenetic information processing, and leads to functional improvements in these areas. The activity-dependent gene program (ADGP) can be seen as a natural, endogenous cellular reprogramming mechanism that provides deep insight into the principles of inducible improvements in cell and organism function and can guide the development of therapeutic approaches for longevity. Here, these ADGPs are analyzed, exemplary critical molecular nexus points such as cAMP response element-binding protein, myocyte enhancer factor 2, serum response factor, and c-Fos are identified, and it is explored how one may leverage them to prevent, attenuate, and reverse human aging-related decline of body function.

Interventions for preventing and ameliorating cognitive deficits in adults treated with cranial irradiation

BACKGROUND

Cognitive deficits are common in people who have received cranial irradiation and have a serious impact on daily functioning and quality of life. The benefit of pharmacological and non-pharmacological treatment of cognitive deficits in this population is unclear. This is an updated version of the original Cochrane Review published in Issue 12, 2014.

OBJECTIVES

To assess the effectiveness of interventions for preventing or ameliorating cognitive deficits in adults treated with cranial irradiation.

SEARCH METHODS

For this review update we searched the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE via Ovid, Embase via Ovid, and PsycInfo via Ovid to 12 September 2022.

SELECTION CRITERIA

We included randomised controlled (RCTs) trials that evaluated pharmacological or non-pharmacological interventions in cranial irradiated adults, with objective cognitive functioning as a primary or secondary outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors (MK, JD) independently extracted data from selected studies and carried out a risk of bias assessment. Cognitive function, fatigue and mood outcomes were reported. No data were pooled.

MAIN RESULTS

Eight studies met the inclusion criteria and were included in this updated review. Six were from the original version of the review, and two more were added when the search was updated. Nineteen further studies were assessed as part of this update but did not fulfil the inclusion criteria. Of the eight included studies, four studies investigated "prevention" of cognitive problems (during radiotherapy and follow-up) and four studies investigated "amelioration" (interventions to treat cognitive impairment as a late complication of radiotherapy). There were five pharmacological studies (two studies on prevention and three in amelioration) and three non-pharmacological studies (two on prevention and one in amelioration). Due to differences between studies in the interventions being evaluated, a meta-analysis was not possible.  Studies in early radiotherapy treatment phase (five studies) Pharmacological studies in the "early radiotherapy treatment phase" were designed to prevent or ameliorate cognitive deficits and included drugs used in dementia (memantine) and fatigue (d-threo-methylphenidate hydrochloride). Non-pharmacological studies in the "early radiotherapy treatment phase" included a ketogenic diet and a two-week cognitive rehabilitation and problem-solving programme.  In the memantine study, the primary cognitive outcome of memory at six months did not reach significance, but there was significant improvement in overall cognitive function compared to placebo, with similar adverse events across groups. The d-threo-methylphenidate hydrochloride study found no statistically significant difference between arms, with few adverse events. The study of a calorie-restricted ketogenic diet found no effect, although a lower than expected calorie intake in the control group complicates interpretation of the results.  The study investigating the utility of a rehabilitation program did not carry out a statistical comparison of cognitive performance between groups.  Studies in delayed radiation or late effect phase (four studies) The "amelioration" pharmacological studies to treat cognitive complications of radiotherapy included drugs used in dementia (donepezil) or psychostimulants (methylphenidate and modafinil). Non-pharmacological measures included cognitive rehabilitation and problem solving (Goal Management Training). These studies included patients with cognitive problems at entry who had "stable" brain cancer.  The donepezil study did not find an improvement in the primary cognitive outcome of overall cognitive performance, but did find improvement in an individual test of memory, compared to placebo; adverse events were not reported. A study comparing methylphenidate with modafinil found improvements in cognitive function in both the methylphenidate and modafinil arms; few adverse events were reported. Another  study comparing two different doses of modafinil combined treatment arms and found improvements across all cognitive tests, however, a number of adverse events were reported. Both studies were limited by a small sample size. The Goal Management Training study suggested a benefit of the intervention, a behavioural intervention that combined mindfulness and strategy training, on executive function and processing speed.  There were a number of limitations across studies and few were without high risks of bias.

AUTHORS' CONCLUSIONS

In this update, limited additional evidence was found for the treatment or amelioration of cognitive deficits in adults treated with cranial irradiation. As concluded in the original review, there is supportive evidence that memantine may help prevent cognitive deficits for adults with brain metastases receiving cranial irradiation. There is supportive evidence that donepezil, methylphenidate and modafinil may have a role in treating cognitive deficits in adults with brain tumours who have been treated with cranial irradiation; patient withdrawal affected the statistical power of these studies. Further research that tries to minimise the withdrawal of consent, and subsequently reduce the requirement for imputation procedures, may offer a higher certainty of evidence. There is evidence from only a single small study to support non-pharmacological interventions in the amelioration of cognitive deficits. Further research is required.

Dietary Habits Modify the Association of Physical Exercise with Cognitive Impairment in Community-Dwelling Older Adults

Background: Previous studies have confirmed that both healthy diets and physical exercise have preventive effects with respect to cognitive decline with aging. The aim of this study was to investigate whether the associations of physical exercise with cognitive impairment differ in community-dwelling older adults with different dietary habits. Methods: In the 2008/2009 wave of the Chinese Longitudinal Healthy Longevity Survey, 14,966 community-dwelling older adults (≥65 years) were included for analyses. Dietary habits (including daily intake of fruits, vegetables, tea, meat, fish, eggs, food made from beans, salt-preserved vegetables, sugar, garlic, milk products, nut products, mushroom or algae, vitamins and medicinal plants) and physical exercise were assessed. Cognitive impairment was evaluated using the Chinese version of the MMSE in the 2008/2009 and 2011/2012 waves. The effect modifications of physical exercise on cognitive impairment by dietary habits were estimated using logistic regression models. Results: Older adults who practiced physical exercise exhibited a trend of decreased probability of cognitive impairment at baseline and follow-up (OR = 0.92, 95% CI = 0.80–1.06, p = 0.273; OR = 0.83, 95% CI = 0.65–1.05, p = 0.123, respectively) compared with those who did not practice physical exercise. When stratified by dietary habits, physical exercise had a protective effect with respect to prevalent cognitive impairment in older adults who ate fruits (OR = 0.74, 95% CI = 0.58–0.94, p = 0.016), ate food made from beans (OR = 0.76, 95% CI = 0.62–0.93, p = 0.007), did not eat sugar (OR = 0.81, 95% CI = 0.68–0.98, p = 0.028) and ate milk products (OR = 0.75, 95% CI = 0.57–0.97, p = 0.030); in the longitudinal analyses, physical exercise had a protective effect with respect to incident cognitive impairment in older adults who ate fruits (OR = 0.63, 95% CI = 0.41–0.98, p = 0.040) and milk products (OR = 0.57, 95% CI = 0.35–0.94, p = 0.027). Fruits, food made from beans and milk products modified the associations of physical exercise with prevalent cognitive impairment (p values for interaction = 0.008, 0.005 and 0.082, respectively). Conclusions: The associations of physical exercise with cognitive impairment could be modified by certain dietary habits. Physical exercise was not found to be significantly protective with respect to cognitive impairment in older adults unless they had specific dietary habits. Thus, dietary habits should be emphasized when investigating the beneficial effects of physical exercise on cognitive function in community-dwelling older adults.

Aging, testosterone, and neuroplasticity: friend or foe?

Neuroplasticity or neural plasticity implicates the adaptive potential of the brain in response to extrinsic and intrinsic stimuli. The concept has been utilized in different contexts such as injury and neurological disease. Neuroplasticity mechanisms have been classified into neuroregenerative and function-restoring processes. In the context of injury, neuroplasticity has been defined in three post-injury epochs. Testosterone plays a key yet double-edged role in the regulation of several neuroplasticity alterations. Research has shown that testosterone levels are affected by numerous factors such as age, stress, surgical procedures on gonads, and pharmacological treatments. There is an ongoing debate for testosterone replacement therapy (TRT) in aging men; however, TRT is more useful in young individuals with testosterone deficit and more specific subgroups with cognitive dysfunction. Therefore, it is important to pay early attention to testosterone profile and precisely uncover its harms and benefits. In the present review, we discuss the influence of environmental factors, aging, and gender on testosterone-associated alterations in neuroplasticity, as well as the two-sided actions of testosterone in the nervous system. Finally, we provide practical insights for further study of pharmacological treatments for hormonal disorders focusing on restoring neuroplasticity.

Nano-Neurogenesis for CNS Diseases and Disorders

Neurogenesis encompasses the formation and development of neurons in the mammalian brain, mainly occurring in hippocampus and the olfactory system. This process is rapid, accurate, and very sensitive to the external stressors including environment, diet, age, anxiety, stress, depression, diet, and hormones. The range of stressors is big and directly impacts the generation, maturation and migration, efficacy, and myelination of the neuronal cells. The field of regenerative medicine focuses on combating the direct or indirect effects of these stressors on the process of neurogenesis, and ensures increased general and neuronal communications and functioning. Understanding the deep secrets of brain signaling and devising ways to increase drug availability is tough, considering the complexity and intricate details of the neuronal networks and signaling in the CNS. It is imperative to understand this complexity and introduce potent and efficacious ways to combat diseases. This perspective offers an insight into how neurogenesis could be aided by nanotechnology and what plausible nanomaterials are available to culminate neurogenesis-related neurological disorders. The nanomaterials are promising as they are minute, robust, and effective and help in diagnostics and therapeutics such as drug delivery, maturation and neuroprotection, neurogenesis, imaging, and neurosurgery.

Long Term Physical Activity Improves Quality of Life Perception, Healthy Nutrition, and Daily Life Management in Elderly: A Randomized Controlled Trial

Physical activity (PA) is a key element in the management of successful aging. The aim of this paper was to show the effects of PA on the quality of life perception, nutritional status, and daily life management of 178 older adults (aged 63.87 ± 8.17) randomly assigned to an Experimental Group (EG), which performed moderate-to-high intensity aerobic and strengthening training, and a Control Group (CG) which performed low-impact PA, assessed after 6, 12, and 24 months. The Short-Form Health Survey (SF-36), Mini Nutritional Assessment (MNA), and Physical Activity Scale for the Elderly (PASE) were used for the study. In the SF-36 assessment, EG showed a good quality of life perception maintained after 24 months, while CG showed a worsening in the same period (p = 0.018). The EG reported a significant better nutritional status as compared to pre-intervention assessment (p = 0.003) and to CG (p < 0.001). Regarding the PASE, the EG showed a higher level of weekly activities than the CG after 24 months (p = 0.011), while the CG showed a worsening after 12 months (p = 0.008). The prolonged engagement in moderate-to high-intensity PA allowed the maintenance of a good quality of life perception, a good level of nutritional status, and daily life activities.

Structural Plasticity of the Hippocampus in Neurodegenerative Diseases

Neuroplasticity is the capacity of neural networks in the brain to alter through development and rearrangement. It can be classified as structural and functional plasticity. The hippocampus is more susceptible to neuroplasticity as compared to other brain regions. Structural modifications in the hippocampus underpin several neurodegenerative diseases that exhibit cognitive and emotional dysregulation. This article reviews the findings of several preclinical and clinical studies about the role of structural plasticity in the hippocampus in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. In this study, literature was surveyed using Google Scholar, PubMed, Web of Science, and Scopus, to review the mechanisms that underlie the alterations in the structural plasticity of the hippocampus in neurodegenerative diseases. This review summarizes the role of structural plasticity in the hippocampus for the etiopathogenesis of neurodegenerative diseases and identifies the current focus and gaps in knowledge about hippocampal dysfunctions. Ultimately, this information will be useful to propel future mechanistic and therapeutic research in neurodegenerative diseases.

Pharmacological depletion of microglia leads to a dose-dependent reduction in inflammation and senescence in the aged murine brain

Chronic macrophage activation was implicated as one of the main culprits for chronical, low-grade inflammation which significantly contributes to development of age-related diseases. Microglia as the brain macrophages have been recently implicated as key players in neuroinflammation and neurodegeneration in the aged brain. Microglial cell functions are indispensable in early development, however, activation or senescence of microglia in aging cells may be detrimental. Depletion of microglia using genetical or pharmacological approaches leads to opposite results regarding effects on brain cognition. In this study we pharmacologically depleted microglia using orally delivered low and high doses of the CSF1R inhibitor PLX5622 and assessed the expression levels of known inflammation markers (TNF-α, IL1-β, IL-6, IL-10), glia markers (Iba-1 and Gfap) and specific senescence marker p16^Ink4a in the aged murine brain. Our results indicate that treatment with low and high doses of PLX5622 leads to a dose-dependent depletion of microglial cells with similar levels in young and aged mice. We also show that treatment with low and high PLX5622 differentially affected cytokine levels in young and old brains. By using low doses we could achieve reduction in inflammation circumventing the astrocyte activation. Removal of microglia cells led to decreased expression of the senescence marker p16^Ink4a in the aged brain, indicating a relevant contribution of these cells to the expression of this marker and their senescent status in the healthy aging brain. Our results indicate that increased and detrimental brain inflammation in aged murine brain can be impaired by selectively reducing the microglial cell population.

Age-related changes in motor cortex plasticity assessed with non-invasive brain stimulation: an update and new perspectives

It is commonly accepted that the brains capacity to change, known as plasticity, declines into old age. Recent studies have used a variety of non-invasive brain stimulation (NIBS) techniques to examine this age-related decline in plasticity in the primary motor cortex (M1), but the effects seem inconsistent and difficult to unravel. The purpose of this review is to provide an update on studies that have used different NIBS techniques to assess M1 plasticity with advancing age and offer some new perspective on NIBS strategies to boost plasticity in the ageing brain. We find that early studies show clear differences in M1 plasticity between young and older adults, but many recent studies with motor training show no decline in use-dependent M1 plasticity with age. For NIBS-induced plasticity in M1, some protocols show more convincing differences with advancing age than others. Therefore, our view from the NIBS literature is that it should not be automatically assumed that M1 plasticity declines with age. Instead, the effects of age are likely to depend on how M1 plasticity is measured, and the characteristics of the elderly population tested. We also suggest that NIBS performed concurrently with motor training is likely to be most effective at producing improvements in M1 plasticity and motor skill learning in older adults. Proposed NIBS techniques for future studies include combining multiple NIBS protocols in a co-stimulation approach, or NIBS strategies to modulate intracortical inhibitory mechanisms, in an effort to more effectively boost M1 plasticity and improve motor skill learning in older adults.

Environmental enrichment: A concept analysis

OBJECTIVES

The concept analysis of environmental enrichment aims to clarify the meaning of the term contributing to a shared understanding of its use in healthcare and future research studies. Environmental enrichment has implications in health promotion in children's development and healthy aging in the general population.

METHODS

A literature search using PubMed and CINAHL databases on environmental enrichment was conducted to identify the uses of the term from various disciplines. The keywords are "environmental enrichment", "socialization", "physical activity", "cognitive stimulation", and "experience-dependent". Human studies from 2000 to 2020 were included in the search.

RESULTS

Availability of green spaces, neighborhood safety, walkability to community centers, and accessibility of community resources are antecedents of environmental enrichment. Defining attributes are positive stimulation, interpersonal interaction, and physical engagement. The consequences of environmental enrichment are improved cognitive functioning in children, decline in memory impairment, and reduced risk of developing dementia in the elderly.

CONCLUSION

Engaging and counseling patients, family members, and the community in adverse effects of a deprived environment and the benefits of an enriched environment is a vital tenet of the nursing discipline. Understanding the optimum amount of positive stimulation, interpersonal interaction duration, and frequency are needed in future research.

Efficacy of Tai Chi-Style Multi-Component Exercise on Frontal-Related Cognition and Physical Health in Elderly With Amnestic Mild Cognitive Impairment

Early prevention from accelerated neurocognitive declines with advanced aging and the delay of the onset of dementia have became paramount for the achievement of active aging. The present study examined whether the proposed non-pharmaceutical, multi-component exercise training which combined Tai-Chi exercise, Aerobic fitness, and thera-band therapy protects against age-related neurocognitive and physical deterioration in the older participants with amnestic mild cognitive impairment (aMCI). Participants with aMCI in the quasi-experimental design were assigned to the multi-component exercise group or care control group. Evaluations of neuropsychological function and functional fitness were performed before and after 12-weeks intervention, and after 24-weeks follow-up. Our results showed that the multi-component intervention significantly improved various domains of neurocognitive function, particularly in memory- and frontal-related cognition, and better performance on functional fitness, including muscle strength, cardiopulmonary endurance, and agility. Furthermore, such beneficial effects were preserved after 24 weeks. The findings provide supportive evidence that non-pharmaceutically multi-component intervention with Tai-Chi style practice as a core exercise may protect against age-related neurocognitive and physical deficits and lay the path on developing age-friendly intervention programs to delay, or even reverse, the progression of MCI to dementia.

Interventions and cognitive functioning in adults with traumatic spinal cord injuries: a systematic review and meta-analysis

AIM

This research synthesized scientific evidence on the impact of interventions for adults with traumatic spinal cord injury on cognition, to understand if current intervention approaches are appropriate in light of the risk of post-injury cognitive impairments.

METHOD

Medline, Central, Embase, Scopus, PsycINFO and PubMed were searched for intervention in persons with SCI assessing cognition pre- and post-intervention. Study quality was completed using the National Institutes of Health quality assessment tools. Results were grouped by type of intervention. The meta-analysis involved calculation of pooled effect sizes for interventions utilizing the same cognitive measure.

RESULTS

Eleven studies of moderate quality discussed drug therapy, transcutaneous tibial nerve stimulation, diet modification and dietary supplements, and inpatient rehabilitation. Some aspects of cognition were negatively affected by drugs while diet modification and supplement use, and transcutaneous tibial nerve stimulation showed no evidence of a difference in cognitive scores when compared with no intervention. Inpatient rehabilitation revealed a small but beneficial effect, when results of seven studies were pooled.

CONCLUSION

Evidence on the effects of interventions on cognitive functioning in patients with traumatic spinal cord injury is sparse and inconclusive, so work in this area is timely. It is valuable to know not only which interventions are effective for improving cognition, but also how other commonly used interventions, intended to treat other injury sequela, can affect cognition. PROSPERO: CRD42018087238.Implications for rehabilitationHistorically, rehabilitation of patients with traumatic spinal cord injury has targeted physical impairments, with little attention to cognition; this research aimed to understand if current interventions are appropriate in light of the risk of patients' cognitive impairments. Evidence on the effects of drug therapy, diet and dietary supplements interventions on cognitive functioning in traumatic spinal cord injury is sparse and inconclusive.Combining multiple inpatient rehabilitation interventions shows a positive but heterogeneous effect on the cognitive functioning; interventions applied earlier show greater gains.A major challenge for clinicians is to select an outcome measure sensitive to change over time, and to relate the results to patients' change in cognitive abilities with intervention applicationResearch to understand the functional effect of spinal cord injury on the widely distributed networks of the central and autonomic nervous systems subserving cognition, is timely.

Effects of enriched environment on micturition activity in freely moving C57BL/6J mice

OBJECTIVES

An enriched environment (EE) has been known to promote structural changes in the brain and enhance learning and emotional performance. However, little is known about the effect of an EE on brain stem functions, such as the micturition function. In this study, we examined whether an EE affects micturition activity in mice.

METHODS

Male C57BL/6J mice were used. We assessed the micturition activity of freely moving mice using a novel system developed in-house.

RESULTS

During the dark period, but not light, the EE significantly increased voiding frequency, total voided volume, mean voided volume, voiding duration, mean flow rate, and maximum flow rate compared with the control environment. This EE effect on micturition function was associated with habituation to novel environments in the open-field test, but not with amelioration of motor coordination in the rotarod test. Interestingly, even after the mice were withdrawn from the EE, the improvements in micturition function persisted, while other behavioral changes were abolished. The relative value of voiding frequency and total voided volume during the light period, expressed as a percentage of 24 hours, increased with age when mice were reared in a standard environment. However, this age-related change was not observed in mice reared in an EE.

CONCLUSIONS

These results suggest that an EE may promote micturition activity during the active phase of C57BL/6J mice, and its effects persist even after withdrawal from the EE. Furthermore, an EE may mitigate dysfunctions in micturition activity, such as polyuria, during the resting phase in aged mice.

Seven-Day Pedometer-Assessed Step Counts and Brain Volume: A Population-Based Observational Study

BACKGROUND

To investigate the association between step counts and brain volumes (BVs)-global and 6 a priori selected cognition-related regions of interest-in Japanese men aged 40-79 years.

METHODS

The authors analyzed data from 680 cognitively intact participants of the Shiga Epidemiological Study of Subclinical Atherosclerosis-a population-based observational study. Using multivariable linear regression, the authors assessed cross-sectional associations between 7-day step counts at baseline (2006-2008) and BVs at follow-up (2012-2015) for age-stratified groups (<60 y and ≥60 y).

RESULTS

In the older adults ≥60 years, step counts at baseline (per 1000 steps) were associated with total BV at follow-up (β = 1.42, P = .022) while adjusted for potential covariates. Regions of interest-based analyses yielded an association of step counts with both prefrontal cortexes (P < .05) in older adults, while the left entorhinal cortex showed marginally significant association (P = .05). No association was observed with hippocampus, parahippocampal, cingulum, and cerebellum. No association was observed in younger adults (<60 y).

CONCLUSIONS

The authors found a positive association between 7-day step counts and BVs, including prefrontal cortexes, and left entorhinal cortex in apparently healthy Japanese men.

Environmental Enrichment Improved Cognitive Performance in Mice under Normoxia and Hypoxia

The mammalian brain modulates its microvascular network to accommodate tissue energy demand in a process referred to as angioplasticity. There is an aging effect on cognitive function and adaptive responses to hypoxia. Hypoxia-induced angiogenesis is delayed in the aging mouse brain. Additionally, it has been shown that environmental enrichment provides an environment that fosters increased physical activity and sensory stimulation for mice as compared to standard housing; this stimulation increases neuronal activity and consequently brain oxygen demand. In this study, we investigated the effect of environmental enrichment and chronic hypoxia on cognitive performance in the young (2-4 months old) and the aged mice (17-21 months old). Mice were placed in a non-enriched or an enriched environment for 4 weeks under normoxia followed by 3 weeks of hypobaric hypoxia (~0.4 atm, equivalent to 8% normobaric oxygen at sea level). Cognitive function was evaluated using the Y-maze and the novel object recognition tests in the enriched or non-enriched mice under normoxic or hypoxic conditions. In Y-maze, a high alternation rate is indicative of sustained cognition as the animals must remember which arm was entered last, so as not to re-enter it. Novel object recognition is based on the natural tendency of rodents to investigate a novel object instead of a familiar one; a higher novel object exploration rate is indicative of better cognitive function. The young mice showed a significantly higher alternation rate (%, 63 ± 7 vs. 48 ± 10, n = 8 and 10, respectively) in the Y-Maze test as compared to the aged mice. Under normoxia, the enriched mice showed an improved alternation rate (%, 63 ± 10, n = 10) in Y-Maze test and a higher novel object exploration rate (%, 68 ± 10 vs. 52 ± 10) compared to the non-enriched controls. Similar results were observed for both young and aged mice following hypoxic exposure. Our data suggests that environmental enrichment improved the cognitive performance in the young and aged mice under normoxic and hypoxic conditions.

Sex and Age Effects on Neurobehavioral Toxicity Induced by Binge Alcohol

Historically, most alcohol neurotoxicity studies were conducted in young adult males and focused on chronic intake. There has been a shift towards studying the effects of alcohol on the adolescent brain, due to alcohol consumption during this formative period disrupting the brain's developmental trajectory. Because the most typical pattern of adolescent alcohol intake is heavy episodic (binge) drinking, there has also been a shift towards the study of binge alcohol-induced neurobehavioral toxicity. It has thus become apparent that binge alcohol damages the adolescent brain and there is increasing attention to sex-dependent effects. Significant knowledge gaps remain in our understanding of the effects of binge alcohol on the female brain, however. Moreover, it is unsettling that population-level studies indicate that the prevalence of binge drinking is increasing among American women, particularly those in older age groups. Although study of adolescents has made it apparent that binge alcohol disrupts ongoing brain maturational processes, we know almost nothing about how it impacts the aging brain, as studies of its effects on the aged brain are relatively scarce, and the study of sex-dependent effects is just beginning. Given the rapidly increasing population of older Americans, it is crucial that studies address age-dependent effects of binge alcohol, and given the increase in binge drinking in older women who are at higher risk for cognitive decline relative to men, studies must encompass both sexes. Because adolescence and older age are both characterized by age-typical brain changes, and because binge drinking is the most common pattern of alcohol intake in both age groups, the knowledge that we have amassed on binge alcohol effects on the adolescent brain can inform our study of its effects on the aging brain. In this review, we therefore cover the current state of knowledge of sex and age-dependent effects of binge alcohol, as well as statistical and methodological considerations for studies aimed at addressing them.

Astroglial asthenia and loss of function, rather than reactivity, contribute to the ageing of the brain

Astroglia represent a class of heterogeneous, in form and function, cells known as astrocytes, which provide for homoeostasis and defence of the central nervous system (CNS). Ageing is associated with morphological and functional remodelling of astrocytes with a prevalence of morphological atrophy and loss of function. In particular, ageing is associated with (i) decrease in astroglial synaptic coverage, (ii) deficits in glutamate and potassium clearance, (iii) reduced astroglial synthesis of synaptogenic factors such as cholesterol, (iv) decrease in aquaporin 4 channels in astroglial endfeet with subsequent decline in the glymphatic clearance, (v) decrease in astroglial metabolic support through the lactate shuttle, (vi) dwindling adult neurogenesis resulting from diminished proliferative capacity of radial stem astrocytes, (vii) decline in the astroglial-vascular coupling and deficient blood-brain barrier and (viii) decrease in astroglial ability to mount reactive astrogliosis. Decrease in reactive capabilities of astroglia are associated with rise of age-dependent neurodegenerative diseases. Astroglial morphology and function can be influenced and improved by lifestyle interventions such as intellectual engagement, social interactions, physical exercise, caloric restriction and healthy diet. These modifications of lifestyle are paramount for cognitive longevity.

Enriching hippocampal memory function in older adults through video games

Healthy aging is accompanied by a steady cognitive decline with clear losses in memory. Animal studies have consistently demonstrated that simply modifying an animal's living environment (known as environmental enrichment) can have a positive influence on age-related cognitive decline in the hippocampus. Previously, we showed that playing immersive 3D video games can improve hippocampal-based memory in young healthy adults, suggesting that the exploration of the large open worlds of modern-day video games may act as proxy for environmental enrichment in humans. Here, we replicated our previous video game study in healthy older adults, showing that playing video games for four weeks can improve hippocampal-based memory in a population that is already experiencing age-related decline in memory. Furthermore, we showed that the improvements last for up to four weeks past the intervention, highlighting the potential of video games as intervention for age-related cognitive decline.

Central and Peripheral Neuromuscular Adaptations to Ageing

Ageing is accompanied by a severe muscle function decline presumably caused by structural and functional adaptations at the central and peripheral level. Although researchers have reported an extensive analysis of the alterations involving muscle intrinsic properties, only a limited number of studies have recognised the importance of the central nervous system, and its reorganisation, on neuromuscular decline. Neural changes, such as degeneration of the human cortex and function of spinal circuitry, as well as the remodelling of the neuromuscular junction and motor units, appear to play a fundamental role in muscle quality decay and culminate with considerable impairments in voluntary activation and motor performance. Modern diagnostic techniques have provided indisputable evidence of a structural and morphological rearrangement of the central nervous system during ageing. Nevertheless, there is no clear insight on how such structural reorganisation contributes to the age-related functional decline and whether it is a result of a neural malfunction or serves as a compensatory mechanism to preserve motor control and performance in the elderly population. Combining leading-edge techniques such as high-density surface electromyography (EMG) and improved diagnostic procedures such as functional magnetic resonance imaging (fMRI) or high-resolution electroencephalography (EEG) could be essential to address the unresolved controversies and achieve an extensive understanding of the relationship between neural adaptations and muscle decline.

Environmental enrichment, new neurons and the neurobiology of individuality

'Enriched environments' are a key experimental paradigm to decipher how interactions between genes and environment change the structure and function of the brain across the lifespan of an animal. The regulation of adult hippocampal neurogenesis by environmental enrichment is a prime example of this complex interaction. As each animal in an enriched environment will have a slightly different set of experiences that results in downstream differences between individuals, enrichment can be considered not only as an external source of rich stimuli but also to provide the room for individual behaviour that shapes individual patterns of brain plasticity and thus function.

Microbiota and memory: A symbiotic therapy to counter cognitive decline?

The process of aging underlies many degenerative disorders that arise in the living body, including gradual neuronal loss of the hippocampus that often leads to decline in both memory and cognition. Recent evidence has shown a significant connection between gut microbiota and brain function, as butyrate production by microorganisms is believed to activate the secretion of brain-derived neurotrophic factor (BDNF). To investigate whether modification of intestinal microbiota could impact cognitive decline in the aging brain, Romo-Araiza et al. conducted a study to test how probiotic and prebiotic supplementation impacted spatial and associative memory in middle-aged rats. Their results showed that rats supplemented with the symbiotic (both probiotic and prebiotic) treatment performed significantly better than other groups in the spatial memory test, though not in that of associative memory. Their data also reported that this improvement correlated with increased levels of BDNF, decreased levels of pro-inflammatory cytokines, and better electrophysiological outcomes in the hippocampi of the symbiotic group. Thus, the results indicated that the progression of cognitive impairment is indeed affected by changes in microbiota induced by probiotics and prebiotics. Potential future applications of these findings center around combatting neurodegeneration and inflammation associated not only with aging but also with the damaging posttraumatic effects of ischemic stroke.

Structural Brain Correlates of Loneliness among Older Adults

Ample evidence indicates that loneliness in old age is associated with poor bodily and mental health. However, little is known about structural cerebral correlates of loneliness in healthy older adults. We examined such correlates in a magnetic resonance imaging (MRI) subsample of 319 older adults aged 61 to 82 years drawn from the Berlin Aging Study II. Using voxel-based morphometry (VBM) and structural equation modeling (SEM), latent hierarchical regression analyses were performed to examine associations of (i) loneliness, (ii) a range of covariates, and (iii) loneliness by covariate interactions with latent brain volume estimates of brain structures known to be involved in processing, expressing, and regulating emotions. Results from whole-brain VBM analyses showed that individuals with higher loneliness scores tended to have smaller gray matter volumes in three clusters comprising (i) the left amygdala/anterior hippocampus, (ii) the left posterior parahippocampus and (iii) the left cerebellum. Significant associations and interactions between loneliness and latent factors for the amygdala and the hippocampus were confirmed with a region-of-interest (ROI)-based approach. These findings suggest that individual differences in loneliness among older adults are correlated with individual differences in the volumes of brain regions that are central to cognitive processing and emotional regulation, also after correcting for confounders such as social network size. We discuss possible mechanisms underlying these associations and their implications.