1,132 research outputs found

    Evidence that neurovascular coupling underlying the BOLD effect increases with age during childhood

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    Functional MRI using blood–oxygen‐level‐dependent (BOLD) imaging has provided unprecedented insights into the maturation of the human brain. Task‐based fMRI studies have shown BOLD signal increases with age during development (ages 5–18) for many cognitive domains such as language and executive function, while functional connectivity (resting‐state) fMRI studies investigating regionally synchronous BOLD fluctuations have revealed a developing functional organization of the brain from a local into a more distributed architecture. However, interpretation of these results is confounded by the fact that the BOLD signal is directly related to blood oxygenation driven by changes in blood flow and only indirectly related to neuronal activity, and may thus be affected by changing neuronal–vascular coupling. BOLD signal and cerebral blood flow (CBF) were measured simultaneously in a cohort of 113 typically developing awake participants ages 3–18 performing a narrative comprehension task. Using a novel voxelwise wild bootstrap analysis technique, an increased ratio of BOLD signal to relative CBF signal change with age (indicative of increased neuronal–vascular coupling) was seen in the middle temporal gyri and the left inferior frontal gyrus. Additionally, evidence of decreased relative oxygen metabolism (indicative of decreased neuronal activity) with age was found in the same regions. These findings raise concern that results of developmental BOLD studies cannot be unambiguously attributed to neuronal activity. Astrocytes and astrocytic processes may significantly affect the maturing functional architecture of the brain, consistent with recent research demonstrating a key role for astrocytes in mediating increased CBF following neuronal activity and for astrocyte processes in modulating synaptic connectivity. Hum Brain Mapp, 36:1–15, 2015 . © 2014 Wiley Periodicals, Inc .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110113/1/hbm22608.pd

    Accumulation Of Subcortical Iron As A Modifier Of Volumetric And Cognitive Decline In Healthy Aging: Two Longitudinal Studies

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    Accumulation of non-heme iron in the brain has been theorized as a cellular mechanism underlying global neural and cognitive decline in normal aging and neurodegenerative disease. Relatively few studies of brain iron in normal aging exist and extant studies are almost exclusively cross-sectional. Here, I estimated iron content via T2* and measured volumes in several brain regions in two independent samples of healthy adults. The first sample (N = 89) was measured twice with a two-year delay; and the second sample (N = 32) was assessed four times over a span of 7 years. Latent models estimated change in iron and volume, and the effects of cardiovascular risk factors as modifiers of change trajectories. Iron significantly increased (T2* decreased) over time in the basal ganglia, but not in the hippocampus. Accumulation of iron accounted for shrinkage in the striatum. Elevated metabolic syndrome risk indicators were associated with greater iron at baseline, which accounted for individual differences in shrinkage. Increase in caudate iron content was associated directly with lesser improvement in virtual Morris water maze navigation, and indirectly via shrinkage with lesser improvement in verbal working memory. This study present the first longitudinal evidence in support of iron as a biomarker of age-related decline in regional volume and cognition

    Emerging Knowledge From Noninvasive Imaging Studies: Is Ammonia Control Enough?

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    Multiple lines of research suggest that ammonia is harmful to the brain if the levels remain elevated for extended periods of time. Several decades ago, there was no testing or standard of care to monitor the effect of hyperammonemia (HA) on neurological function in urea cycle disorders (UCD), and the timing of HA encephalopathy is still not clear. Magnetic resonance imaging (MRI) was not done routinely, if at all, so it was not known what changes were occurring in the brain, during and after recovery from HA. Decades ago, a diagnosis of a UCD meant severe disability and early death. Earlier diagnosis, improved management, and nitrogen scavenger therapy have improved the lives and life span of patients with UCD. However, many patients suffer from learning difficulties under the umbrella “executive function” which comprises neurologically based skills involving mental control and self-regulation. The general agreement of the core elements of executive functions includes inhibition, working memory, and cognitive flexibility and is necessary in development of skills in reasoning, fluid intelligence, problem-solving, and planning. Our research focuses on the use of noninvasive neuroimaging coupled with neuropsychological testing to understand the complex relationship between ammonia, glutamine, cognitive function, seizures, and specifically impact on development of working memory

    Chocolate, Air Pollution and Children's Neuroprotection: What Cognition Tools should be at Hand to Evaluate Interventions?

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    IndexaciĂłn: Web of ScienceMillions of children across the world are exposed to multiple sources of indoor and outdoor air pollutants, including high concentrations of fine particulate matter (PM2.5) and ozone (O-3). The established link between exposure to PM2.5, brain structural, volumetric and metabolic changes, severe cognitive deficits (1.5-2 SD from average IQ) in APOE 4 heterozygous females with >75 - <94% BMI percentiles, and the presence of Alzheimer's disease (AD) hallmarks in urban children and young adults necessitates exploration of ways to protect these individuals from the deleterious neural effects of pollution exposure. Emerging research suggests that cocoa interventions may be a viable option for neuroprotection, with evidence suggesting that early cocoa interventions could limit the risk of cognitive and developmental concerns including: endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, and metabolic detrimental brain effects. Currently, however, it is not clear how early we should implement consumption of cocoa to optimize its neuroprotective effects. Moreover, we have yet to identify suitable instruments for evaluating cognitive responses to these interventions in clinically healthy children, teens, and young adults. An approach to guide the selection of cognitive tools should take into account neuropsychological markers of cognitive declines in patients with Alzheimer's neuropathology, the distinct patterns of memory impairment between early and late onset AD, and the key literature associating white matter integrity and poor memory binding performance in cases of asymptomatic familial AD. We highlight potential systemic and neural benefits of cocoa consumption. We also highlight Working Memory Capacity (WMC) and attention control tasks as opened avenues for exploration in the air pollution scenario. Exposures to air pollutants during brain development have serious brain consequences in the short and long term and reliable cognition tools should be at hand to evaluate interventions.http://journal.frontiersin.org/article/10.3389/fphar.2016.00232/ful

    The Role of Aerobic Glycolysis in the Resting Human Brain

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    The human brain accounts for 2% of total body weight, though it consumes 20% of the body\u27s energy supply. Most of this energy is provided by the complete oxidation of glucose to carbon dioxide and water, though some fraction of glucose undergoes aerobic glycolysis without concomitant oxidative phosphorylation. Elevation in neuronal activity increases aerobic glycolysis due to the disproportionate increase in blood flow and glucose utilization greater than oxygen consumption. Since aerobic glycolysis produces significantly less energy than complete oxidation of glucose, its role in cellular activities has been overlooked, though its presence in the resting brain has been known for several decades. In this thesis, we investigate three aspects of resting aerobic glycolysis using positron emission tomography. First, we characterize the regional distribution of aerobic glycolysis in the awake, eyes closed human brain. We show that brain regions with high levels of functional activity in the resting state, including the default network and prefrontal cortex, have elevated aerobic glycolysis. In addition, we show that aerobic glycolysis is modulated by prior task performance. Performance of a complex visuomotor rotation learning task increases aerobic glycolysis in premotor cortex for several hours following task completion. Further, we show that regional brain metabolism is correlated to neurotransmitter receptor density. Aerobic glycolysis is highest in regions with a balanced density of excitatory and inhibitory receptors. Taken together, these results demonstrate the functional significance of resting aerobic glycolysis and its modulation by transient functional activity. These data provide supporting evidence for the synaptic homeostasis hypothesis, indicating elevation in brain metabolism, specifically aerobic glycolysis, during wakefulness associated with alterations in synaptic strength and receptor density

    Blood and neuroimaging biomarkers of cognitive sequelae in breast cancer patients throughout chemotherapy:A systematic review

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    Breast cancer treatment can induce alterations in blood-and neuroimaging-based markers. However, an overview of the predictive value of these markers for cognition is lacking for breast cancer survivors. This systematic review summarized studies of the last decade, using the PubMed database, evaluating blood markers, and the association between blood-or structural neuroimaging markers and cognition across the chemotherapy trajectory for primary breast cancer, following PRISMA guidelines. Forty-four studies were included. Differences were observed in all blood marker categories, from on-therapy until years post-chemotherapy. Associations were found between cognitive functioning and (1) blood markers (mainly inflammation-related) during, shortly-, or years post-chemotherapy and (2) white and gray matter metrics in frontal, temporal and parietal brain regions months up until years post-chemotherapy. Preliminary evidence exists for epigenetic and metabolic changes being associated with cognition, only after chemotherapy. This review demonstrated time-dependent associations between specific blood-based and structural neuroimaging markers with cognitive impairment in patients with breast cancer. Future studies are encouraged to include both neuroimaging-and blood markers (e.g. of neuronal integrity, epigenetics and metabolism) to predict long-term cognitive effects of chemotherapy

    Kaasaegsete kognitiivsete ja sotsiaalsete sekkumistehnikate loomine pediaatrilises neurorehabilitatsioonis ajukahjustusega lastel

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    VĂ€itekirja elektrooniline versioon ei sisalda publikatsiooneOmandatud ajukahjustusega lapsed vajavad kaasuva kognitiivse ja sotsiaalse defitsiidi diagnostikat ja rehabilitatsiooni, mis on oluline lapse akadeemilise edukuse ja elukvaliteedi parandamisel. Neurorehabilitatsioon on plaanipĂ€rane sekkumine, mille eesmĂ€rk on kompenseerida vĂ”i kergendada ajukahjustusest pĂ”hjustatud defitsiiti. Antud doktoritöö eesmĂ€rk oli uute arvutipĂ”histe meetodite kasutuselevĂ”tmine omandatud ajukahjustusega laste kognitiivses ja sotsiaalses neurorehabilitatioonis. Treeningdisainid loodi tĂ€helepanu, ruumitaju ja sotsiaalse kompetentsi hĂ€irete raviks. Uuringus osales 59 epilepsia, ajutrauma vĂ”i tikkide diagnoosiga ja 47 tervet kontrollgrupi last vanuses 8–12 aastat. Patsiendid lĂ€bisid rehabilitatsiooni (10 treeningut) koos eelneva ja treeningujĂ€rgse testimisega. TĂ€helepanu ja ruumitaju treeningus kasutati arvutipĂ”hist ForamenRehab lastele kohandatud programmi vĂ€ljatöötatud treeningprotokollidega. Sotsiaalsete hĂ€irete raviks loodi esmalt struktureeritud neurorehabilitatsiooni mudel, mis koosnes sotsiaalse kompetentsi olulistest komponentidest, nende hindamismeetoditest ja rehabilitatsiooni vahenditest: puutetundlikud lauad Snowflake Multiteach Tabletop ja Diamond Touch Table, ning virtuaalreaalsuse keskkonnad. Tulemusena esines patsientidel treeningu eelselt vĂ€ljendunud tĂ€helepanu, ruumitaju ja sotsiaalse kompetentsi defitsiit. ArvutipĂ”hised ja virtuaalreaalsuse programmid olid efektiivsed kognitiivsete hĂ€irete ravis. Patsientidel esines treeningute jĂ€rgselt oluline paranemine kahes tĂ€helepanu komponendis (tĂ€helepanu jagamine ja seiramine) ja kolmes ruumitaju komponendis (visuaal-konstruktiivsed vĂ”imed, visuaalne tĂ€helepanu ja nĂ€gemis-ruumitaju) ning raviefekt oli sĂ€ilinud jĂ€reltestimisel 1,3 aastat hiljem. Sotsiaalse rehabilitatsiooni jĂ€rgselt paranesid oluliselt patsientide vaimuteooria (Theory of Mind) ja emotsioonide Ă€ratundmine, kasutati rohkem koostööoskuseid, verbaalset ja mitteverbaalset kommunikatsiooni ning pragmaatika oskuseid. Uuringute tugevuseks oli sajaprotsendiline ravisoostumus ning positiivne tagasiside. Olulised on töö kĂ€igus vĂ€lja töötatud teaduspĂ”hised sekkumisprotokollid ja uued tehnoloogiapĂ”hised rehabilitatsioonimeetodid hĂ€irunud funktsioonide spetsiifiliseks raviks lastel.Children with acquired brain injury (ABI) need diagnosis of accompanying cognitive and socio-emotional deficits and neurorehabilitation to enhance their future academic success and quality of life. Neurorehabilitation is a systematic intervention designed to compensate for or remediate the impairments caused by brain injury. The main aim of the thesis was implementing new computer-based programs, multitouch-multiuser tabletops and virtual reality in cognitive and social neurorehabilitation for children with ABI. Rehabilitation designs were developed for the treatment of attention, visuospatial, and social competence deficits. 59 children aged 8–12 years with ABI diagnosis (epilepsy, traumatic brain injury or tic disorder) and 47 healthy controls participated. Study group patients completed 10 training sessions guided by therapists. Pre-intervention assessments, and outcome assessments immediately and 1.31 years after the rehabilitation were carried out. ForamenRehab computer-programme was adapted to children and intervention protocols were created for attention and visuospatial function remediation. For social deficit remediation, the structured neurorehabilitation model was created, composed of the main components of social competence with evaluation and intervention tools: Snowflake Multiteach Tabletop, Diamond Touch Table and virtual reality programmes. Pre-intervention assessments showed that children with ABI had significant deficits in attention, visuospatial abilities and social competence functions. Computer-based and virtual reality programs were effective in the remediation of cognitive deficits in patients. After training, the patients had improved performance in two attention (complex attention and tracking) and three visuospatial components (visual organization, visual attention and visuospatial perception). The positive training effect had preserved after 1.3 years in follow-up assessments. Additionally, after social deficit rehabilitation, the patients showed improvements in Theory of Mind and emotion recognition, and they used more cooperation, communication, and pragmatic skills. The patients’ compliance was 100% and feedback was positive for all three interventions. In sum, the developed evidence-based intervention protocols and new technology-based rehabilitation methods are important in the remediation of specific cognitive deficits in children.https://www.ester.ee/record=b528718

    Hippocampus

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    The hippocampus is a bicortical structure with extensive fiber connections with multiple brain regions. It is involved in several functions, such as learning, memory, attention, emotion, and more. This book covers various aspects of the hippocampus including cytoarchitecture, functions, diseases, and treatment. It highlights the most advanced findings in research on the hippocampus. It discusses circuits, pattern formation process of grid cells, and zinc dynamics of the hippocampus. The book also addresses the tau pathology and circRNAs related to Alzheimer’s disease and potential treatment strategies. It is a useful resource for general readers, students, and researchers
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