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R. L. O’Gorman S.-S. Poil D. Brandeis P. Klaver S. Bollmann C. Ghisleni R. Lüchinger E. Martin A. Shankaranarayanan D. C. Alsop L. Michels 《Brain topography》2013,26(3):442-457
While several studies have investigated interactions between the electroencephalography (EEG) and functional magnetic resonance imaging BOLD signal fluctuations, less is known about the associations between EEG oscillations and baseline brain haemodynamics, and few studies have examined the link between EEG power outside the alpha band and baseline perfusion. Here we compare whole-brain arterial spin labelling perfusion MRI and EEG in a group of healthy adults (n = 16, ten females, median age: 27 years, range 21–48) during an eyes closed rest condition. Correlations emerged between perfusion and global average EEG power in low (delta: 2–4 Hz and theta: 4–7 Hz), middle (alpha: 8–13 Hz), and high (beta: 13–30 Hz and gamma: 30–45 Hz) frequency bands in both cortical and sub-cortical regions. The correlations were predominately positive in middle and high-frequency bands, and negative in delta. In addition, central alpha frequency positively correlated with perfusion in a network of brain regions associated with the modulation of attention and preparedness for external input, and central theta frequency correlated negatively with a widespread network of cortical regions. These results indicate that the coupling between average EEG power/frequency and local cerebral blood flow varies in a frequency specific manner. Our results are consistent with longstanding concepts that decreasing EEG frequencies which in general map onto decreasing levels of activation. 相似文献
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SS Poil R Hardstone HD Mansvelder K Linkenkaer-Hansen 《The Journal of neuroscience》2012,32(29):9817-9823
Criticality has gained widespread interest in neuroscience as an attractive framework for understanding the character and functional implications of variability in brain activity. The metastability of critical systems maximizes their dynamic range, storage capacity, and computational power. Power-law scaling-a hallmark of criticality-has been observed on different levels, e.g., in the distribution of neuronal avalanches in vitro and in vivo, but also in the decay of temporal correlations in behavioral performance and ongoing oscillations in humans. An unresolved issue is whether power-law scaling on different organizational levels in the brain-and possibly in other hierarchically organized systems-can be related. Here, we show that critical-state dynamics of avalanches and oscillations jointly emerge in a neuronal network model when excitation and inhibition is balanced. The oscillatory activity of the model was qualitatively similar to what is typically observed in recordings of human resting-state MEG. We propose that homeostatic plasticity mechanisms tune this balance in healthy brain networks, and that it is essential for critical behavior on multiple levels of neuronal organization with ensuing functional benefits. Based on our network model, we introduce a concept of multi-level criticality in which power-law scaling can emerge on multiple time scales in oscillating networks. 相似文献
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Teresa Montez Simon-Shlomo Poil Bethany F. Jones Ilonka Manshanden Jeroen P. A. Verbunt Bob W. van Dijk Arjen B. Brussaard Arjen van Ooyen Cornelis J. Stam Philip Scheltens Klaus Linkenkaer-Hansen 《Proceedings of the National Academy of Sciences of the United States of America》2009,106(5):1614-1619
Encoding and retention of information in memory are associated with a sustained increase in the amplitude of neuronal oscillations for up to several seconds. We reasoned that coordination of oscillatory activity over time might be important for memory and, therefore, that the amplitude modulation of oscillations may be abnormal in Alzheimer disease (AD). To test this hypothesis, we measured magnetoencephalography (MEG) during eyes-closed rest in 19 patients diagnosed with early-stage AD and 16 age-matched control subjects and characterized the autocorrelation structure of ongoing oscillations using detrended fluctuation analysis and an analysis of the life- and waiting-time statistics of oscillation bursts. We found that Alzheimer's patients had a strongly reduced incidence of alpha-band oscillation bursts with long life- or waiting-times (< 1 s) over temporo-parietal regions and markedly weaker autocorrelations on long time scales (1–25 seconds). Interestingly, the life- and waiting-times of theta oscillations over medial prefrontal regions were greatly increased. Whereas both temporo-parietal alpha and medial prefrontal theta oscillations are associated with retrieval and retention of information, metabolic and structural deficits in early-stage AD are observed primarily in temporo-parietal areas, suggesting that the enhanced oscillations in medial prefrontal cortex reflect a compensatory mechanism. Together, our results suggest that amplitude modulation of neuronal oscillations is important for cognition and that indices of amplitude dynamics of oscillations may prove useful as neuroimaging biomarkers of early-stage AD. 相似文献
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Mohamed A. Yassin Mohamed O. Abdel Rahman Anas A. Hamad Abdul Razzakh Poil Mohamed T. Abdelrazek Radwa M. Hussein Nancy A. Kassem Afraa M. Fadul Sarah A. Elkourashy Abdulqadir J. Nashwan 《Medicine》2020,99(51)
The main aim of this study is to compare the 2 medications denosumab and zoledronic acid for patients with beta-thalassemia major induced osteoporosis. Patients with B-thalassemia major induced osteoporosis will undergo baseline assessment of the bone densitometry by bone density(DEXA) scan as a standard of care by the radiology department, then a blood test for bone-specific alkaline phosphatase and type-1 collagen telopeptide will be measured by the chemistry laboratory.Patients with B-thalassemia major induced osteoporosis, who are 18 years of age or more and willing to participate in the study will be enrolled after consenting by the primary investigator in hematology outpatient clinics. Patients with osteoporosis will receive 1 of the 2 medications; at the end of the year, DEXA scan will be done to compare the response of the 2 medications. The potential risks include drug-related side effects.The outcome will be measured biochemically by measuring bone-specific alkaline phosphatase and type 1 collagen carboxy telopeptide and radiologically by DEXA scan at baseline and 1 year using Z score. 相似文献
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Steffen Bollmann Carmen Ghisleni Simon-Shlomo Poil Ernst Martin Juliane Ball Dominique Eich-Höchli 《The world journal of biological psychiatry》2017,18(4):279-290
Objectives: Attention-deficit/hyperactivity disorder (ADHD) has been associated with spatial working memory as well as frontostriatal core deficits. However, it is still unclear how the link between these frontostriatal deficits and working memory function in ADHD differs in children and adults. This study examined spatial working memory in adults and children with ADHD, focussing on identifying regions demonstrating age-invariant or age-dependent abnormalities. Methods: We used functional magnetic resonance imaging to examine a group of 26 children and 35 adults to study load manipulated spatial working memory in patients and controls. Results: In comparison to healthy controls, patients demonstrated reduced positive parietal and frontostriatal load effects, i.e., less increase in brain activity from low to high load, despite similar task performance. In addition, younger patients showed negative load effects, i.e., a decrease in brain activity from low to high load, in medial prefrontal regions. Load effect differences between ADHD and controls that differed between age groups were found predominantly in prefrontal regions. Age-invariant load effect differences occurred predominantly in frontostriatal regions. Conclusions: The age-dependent deviations support the role of prefrontal maturation and compensation in ADHD, while the age-invariant alterations observed in frontostriatal regions provide further evidence that these regions reflect a core pathophysiology in ADHD. 相似文献
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Poil SS Jansen R van Aerde K Timmerman J Brussaard AB Mansvelder HD Linkenkaer-Hansen K 《The European journal of neuroscience》2011,34(3):394-403
Ongoing neuronal oscillations in vivo exhibit non-random amplitude fluctuations as reflected in a slow decay of temporal auto-correlations that persist for tens of seconds. Interestingly, the decay of auto-correlations is altered in several brain-related disorders, including epilepsy, depression and Alzheimer's disease, suggesting that the temporal structure of oscillations depends on intact neuronal networks in the brain. Whether structured amplitude modulation occurs only in the intact brain or whether isolated neuronal networks can also give rise to amplitude modulation with a slow decay is not known. Here, we examined the temporal structure of cholinergic fast network oscillations in acute hippocampal slices. For the first time, we show that a slow decay of temporal correlations can emerge from synchronized activity in isolated hippocampal networks from mice, and is maximal at intermediate concentrations of the cholinergic agonist carbachol. Using zolpidem, a positive allosteric modulator of GABA(A) receptor function, we found that increased inhibition leads to longer oscillation bursts and more persistent temporal correlations. In addition, we asked if these findings were unique for mouse hippocampus, and we therefore analysed cholinergic fast network oscillations in rat prefrontal cortex slices. We observed significant temporal correlations, which were similar in strength to those found in mouse hippocampus and human cortex. Taken together, our data indicate that fast network oscillations with temporal correlations can be induced in isolated networks in vitro in different species and brain areas, and therefore may serve as model systems to investigate how altered temporal correlations in disease may be rescued with pharmacology. 相似文献
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Human brain oscillations fluctuate erratically in amplitude during rest and exhibit power-law decay of temporal correlations. It has been suggested that this dynamics reflects self-organized activity near a critical state. In this framework, oscillation bursts may be interpreted as neuronal avalanches propagating in a network with a critical branching ratio. However, a direct comparison of the temporal structure of ongoing oscillations with that of activity propagation in a model network with critical connectivity has never been made. Here, we simulate branching processes and characterize the activity propagation in terms of avalanche life-time distributions and temporal correlations. An equivalent analysis is introduced for characterizing ongoing oscillations in the alpha-frequency band recorded with magnetoencephalography (MEG) during rest. We found that models with a branching ratio near the critical value of one exhibited power-law scaling in life-time distributions with similar scaling exponents as observed in the MEG data. The models reproduced qualitatively the power-law decay of temporal correlations in the human data; however, the correlations in the model appeared on time scales only up to the longest avalanche, whereas human data indicate persistence of correlations on time scales corresponding to several burst events. Our results support the idea that neuronal networks generating ongoing alpha oscillations during rest operate near a critical state, but also suggest that factors not included in the simple classical branching process are needed to account for the complex temporal structure of ongoing oscillations during rest on time scales longer than the duration of individual oscillation bursts. 相似文献
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Sonja Simpraga Huibert D. Mansvelder Geert Jan Groeneveld Samantha Prins Ellen P. Hart Simon-Shlomo Poil Klaus Linkenkaer-Hansen 《Clinical neurophysiology》2018,129(11):2325-2332
Objectives
Cognitive impairment models are used in clinical studies aimed at proving pharmacology of drugs being developed for Alzheimer’s disease and other cognitive disorders. Due to rising interest in nicotinic agonists, we aimed to establish a method to monitor neurophysiological effects of modulating the nicotinic cholinergic system.Methods
In a four-way cross-over study, eyes-closed rest EEG was recorded in 28 healthy subjects receiving mecamylamine—a nicotinic acetylcholine receptor (nAChR) antagonist, which induces temporary cognitive dysfunction in healthy subjects—with co-administration of placebo, nicotine or galantamine.Results
Using machine learning to optimally contrast the effects of 30?mg of mecamylamine and placebo on the brain, we developed a nAChR index that consists of 10 EEG biomarkers and shows high classification accuracy (~95% non-cross-validated, ~70% cross-validated). Importantly, using the nAChR index, we demonstrate reversal of mecamylamine-induced neurophysiological effects due to 16?mg of galantamine as well as administering 21?mg of nicotine transdermally.Conclusions
Our findings indicate that the mecamylamine challenge model jointly with the nAChR index—a measure of the nicotinic EEG profile—could aid future proof-of-pharmacology studies to demonstrate effects of nicotinic cholinergic compounds.Significance
This novel measure for quantifying nicotinic cholinergic effects on the EEG could serve as a useful tool in drug development of pro-cognitive compounds. 相似文献
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