Filters








131 Hits in 5.3 sec

Fractal analysis of spontaneous fluctuations of the BOLD signal in rat brain

Peter Herman, Basavaraju G. Sanganahalli, Fahmeed Hyder, Andras Eke
2011 NeuroImage  
Analysis of task-evoked fMRI data ignores low frequency fluctuations (LFF) of the resting-state the BOLD signal, yet LFF of the spontaneous BOLD signal is crucial for analysis of resting-state connectivity  ...  We characterized the LFF of resting-state BOLD signal at 11.7T in αchloralose and domitor anesthetized rat brain and modeled the spontaneous signal as a scale-free (i.e., fractal) distribution of amplitude  ...  This work was supported by grants from National Institutes of Health (R01 MH-067528, P30 NS-52519 to FH) and from the Hungarian Scientific Research Found (OTKA-T34122 to AE).  ... 
doi:10.1016/j.neuroimage.2011.06.082 pmid:21777682 pmcid:PMC3705180 fatcat:x4svaenyrnam3iub3ee5mk6gne

Temporal scaling properties and spatial synchronization of spontaneous blood oxygenation level-dependent (BOLD) signal fluctuations in rat sensorimotor network at different levels of isoflurane anesthesia

Kun Wang, Maurits P.A. van Meer, Kajo van der Marel, Annette van der Toorn, Lijuan Xu, Yingjun Liu, Max A. Viergever, Tianzi Jiang, Rick M. Dijkhuizen
2011 NMR in Biomedicine  
Spontaneous fluctuations in the blood oxygenation level-dependent (BOLD) MRI signal during the resting state are increasingly being studied in healthy and diseased brain in humans and animal models.  ...  Yet, the relationship between functional brain status and the characteristics of spontaneous BOLD fluctuations remains poorly understood.  ...  of BOLD low-frequency fluctuation signals in sensorimotor brain regions in rats.  ... 
doi:10.1002/nbm.1556 pmid:20669170 fatcat:r7tmzicl5fcg7f2qfymawdseuu

Fractal-based Correlation Analysis for Resting State Functional Connectivity of the Rat Brain in Functional MRI [article]

Wonsang You, Joerg Stadler
2012 arXiv   pre-print
On the other hand, the low-frequency spontaneous fluctuations in the blood oxygen level dependent (BOLD) signals of functional MRI have been observed in the resting state.  ...  In addition, we show the distribution of the Hurst exponents in the rat brain.  ...  On ' the other hand, the low-frequency spontaneous fluctuations in the blood oxygen level dependent (BOLD) signals of functional MRI have been observed in the resting state.  ... 
arXiv:1202.4751v1 fatcat:zz57nkgfsfcbjptocmgvf6kwta

Role of Ongoing, Intrinsic Activity of Neuronal Populations for Quantitative Neuroimaging of Functional Magnetic Resonance Imaging–Based Networks

Fahmeed Hyder, Peter Herman, Basavaraju G. Sanganahalli, Daniel Coman, Hal Blumenfeld, Douglas L. Rothman
2011 Brain Connectivity  
In resting-state fMRI experiments, the spotlight is on regions revealed by correlations of tiny fluctuations in the baseline (or spontaneous) BOLD signal.  ...  In this article, we argue that network mapping can be improved by including neuronal energy/activity of both the information about baseline and small differences/fluctuations of BOLD signal.  ...  Acknowledgment The authors thank their colleagues at Yale for their insightful comments.  ... 
doi:10.1089/brain.2011.0032 pmid:22433047 pmcid:PMC3621320 fatcat:pqsaykiki5bc7bnsuczwsg2nhq

Pitfalls in fractal time series analysis: fMRI BOLD as an exemplary case

Andras Eke
2012 Frontiers in Physiology  
best practice in fractal analysis of empirical fMRI BOLD signals mapped throughout the brain as an exemplary case of potentially wide interest.  ...  Our recommended flowchart for the fractal characterization of spontaneous, low frequency fluctuations in fMRI BOLD will be used as the framework for this article to make certain that it will provide a  ...  This work was supported by grants from the National Institutes of Health (R01 MH-067528 and P30 NS-52519 to Fahmeed Hyder) and from the Hungarian Scientific Research Found (OTKA grants I/3 2040, T 016953  ... 
doi:10.3389/fphys.2012.00417 pmid:23227008 pmcid:PMC3513686 fatcat:hhg4eey6tbhtxjsn5fv364r2xq

The Neural Basis of Time-Varying Resting-State Functional Connectivity

Shella Dawn Keilholz
2014 Brain Connectivity  
The literature suggests that multiple brain processes may contribute to the dynamics observed, and we speculate that it may be possible to separate particular aspects of the rsMRI signal to enhance sensitivity  ...  In this article, we review findings that link changes in electrically recorded brain states to changes in the networks obtained with rsMRI and discuss some of the challenges inherent in interpretation  ...  Spontaneous fluctuations of the BOLD signal clearly contain a wealth of information about dynamic processes in the brain, and the application of appropriate analysis techniques holds the potential to enhance  ... 
doi:10.1089/brain.2014.0250 pmid:24975024 pmcid:PMC4268576 fatcat:inzw42pkvva4ndor2du65fm3vu

Correlation of BOLD Signal with Linear and Nonlinear Patterns of EEG in Resting State EEG-Informed fMRI

Galina V. Portnova, Alina Tetereva, Vladislav Balaev, Mikhail Atanov, Lyudmila Skiteva, Vadim Ushakov, Alexey Ivanitsky, Olga Martynova
2018 Frontiers in Human Neuroscience  
However, there is a lack of data on how changes in the complexity of brain dynamics derived from EEG reflect variations in the BOLD signal.  ...  Our results indicate that both spectral features of EEG frequency bands and nonlinear dynamic properties of spontaneous EEG are strongly associated with fluctuations of the BOLD signal during the resting  ...  in the EEG signal may occur much faster, reflecting nonstationary processes in both spontaneous and induced brain activity.  ... 
doi:10.3389/fnhum.2017.00654 pmid:29375349 pmcid:PMC5767270 fatcat:m6sbfibfsvhcnfy4cpyvfj3peu

Wavelet-Based Fractal Analysis of rs-fMRI for Classification of Alzheimer's Disease

Alishba Sadiq, Norashikin Yahya, Tong Boon Tang, Hilwati Hashim, Imran Naseem
2022 Sensors  
As a result, the conventional correlation of rs-fMRI signals may not accurately reflect the functional dynamic of spontaneous neuronal activities.  ...  It is established that resting-state neuroimaging data exhibit fractal behavior, manifested in the form of slow-decaying auto-correlation and power-law scaling of the power spectrum across low-frequency  ...  using rs-fMRI [22] , which reflects spontaneous BOLD time-series signal fluctuations when a subject is not undertaking any explicit tasks.  ... 
doi:10.3390/s22093102 fatcat:kd7u5hs66ngnfindtulb4jnjna

Neurophysiological Basis of Multi-Scale Entropy of Brain Complexity and Its Relationship With Functional Connectivity

Danny J. J. Wang, Kay Jann, Chang Fan, Yang Qiao, Yu-Feng Zang, Hanbing Lu, Yihong Yang
2018 Frontiers in Neuroscience  
In this work, we investigated the neurophysiological underpinnings of complexity (MSE) of electrophysiology and fMRI signals and their relations to functional connectivity (FC).  ...  Based on literature and our data, we propose that the complexity of regional neural signals may serve as an index of the brain's capacity of information processing-increased complexity may indicate greater  ...  These emerging studies support the validity of using entropy measures of rs-fMRI to characterize the spontaneous fluctuations of brain physiology and neuronal activities non-invasively at systems level  ... 
doi:10.3389/fnins.2018.00352 pmid:29896081 pmcid:PMC5986880 fatcat:w4ol6uotqzcyjc7gq2licpk4ni

Fractal analysis of resting state functional connectivity of the brain

Wonsang You, Sophie Achard, Jorg Stadler, Bernd Bruckner, Udo Seiffert
2012 The 2012 International Joint Conference on Neural Networks (IJCNN)  
The performance of these estimators was evaluated through simulation studies and the analyses of resting state functional MRI data of the rat brain.  ...  Resting state functional connectivity is significantly influenced by fractal behavior which may not directly originate from neuronal population activities of the brain.  ...  ACKNOWLEDGMENT This neuroimaging research was supported by the special project grant from the Leibniz Institute for Neurobiology, and SA was partly funded by ANR 2010 JCJC 0302 01.  ... 
doi:10.1109/ijcnn.2012.6252657 dblp:conf/ijcnn/YouASBS12 fatcat:jv265cwjrrcvzjrhw67xi2bzrm

Strobing brain thunders: Functional correlation of extreme activity events

F. Lombardi, D.R. Chialvo, H.J. Herrmann, L. de Arcangelis
2013 Chaos, Solitons & Fractals  
The recent upraise of interest in the dynamics of the brain resting activity opens a number of new and different questions.  ...  A fundamental one is related to the character of correlations of healthy large scale brain activity. These studies focus on the linear correlation of the spontaneous activity between brain sites.  ...  The analysis performed on extreme events in BOLD signals suggests that activity variations with opposite sign, namely activity enhancements and depressions, are correlated in time at least over a temporal  ... 
doi:10.1016/j.chaos.2013.06.003 fatcat:fplba676jndaphenfinv3hfy3i

The collective brain is critical [article]

Enzo Tagliazucchi, Dante R. Chialvo
2011 arXiv   pre-print
The unique dynamical features of the critical state endow the brain with properties which are fundamental for adaptive behavior.  ...  The rationale behind this program is discussed in these notes, followed by an account of the most recent results, together with a discussion of the physiological significance of these ideas.  ...  E.T. was supported by an Estímulo Fellowship from the University of Buenos Aires.  ... 
arXiv:1103.2070v1 fatcat:45t6qwkevrbbhpgasu6vottvzi

Fractals in the Nervous System: conceptual Implications for Theoretical Neuroscience [article]

Gerhard Werner
2010 arXiv   pre-print
This essay is presented with two principal objectives in mind: first, to document the prevalence of fractals at all levels of the nervous system, giving credence to the notion of their functional relevance  ...  The final Section consists of general reflections on the implications of the reviewed data, and identifies what appear to be issues of fundamental importance for future research in the rapidly evolving  ...  Differences between low frequency BOLD signal spectral power in task and rest periods also support the notion of fMRI reflecting meaningful brain states (Duff et al, 2008) , as do the emotional task dependent  ... 
arXiv:0910.2741v2 fatcat:nj6zeigotrdnrkaoivgcjxcuke

Systematic Review: Anesthetic Protocols and Management as Confounders in Rodent Blood Oxygen Level Dependent Functional Magnetic Resonance Imaging (BOLD fMRI)–Part B: Effects of Anesthetic Agents, Doses and Timing

Aline R. Steiner, Frédérik Rousseau-Blass, Aileen Schroeter, Sonja Hartnack, Regula Bettschart-Wolfensberger
2021 Animals  
In the present systematic review, literature analyzing in rats and mice the influence of anesthesia regimes and concurrent physiological functions on blood oxygen level dependent (BOLD) fMRI results was  ...  In rodent models the use of functional magnetic resonance imaging (fMRI) under anesthesia is common.  ...  Changes in the ratio of deoxy-to oxyhemoglobin content per unit of brain determine changes in BOLD signal.  ... 
doi:10.3390/ani11010199 pmid:33467584 pmcid:PMC7830239 fatcat:62cmzhi5cbap7m7h72kkvghaxm

Fractals in the nervous system: conceptual implications for theoretical neuroscience

Gerhard Werner
2010 Frontiers in Physiology  
This essay is presented with two principal objectives in mind: first, to document the prevalence of fractals at all levels of the nervous system, giving credence to the notion of their functional relevance  ...  The final Section consists of general reflections on the implications of the reviewed data, and identifies what appear to be issues of fundamental importance for future research in the rapidly evolving  ...  Differences between low frequency BOLD signal spectral power in task and rest periods also support the notion of fMRI reflecting meaningful brain states (Duff et al., 2008) , as do the emotional task-dependent  ... 
doi:10.3389/fphys.2010.00015 pmid:21423358 pmcid:PMC3059969 fatcat:qjhzo4ioarg35crh3eblkxfyiq
« Previous Showing results 1 — 15 out of 131 results