1,213 Hits in 9.0 sec

Low-frequency fluctuations in the cardiac rate as a source of variance in the resting-state fMRI BOLD signal

Karin Shmueli, Peter van Gelderen, Jacco A. de Zwart, Silvina G. Horovitz, Masaki Fukunaga, J. Martijn Jansma, Jeff H. Duyn
2007 NeuroImage  
Heart rate fluctuations occur in the low-frequency range (b0.1 Hz) probed in functional magnetic resonance imaging (fMRI) studies of resting-state functional connectivity and most fMRI block paradigms  ...  Regressors consisting of cardiac rate timecourses shifted by delays of between 0 and 24 s explained an additional 1% of the BOLD signal variance on average over the whole brain across 9 subjects, a similar  ...  Acknowledgments This research was supported by the Intramural Research Program of the National Institute of Neurological Disorders and Stroke, National Institutes of Health.  ... 
doi:10.1016/j.neuroimage.2007.07.037 pmid:17869543 pmcid:PMC2128785 fatcat:usyjjfajdnfcfomgdxmmgn6nji

Sources of functional magnetic resonance imaging signal fluctuations in the human brain at rest: a 7 T study

Marta Bianciardi, Masaki Fukunaga, Peter van Gelderen, Silvina G. Horovitz, Jacco A. de Zwart, Karin Shmueli, Jeff H. Duyn
2009 Magnetic Resonance Imaging  
We suggest the selection and use of four lagged physiological noise regressors as an effective model to explain the variance related to fluctuations in the rate of respiration volume change and cardiac  ...  The following sources of variance were evaluated separately: low frequency drifts due to scanner instability, effects correlated with respiratory and cardiac cycles, effects due to variability in the respiratory  ...  Acknowledgments This research was supported by the Intramural Research Program of the National Institutes of Health, National Institutes of Neurological Disorders and Stroke. We thank Alan P.  ... 
doi:10.1016/j.mri.2009.02.004 pmid:19375260 pmcid:PMC3512098 fatcat:qy76sagjrrffvpl6xxa3777auu

The relationship between BOLD signal and autonomic nervous system functions: implications for processing of "physiological noise"

Vittorio Iacovella, Uri Hasson
2011 Magnetic Resonance Imaging  
On the other hand, a different line of work has made important progress in showing that ANS functions such as cardiac pulsation, heart rate variability and breathing rate could be considered as a theoretically  ...  brain states as measured in the human brain.  ...  This suggests that, when analyzing BOLD signal fluctuations in this frequency band, ANS influences could be considered as a significant source of fluctuations.  ... 
doi:10.1016/j.mri.2011.03.006 pmid:21543181 fatcat:et3ym6jgb5c3hg77wbvyb6jega

Physiological denoising of BOLD fMRI data using Regressor Interpolation at Progressive Time Delays (RIPTiDe) processing of concurrent fMRI and near-infrared spectroscopy (NIRS)

Blaise deB. Frederick, Lisa D. Nickerson, Yunjie Tong
2012 NeuroImage  
Cardiac noise is particularly problematic, as the low sampling frequency of BOLD fMRI ensures that these effects are aliased in recorded data.  ...  Confounding noise in BOLD fMRI data arises primarily from fluctuations in blood flow and oxygenation due to cardiac and respiratory effects, spontaneous low frequency oscillations (LFO) in arterial pressure  ...  Acknowledgments This work was supported by the National Institutes of Health, Grant Nos. R21-DA021817 and R21-DA027877.  ... 
doi:10.1016/j.neuroimage.2012.01.140 pmid:22342801 pmcid:PMC3593078 fatcat:7y24wwlyqvdiplozrsrepqq53i

Impact of physiological noise correction on detecting blood oxygenation level-dependent contrast in the breast

Tess E Wallace, Roido Manavaki, Martin J Graves, Andrew J Patterson, Fiona J Gilbert
2016 Physics in Medicine and Biology  
the detection of BOLD contrast in the breast in response to a modulated respiratory stimulus.  ...  Abstract Physiological fluctuations are expected to be a dominant source of noise in blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) experiments to assess tumour oxygenation and  ...  Acknowledgments This work was supported by the NIHR Cambridge Biomedical Research Centre, the Cambridge Experimental Cancer Medicine Centre and the CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester  ... 
doi:10.1088/1361-6560/62/1/127 pmid:27973353 pmcid:PMC6050521 fatcat:obqhatsxljcwbgk5dvaba42afq

Sensitivity of the resting-state haemodynamic response function estimation to autonomic nervous system fluctuations

Guo-Rong Wu, Daniele Marinazzo
2016 Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences  
In this study we compare the resting state hemodynamic response retrieved by means of a point process analysis taking the cardiac fluctuations into account.  ...  durations are associated with the mean inter-beat interval and low frequency power of heart rate variability in the brainstem.  ...  However, it only filters cyclic effects aliased in the fMRI signal, while the physiology-related low-frequency fluctuations remain in the data.  ... 
doi:10.1098/rsta.2015.0190 pmid:27044997 pmcid:PMC4822449 fatcat:7qg3fjj3pzcwpj5hgt5772mnxa

Physiological origin of low-frequency drift in blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI)

Lirong Yan, Yan Zhuo, Yongquan Ye, Sharon X. Xie, Jing An, Geoffrey K. Aguirre, Jiongjiong Wang
2009 Magnetic Resonance in Medicine  
Our study supports brain physiology, as opposed to scanner instabilities or cardiac/respiratory pulsations, as the main source of low-frequency drifts in BOLD fMRI. Magn Reson Med 61:819 -827, 2009.  ...  We further demonstrated that intrinsic, physiological drift effects are a major component of the spontaneous fluctuations of BOLD fMRI signal within the frequency range of 0.0 -0.1 Hz.  ...  BOLD fMRI signals share a metabolic and physiologic source.  ... 
doi:10.1002/mrm.21902 pmid:19189286 fatcat:qfyg5qrbqng4lg3drj4gzso7ha

Methods for cleaning the BOLD fMRI signal

César Caballero-Gaudes, Richard C. Reynolds
2017 NeuroImage  
Through the review, we summarize the importance of signal denoising as an essential step in the analysis pipeline of task-based and resting state fMRI studies.  ...  This review aims to provide a comprehensive summary of existing methods for cleaning the BOLD fMRI signal.  ...  in R & D [SEV-2015-490], and the research and writing of the paper were supported by the NIMH and NINDS Intramural Research Programs (ZICMH002888) of the NIH/HHS.  ... 
doi:10.1016/j.neuroimage.2016.12.018 pmid:27956209 pmcid:PMC5466511 fatcat:nexqgsdfmvd73grkzcfnrkhesm

Beyond Noise: Using Temporal ICA to Extract Meaningful Information from High-Frequency fMRI Signal Fluctuations during Rest

Roland N. Boubela, Klaudius Kalcher, Wolfgang Huf, Claudia Kronnerwetter, Peter Filzmoser, Ewald Moser
2013 Frontiers in Human Neuroscience  
Analysis of resting-state networks using fMRI usually ignores high-frequency fluctuations in the BOLD signal -be it because of low TR prohibiting the analysis of fluctuations with frequencies higher than  ...  While the standard model of convolving neuronal activity with a hemodynamic response function suggests that the signal of interest in fMRI is characterized by slow fluctuation, it is in fact unclear whether  ...  The authors are grateful to Lucie Bartova and Lukas Pezawas for managing the subject recruiting process, and to Georg Rath for technical support.  ... 
doi:10.3389/fnhum.2013.00168 pmid:23641208 pmcid:PMC3640215 fatcat:ojj5c5ps7rcdblf3vtpid3uywi

The power of spectral density analysis for mapping endogenous BOLD signal fluctuations

Eugene P. Duff, Leigh A. Johnston, Jinhu Xiong, Peter T. Fox, Iven Mareels, Gary F. Egan
2008 Human Brain Mapping  
In conclusion, analysis of PSD is a sensitive method for detecting and characterizing BOLD signal oscillations that can enhance the analysis of network connectivity.  ...  FMRI has revealed the presence of correlated low-frequency cerebro-vascular oscillations within functional brain systems, which are thought to reflect an intrinsic feature of large-scale neural activity  ...  Acknowledgments We thank the reviewers for their comments.  ... 
doi:10.1002/hbm.20601 pmid:18454458 pmcid:PMC5441229 fatcat:xqvzeo7warc5nnwyxyo2bhsvau

Investigation of BOLD fMRI resonance frequency shifts and quantitative susceptibility changes at 7 T

Marta Bianciardi, Peter van Gelderen, Jeff H. Duyn
2013 Human Brain Mapping  
Although blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) experiments of brain activity generally rely on the magnitude of the signal, they also provide frequency information  ...  Keywords BOLD fMRI phase signal changes; BOLD fMRI resonance frequency shifts; BOLD fMRI quantitative susceptibility changes; fractional oxygen saturation  ...  Contract grant sponsor: Intramural Research Program of the National Institutes of Health; Contract grant sponsor: National Institute of Neurological Disorders and Stroke.  ... 
doi:10.1002/hbm.22320 pmid:23897623 pmcid:PMC4280841 fatcat:varkuuodinb4hhtmamsrgkxz2y

Hemodynamic response function in resting brain: disambiguating neural events and autonomic effects [article]

Guorong Wu, Daniele Marinazzo
2015 bioRxiv   pre-print
Cardiac activity can also induce changes in the BOLD signal, thus affect both the number of these events and the mapping between neural events and BOLD signal, namely the hemodynamic response.  ...  To isolate neural activity and autonomic effects, we compare the resting state hemodynamic response retrieved by means of a point process analysis with and without deconvolving the cardiac fluctuations  ...  However, it only filters cardiac cyclic effects aliased in the fMRI signal, while the cardiac-related low-frequency fluctuations remain in the data.  ... 
doi:10.1101/028514 fatcat:pshi5i2nanbklnkn44c55qpp6a

Physiological noise modeling in fMRI based on the pulsatile component of photoplethysmograph

Michalis Kassinopoulos, Georgios D. Mitsis
2021 NeuroImage  
Further, we investigate whether variations in the amplitude of the PPG pulses (PPG-Amp) covary with variations in amplitude of pulse-related fMRI fluctuations, as well as with the systemic low frequency  ...  The amplitude of the fMRI pulse-related fluctuations did not covary with PPG-Amp; however, PPG-Amp explained significant variance in the GS that was not attributed to variations in heart rate or breathing  ...  Overall, the pulsatile component of the PPG signal was found to explain a large fraction of variance in fMRI related to both low-and high-frequency physiological fluctuations.  ... 
doi:10.1016/j.neuroimage.2021.118467 pmid:34390877 fatcat:s5mtdu7mc5el3f6qxmt3wcsqey

Resting fluctuations in arterial carbon dioxide induce significant low frequency variations in BOLD signal

Richard G Wise, Kojiro Ide, Marc J Poulin, Irene Tracey
2004 NeuroImage  
(IT) and the Alberta Heritage Foundation for Medical Research (AHFMR), the Canadian Institutes of Health Research (CIHR) and the Heart and Stroke Foundation of Alberta, NWT and Nunavut.  ...  MJP is a CIHR New Investigator and AHFMR Medical Scholar. KI is a AHFMR postdoctoral fellow.  ...  A component of the low-frequency fluctuations in the BOLD signal has been ascribed to changes in neuronal activity in functionally connected regions, often termed resting state networks (Biswal et al.  ... 
doi:10.1016/j.neuroimage.2003.11.025 pmid:15050588 fatcat:p36yzup4rvfgdgpeaahrhtlivy

Low Frequency Systemic Hemodynamic "Noise" in Resting State BOLD fMRI: Characteristics, Causes, Implications, Mitigation Strategies, and Applications

Yunjie Tong, Lia M. Hocke, Blaise B. Frederick
2019 Frontiers in Neuroscience  
Advances in functional magnetic resonance imaging (fMRI) acquisition have improved signal to noise to the point where the physiology of the subject is the dominant noise source in resting state fMRI data  ...  Among these systemic, non-neuronal physiological signals, respiration and to some degree cardiac fluctuations can be removed through modeling, or in the case of newer, faster acquisitions such as simultaneous  ...  AUTHOR CONTRIBUTIONS All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.  ... 
doi:10.3389/fnins.2019.00787 pmid:31474815 pmcid:PMC6702789 fatcat:rup7ygtqava6los7hy2vwyaxaa
« Previous Showing results 1 — 15 out of 1,213 results