Filters








167 Hits in 9.0 sec

Intracortical smoothing of small-voxel fMRI data can provide increased detection power without spatial resolution losses compared to conventional large-voxel fMRI data

Anna Blazejewska, Bruce Fischl, Lawrence L. Wald, Jonathan R. Polimeni
2019 NeuroImage  
of both detection power and spatial resolution) compared to an unsmoothed 3.0-mm isotropic fMRI acquisition.  ...  higher detection power and higher resolution than conventional voxel sizes.  ...  Additional support was provided by the NIH Blueprint for Neuroscience Research (U01-MH093765), part of the multi-institutional Human Connectome Project.  ... 
doi:10.1016/j.neuroimage.2019.01.054 pmid:30690157 pmcid:PMC6668026 fatcat:uhlkrtqohfh7rlutxtrjsynn5a

Analysis strategies for high-resolution UHF-fMRI data

Jonathan R. Polimeni, Ville Renvall, Natalia Zaretskaya, Bruce Fischl
2018 NeuroImage  
These include strategies designed to mitigate distortion and artifacts associated with higher fields in ways that attempt to preserve spatial resolution of the fMRI data, as well as recently introduced  ...  Most UHF-fMRI studies utilize the dramatic increases in sensitivity and specificity to acquire high-resolution data reaching sub-millimeter scales, which enable new classes of experiments to probe the  ...  Additional support was provided by the NIH Blueprint for Neuroscience Research (U01-MH093765), part of the multi-institutional Human Connectome Project.  ... 
doi:10.1016/j.neuroimage.2017.04.053 pmid:28461062 pmcid:PMC5664177 fatcat:dcrrvh4sgfcb5diw62bgbeng2a

Functional quantitative susceptibility mapping (fQSM)

Dávid Z. Balla, Rosa M. Sanchez-Panchuelo, Samuel J. Wharton, Gisela E. Hagberg, Klaus Scheffler, Susan T. Francis, Richard Bowtell
2014 NeuroImage  
Several fQSM pipelines were evaluated and compared based on the relative number of voxels that were coincidentally found to be significant in QSM and magnitude SPMs (common voxels).  ...  Several fQSM pipelines were evaluated and compared based on the relative number of voxels that were coincidentally found to be significant in QSM and magnitude SPMs (common voxels).  ...  Both the number of activated voxels and the number of common voxels increased significantly when the fMRI data were spatially smoothed before the GLM fit (Balla et al., 2012) .  ... 
doi:10.1016/j.neuroimage.2014.06.011 pmid:24945672 fatcat:55xe65or2vbojnom23adwzugxu

Comparing Like with Like: The Power of Knowing Where You Are

Robert Turner, Stefan Geyer
2014 Brain Connectivity  
These improvements throw into sharp question the strategies that have become conventional for the analysis of functional imaging data, especially the practice of spatial smoothing of raw functional data  ...  Magnetic resonance imaging can now provide human brain images of structure, function, and connectivity with isotropic voxels smaller than one millimeter, and thus much smaller than the cortical thickness  ...  The appearance of simplicity provided by spatial smoothing and conservative thresholding of fMRI data may be highly misleading.  ... 
doi:10.1089/brain.2014.0261 pmid:24999746 pmcid:PMC4146387 fatcat:2uzizewjfbgftlox6u77ajceui

How does an fMRI voxel sample the neuronal activity pattern: Compact-kernel or complex spatiotemporal filter?

Nikolaus Kriegeskorte, Rhodri Cusack, Peter Bandettini
2010 NeuroImage  
Recent studies suggested that fMRI voxel patterns can convey information represented in columnar-scale neuronal population codes, even when spatial resolution is insufficient to directly image the patterns  ...  Importantly, the complex-spatiotemporal-filter hypothesis of fMRI hyperacuity can account for the observed robustness to slight shifts of the voxel grid caused by head motion: Because the fine-grained  ...  Acknowledgment The authors thank Kendrick Kay for helpful comments on a draft of this paper.  ... 
doi:10.1016/j.neuroimage.2009.09.059 pmid:19800408 pmcid:PMC2818340 fatcat:k5u22e3avvhm3bcbnibsqolssu

Multishot versus Single-Shot Pulse Sequences in Very High Field fMRI: A Comparison Using Retinotopic Mapping

Jascha D. Swisher, John A. Sexton, J. Christopher Gatenby, John C. Gore, Frank Tong, Hans P. Op de Beeck
2012 PLoS ONE  
Here we consider retinotopic mapping of human visual cortex as a practical test case by which to compare examples of these sequence types for high-resolution fMRI at 7 Tesla.  ...  Though higher field strengths promise improvements in signal-to-noise ratios (SNR) and BOLD contrast relative to fMRI at 3 Tesla, these benefits may be partially offset by accompanying increases in geometric  ...  Acknowledgments The authors wish to acknowledge Peter Koopmans for many helpful discussions, Ryan Robison for assistance with pulse sequences, and the useful comments of the anonymous reviewers of this  ... 
doi:10.1371/journal.pone.0034626 pmid:22514646 pmcid:PMC3326057 fatcat:rpfux7boirandmmqterda62xza

A critical assessment of data quality and venous effects in ultra-high-resolution fMRI [article]

Kendrick Kay, Keith Jamison, Luca Vizioli, Ruyuan Zhang, Eshed Margalit, Kamil Ugurbil
2018 bioRxiv   pre-print
tools to assess the quality of the data.  ...  Second, we show that the highly folded structure of cortex causes substantial biases on spatial resolution and data visualization.  ...  Masking out voxels near veins (Koopmans et al., 2010; Moerel et 13 al., 2018; Shmuel et al., 2007) can be helpful, but small veins occupying a fraction of the voxel volume will 14 not be detected by this  ... 
doi:10.1101/337667 fatcat:eroz2mcuejc5lgzke6fybhslo4

Magnetic Resonance Imaging at Ultrahigh Fields

Kamil Ugurbil
2014 IEEE Transactions on Biomedical Engineering  
However, they are advantageous for parallel imaging for signal reception and parallel transmission, two critical technologies that account, to a large extend, for the success of ultrahigh fields.  ...  With these technologies, and improvements in instrumentation and imaging methods, ultrahigh fields have provided unprecedented gains in imaging of brain function and anatomy, and started to make inroads  ...  of the National Institutes of Health that support the NIH Blueprint for Neuroscience Research, and P30 NS076408.  ... 
doi:10.1109/tbme.2014.2313619 pmid:24686229 pmcid:PMC4135536 fatcat:qi7mqp5mavff7gpru2jmv7mx4i

Techniques for blood volume fMRI with VASO: From low-resolution mapping towards sub-millimeter layer-dependent applications

Laurentius Huber, Dimo Ivanov, Daniel A. Handwerker, Sean Marrett, Maria Guidi, Kâmil Uludağ, Peter A. Bandettini, Benedikt A. Poser
2018 NeuroImage  
Techniques for blood volume fMRI with VASO: From low-resolution mapping towards sub-millimeter layerdependent applications. Neuroimage, 164, 131-143. https://doi.  ...  high-32 resolution fMRI data: The achievable resolution and voxel size of the fMRI acquisition is not only 8 limited by the amount of MRI signal available to detect functional activations in 9 the  ...  In the thermal-noise-dominated regime of sub- 6 millimeter resolutions, 3D-segmented-EPI-VASO provides higher temporal stability and 7 sensitivity to detect changes in CBV compared to 2D-EPI-VASO.  ... 
doi:10.1016/j.neuroimage.2016.11.039 pmid:27867088 pmcid:PMC5436958 fatcat:fg5n2cnoybdolilw4jpbhflduu

Imaging at ultrahigh magnetic fields: History, challenges, and solutions

Kamil Uğurbil
2018 NeuroImage  
However, they are advantageous for parallel imaging in signal reception and transmission, two critical technologies that account, to a large extend, for the success of ultrahigh fields.  ...  Work conducted on these platforms has provided numerous technological solutions to challenges posed at these ultrahigh fields, and demonstrated the existence of significant advantages in signal-to-noise  ...  the need for spatial smoothing, at nominal voxel volumes as small as 1 mm 3 (isotropic voxel dimension), significantly smaller than the voxel sizes employed at 3 T.  ... 
doi:10.1016/j.neuroimage.2017.07.007 pmid:28698108 pmcid:PMC5758441 fatcat:xuo6bzgoq5bznleo3g4xna4wci

Ultra-high resolution blood volume fMRI and BOLD fMRI in humans at 9.4 T: Capabilities and challenges

Laurentius Huber, Desmond H.Y. Tse, Christopher J. Wiggins, Kâmil Uludağ, Sriranga Kashyap, David C. Jangraw, Peter A. Bandettini, Benedikt A. Poser, Dimo Ivanov
2018 NeuroImage  
We found that a combination of suitable advanced methodology alleviates the challenges and potential artifacts, and that VASO fMRI provides reliable measures of CBV change across cortical layers in humans  ...  Functional mapping of cerebral blood volume (CBV) changes has the potential to reveal brain activity with high localization specificity at the level of cortical layers and columns.  ...  We acknowledge Markus Barth for contributions to early versions of the 3D-EPI sequence. We thank Scannexus for the friendly scanning environment.  ... 
doi:10.1016/j.neuroimage.2018.06.025 pmid:29890330 pmcid:PMC6100753 fatcat:ogjry2gc3ngxhh5l4dmerfkxja

Hemodynamic scaling of fMRI-BOLD signal: validation of low-frequency spectral amplitude as a scalability factor

Bharat B. Biswal, Sridhar S. Kannurpatti, Bart Rypma
2007 Magnetic Resonance Imaging  
LFSA free from motor-task contamination can be used to calibrate the fMRI-BOLD response in lieu of BHA or hypercapnia to minimize intra-and intersubject variation arising from vascular anatomy and vasodilative  ...  The objective of this study was to reduce the hemodynamic change independent of neural activity to obtain a scaled fMRI-BOLD response using two factors, namely, low-frequency spectral amplitude (LFSA)  ...  The authors would like to thank the anonymous reviewers for their valuable comments.  ... 
doi:10.1016/j.mri.2007.03.022 pmid:17482411 pmcid:PMC2701471 fatcat:ngz37425wbai5e67zzj6ofuhgy

Magnetic Resonance Imaging technology — bridging the gap between noninvasive human imaging and optical microscopy

Jonathan R Polimeni, Lawrence L Wald
2018 Current Opinion in Neurobiology  
While sensitivity increases are a necessary component, new MR encoding technologies are required to convert improved sensitivity into higher resolution.  ...  Technological advances in Magnetic Resonance Imaging (MRI) have provided substantial gains in the sensitivity and specificity of functional neuroimaging.  ...  This further spreads out aliasing in multiple directions to provide increased imaging performance, providing over an order of magnitude speed-up compared to conventional acquisitions [57,58].  ... 
doi:10.1016/j.conb.2018.04.026 pmid:29753942 pmcid:PMC6015259 fatcat:7msf5i7k5ja3tpavexhuzlw7wu

Laminar-specific interhemispheric connectivity mapping with bilateral line-scanning fMRI [article]

Sangcheon Choi, Yi Chen, Hang Zeng, Bharat Biswal, Xin Yu
2021 bioRxiv   pre-print
To address this question, we have developed a bilateral line-scanning fMRI (BiLS) method to detect bilateral laminar BOLD fMRI signals from symmetric cortical regions with high spatial (100 μm) and temporal  ...  Despite extensive studies detecting blood-oxygen-level-dependent (BOLD) fMRI signals across two hemispheres to present cognitive processes in normal and diseased brains, the role of corpus callosum (CC  ...  Blazejewska, A.I., et al., Intracortical smoothing of small-voxel fMRI data can provide increased detection 459 power without spatial resolution losses compared to conventional large-voxel fMRI data.  ... 
doi:10.1101/2021.03.08.433876 fatcat:fqkmys5gffblljp7hxic6cddo4

The minimal preprocessing pipelines for the Human Connectome Project

Matthew F. Glasser, Stamatios N. Sotiropoulos, J. Anthony Wilson, Timothy S. Coalson, Bruce Fischl, Jesper L. Andersson, Junqian Xu, Saad Jbabdi, Matthew Webster, Jonathan R. Polimeni, David C. Van Essen, Mark Jenkinson
2013 NeuroImage  
The MRI data acquired by the HCP differ in many ways from data acquired on conventional 3 Tesla scanners and often require newly developed preprocessing methods.  ...  These pipelines are specially designed to capitalize on the high quality data offered by the HCP.  ...  Additional support was provided by The Autism & Dyslexia Project funded by the Ellison Medical Foundation, and by the NIH Blueprint for Neuroscience Research (5U01-MH093765), part of the multiinstitutional  ... 
doi:10.1016/j.neuroimage.2013.04.127 pmid:23668970 pmcid:PMC3720813 fatcat:odadekdvwzakxlxc4u24smozp4
« Previous Showing results 1 — 15 out of 167 results