Brain kernel: A new spatial covariance function for fMRI data

A key problem in functional magnetic resonance imaging (fMRI) is to estimate spatial activity patterns from noisy high-dimensional signals. Spatial smoothing provides one approach to regularizing such estimates. However, standard smoothing methods ignore the fact that correlations in neural activity...

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Autores principales: Anqi Wu, Samuel A. Nastase, Christopher A. Baldassano, Nicholas B. Turk-Browne, Kenneth A. Norman, Barbara E. Engelhardt, Jonathan W. Pillow
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Lenguaje:EN
Publicado: Elsevier 2021
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Acceso en línea:https://doaj.org/article/7953409cdc8143cca57ed3d4ffd1a406
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spelling oai:doaj.org-article:7953409cdc8143cca57ed3d4ffd1a4062021-11-10T04:21:08ZBrain kernel: A new spatial covariance function for fMRI data1095-957210.1016/j.neuroimage.2021.118580https://doaj.org/article/7953409cdc8143cca57ed3d4ffd1a4062021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S1053811921008533https://doaj.org/toc/1095-9572A key problem in functional magnetic resonance imaging (fMRI) is to estimate spatial activity patterns from noisy high-dimensional signals. Spatial smoothing provides one approach to regularizing such estimates. However, standard smoothing methods ignore the fact that correlations in neural activity may fall off at different rates in different brain areas, or exhibit discontinuities across anatomical or functional boundaries. Moreover, such methods do not exploit the fact that widely separated brain regions may exhibit strong correlations due to bilateral symmetry or the network organization of brain regions. To capture this non-stationary spatial correlation structure, we introduce the brain kernel, a continuous covariance function for whole-brain activity patterns. We define the brain kernel in terms of a continuous nonlinear mapping from 3D brain coordinates to a latent embedding space, parametrized with a Gaussian process (GP). The brain kernel specifies the prior covariance between voxels as a function of the distance between their locations in embedding space. The GP mapping warps the brain nonlinearly so that highly correlated voxels are close together in latent space, and uncorrelated voxels are far apart. We estimate the brain kernel using resting-state fMRI data, and we develop an exact, scalable inference method based on block coordinate descent to overcome the challenges of high dimensionality (10-100K voxels). Finally, we illustrate the brain kernel’s usefulness with applications to brain decoding and factor analysis with multiple task-based fMRI datasets.Anqi WuSamuel A. NastaseChristopher A. BaldassanoNicholas B. Turk-BrowneKenneth A. NormanBarbara E. EngelhardtJonathan W. PillowElsevierarticleBrain kernelGaussian processLatent variable modelBrain decodingFactor modelingResting-state fmriNeurosciences. Biological psychiatry. NeuropsychiatryRC321-571ENNeuroImage, Vol 245, Iss , Pp 118580- (2021)
institution DOAJ
collection DOAJ
language EN
topic Brain kernel
Gaussian process
Latent variable model
Brain decoding
Factor modeling
Resting-state fmri
Neurosciences. Biological psychiatry. Neuropsychiatry
RC321-571
spellingShingle Brain kernel
Gaussian process
Latent variable model
Brain decoding
Factor modeling
Resting-state fmri
Neurosciences. Biological psychiatry. Neuropsychiatry
RC321-571
Anqi Wu
Samuel A. Nastase
Christopher A. Baldassano
Nicholas B. Turk-Browne
Kenneth A. Norman
Barbara E. Engelhardt
Jonathan W. Pillow
Brain kernel: A new spatial covariance function for fMRI data
description A key problem in functional magnetic resonance imaging (fMRI) is to estimate spatial activity patterns from noisy high-dimensional signals. Spatial smoothing provides one approach to regularizing such estimates. However, standard smoothing methods ignore the fact that correlations in neural activity may fall off at different rates in different brain areas, or exhibit discontinuities across anatomical or functional boundaries. Moreover, such methods do not exploit the fact that widely separated brain regions may exhibit strong correlations due to bilateral symmetry or the network organization of brain regions. To capture this non-stationary spatial correlation structure, we introduce the brain kernel, a continuous covariance function for whole-brain activity patterns. We define the brain kernel in terms of a continuous nonlinear mapping from 3D brain coordinates to a latent embedding space, parametrized with a Gaussian process (GP). The brain kernel specifies the prior covariance between voxels as a function of the distance between their locations in embedding space. The GP mapping warps the brain nonlinearly so that highly correlated voxels are close together in latent space, and uncorrelated voxels are far apart. We estimate the brain kernel using resting-state fMRI data, and we develop an exact, scalable inference method based on block coordinate descent to overcome the challenges of high dimensionality (10-100K voxels). Finally, we illustrate the brain kernel’s usefulness with applications to brain decoding and factor analysis with multiple task-based fMRI datasets.
format article
author Anqi Wu
Samuel A. Nastase
Christopher A. Baldassano
Nicholas B. Turk-Browne
Kenneth A. Norman
Barbara E. Engelhardt
Jonathan W. Pillow
author_facet Anqi Wu
Samuel A. Nastase
Christopher A. Baldassano
Nicholas B. Turk-Browne
Kenneth A. Norman
Barbara E. Engelhardt
Jonathan W. Pillow
author_sort Anqi Wu
title Brain kernel: A new spatial covariance function for fMRI data
title_short Brain kernel: A new spatial covariance function for fMRI data
title_full Brain kernel: A new spatial covariance function for fMRI data
title_fullStr Brain kernel: A new spatial covariance function for fMRI data
title_full_unstemmed Brain kernel: A new spatial covariance function for fMRI data
title_sort brain kernel: a new spatial covariance function for fmri data
publisher Elsevier
publishDate 2021
url https://doaj.org/article/7953409cdc8143cca57ed3d4ffd1a406
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