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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Elsevier
2021
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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) |
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DOAJ |
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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 |
work_keys_str_mv |
AT anqiwu brainkernelanewspatialcovariancefunctionforfmridata AT samuelanastase brainkernelanewspatialcovariancefunctionforfmridata AT christopherabaldassano brainkernelanewspatialcovariancefunctionforfmridata AT nicholasbturkbrowne brainkernelanewspatialcovariancefunctionforfmridata AT kennethanorman brainkernelanewspatialcovariancefunctionforfmridata AT barbaraeengelhardt brainkernelanewspatialcovariancefunctionforfmridata AT jonathanwpillow brainkernelanewspatialcovariancefunctionforfmridata |
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1718440663943479296 |