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      Movement-Related effects in fMRI time-series

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          Abstract

          This paper concerns the spatial and intensity transformations that are required to adjust for the confounding effects of subject movement during functional MRI (fMRI) activation studies. An approach is presented that models, and removes, movement-related artifacts from fMRI time-series. This approach is predicated on the observation that movement-related effects are extant even after perfect realignment. Movement-related effects can be divided into those that are a function of position of the object in the frame of reference of the scanner and those that are due to movement in previous scans. This second component depends on the history of excitation experienced by spins in a small volume and consequent differences in local saturation. The spin excitation history thus will itself be a function of previous positions, suggesting an autoregression-moving average model for the effects of previous displacements on the current signal. A model is described as well as the adjustments for movement-related components that ensue. The empirical analyses suggest that (in extreme situations) over 90% of fMRI signal can be attributed to movement, and that this artifactual component can be successfully removed.

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          Most cited references3

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          Spatial registration and normalization of images

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            Artifacts due to stimulus correlated motion in functional imaging of the brain.

            To assess the effect of stimulus correlated motion on the appearance of functional magnetic resonance images, conventional visual and motor protocols were each performed by four normal volunteers and an image co-registration technique was used to retrospectively monitor subject motion. In three studies synthetic data sets were constructed from single baseline images using the positional information obtained from the co-registration procedure. Cumulative difference images were then created from both the synthetic and functional image sets. Stimulus correlated motion was detected in all eight studies and the synthetic cumulative difference images showed striking similarities to the equivalent functional images in each case.
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              • Record: found
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              Some computational and statistical tools for paired comparisons of digital images

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                Author and article information

                Journal
                Magnetic Resonance in Medicine
                Magn. Reson. Med.
                Wiley
                07403194
                March 1996
                March 1996
                February 03 2011
                : 35
                : 3
                : 346-355
                Article
                10.1002/mrm.1910350312
                8699946
                6f2cc84d-5416-4c3f-8176-dfe96d579587
                © 2011

                http://doi.wiley.com/10.1002/tdm_license_1.1

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