Robust controlled functional MRI in alert monkeys at high magnetic field: Effects of jaw and body movements

Keliris, Georgios A.; Shmuel, Amir; Ku, Shih-Pi; Pfeuffer, Josef; Oeltermann, A; Steudel, T; Logothetis, Nikos K.

doi:10.1016/j.neuroimage.2007.02.057

Cited by 40 publications

(57 citation statements)

References 32 publications

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“…More than that, we found that eyeball movements may induce artifacts into visual areas, which was not found in previous monkey tests [20] , but is consistent with some human studies [40,41] . A possible difference between our experiment and the tasks used in monkey studies is that monkeys were at least required to look at the fi xation point for a period of time, while in our experiment the cats were in a pure free-viewing condition.…”

Section: Discussionsupporting

confidence: 92%

“…An MRI-compatible head-post implanted on the skull is the most commonly used device for head fi xation [9,15,[17][18][19][20][21][22][23][24]26] . Although noninvasive methods have been proposed for monkey studies [27] , a plastic head-post is still the best choice if we are to extend fMRI experiments to cats, due to the complexity of the noninvasive methods.…”

Section: Discussionmentioning

confidence: 99%

“…It has previously been shown that limb and torso movements induce B0 fluctuations, resulting in spatial distortion [17] . To reduce jaw and body movement-induced artifacts in the fMRI time series, a novel training paradigm that allows monkeys to move their body between trials has proven successful [20] . However, it may take 6 months to train a monkey to remain still in the scanner [39] , and even longer for the animal to adapt to more sophisticated motion-control paradigms.…”

Section: Discussionmentioning

confidence: 99%

“…Most of the studies scanning behaving monkeys have developed similar methods [9,10,[14][15][16][17][18][19][20][21][22][23][24][25][26] . One of the most important aspects in the awake monkey fMRI scan is to keep the monkey's head in position by invasively implanting a headpost on the skull or by noninvasive techniques, such as a vacuum helmet [27] .…”

Section: Introductionmentioning

confidence: 99%

“…There is evidence that without proper training, non-rigid movements of the jaw and body induce artifacts into the BOLD signals recorded from the brain [20] due to fluctuations of the B0 field (the main magnetic field generated by the magnet). Motion-correction methods can help in the data analysis procedures; however, motion-correction algorithms sometimes introduce more artifacts under these conditions [17] .…”

mentioning

confidence: 99%

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Setup and data analysis for functional magnetic resonance imaging of awake cat visual cortex

Cui

et al. 2013

Neurosci. Bull.

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Functional magnetic resonance imaging (fMRI) is one of the most commonly used methods in cognitive neuroscience on humans. In recent decades, fMRI has also been used in the awake monkey experiments to localize functional brain areas and to compare the functional differences between human and monkey brains. Several procedures and paradigms have been developed to maintain proper head fixation and to perform motion control training. In this study, we extended the application of fMRI to awake cats without training, receiving a fl ickering checkerboard visual stimulus projected to a screen in front of them in a block-design paradigm. We found that body movement-induced non-rigid motion introduced artifacts into the functional scans, especially those around the eye and neck. To correct for these artifacts, we developed two methods: one for general experimental design, and the other for studies of whether a checkerboard task could be used as a localizer to optimize the motioncorrection parameters. The results demonstrated that, with proper animal fixation and motion correction procedures, it is possible to perform fMRI experiments with untrained awake cats.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Setup and data analysis for functional magnetic resonance imaging of awake cat visual cortex

Cui

et al. 2013

Neurosci. Bull.

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Phase informed model for motion and susceptibility

Hutton

Andersson

Deichmann

et al. 2012

Human Brain Mapping

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Field inhomogeneities caused by variations in magnetic susceptibility throughout the head lead to geometric distortions, mainly in the phase-encode direction of echo-planar images (EPI). The magnitude and spatial characteristics of the distortions depend on the orientation of the head in the magnetic field and will therefore vary with head movement. A new method is presented, based on a phase informed model for motion and susceptibility (PIMMS), which estimates the change in geometric distortion associated with head motion. This method fits a model of the head motion parameters and scanner hardware characteristics to EPI phase time series. The resulting maps of the model fit parameters are used to correct for susceptibility artifacts in the magnitude images. Results are shown for EPI-based fMRI time-series acquired at 3T, demonstrating that compared with conventional rigid body realignment, PIMMS removes residual variance associated with motion-related distortion effects. Furthermore, PIMMS can lead to a reduction in false negatives compared with the widely accepted approach which uses standard rigid body realignment and includes the head motion parameters in the statistical model. The PIMMS method can be used with any standard EPI sequence for which accurate phase information is available. Hum Brain Mapp 34:3086-3100,

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