Chad Moritz - Academia.edu (original) (raw)

Papers by Chad Moritz

American Journal of Neuroradiology, 2003

Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the ... more Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the hemispheres. This synchrony implies neuronal connections between brain regions. The synchrony of blood flow changes is defined operationally as functional connectivity. Our purpose was to measure functional connectivity in patients with corpus callosal agenesis, in whom the interhemispheric connectivity is hypothetically diminished. In three patients with agenesis of the corpus callosum, functional MR imaging was performed while patients performed text-listening and finger-tapping tasks. Functional images were also acquired while the patients performed no specific task (resting state). Regions of activation temporally correlated with the performance of the tasks were identified by cross-correlating the task data with a reference function. Voxel clusters (seed voxels) that corresponded to regions of activation in the task-activation data set were selected in the resting data set. All the ...

Human Brain Mapping, 2003

Independent component analysis (ICA) has been demonstrated to be an effective data-driven method ... more Independent component analysis (ICA) has been demonstrated to be an effective data-driven method for analyzing fMRI data. However, a method for objective differentiation of task-related components from those that are artifactually non-relevant is needed. We propose a method of constant-cycle (periodic) fMRI task paradigm combined with ranking of spatial ICA components by the magnitude contribution of their temporal aspects to the fundamental task frequency. Power spectrum ranking shares some similarity to correlation with an a priori hemodynamic response, but without a need to presume an exact timing or duration of the fMRI response. When applied to a complex motor task paradigm with auditory cues, multiple task-related activations are successfully identified and separated from artifactual components. These activations include sensorimotor, auditory, and superior parietal areas. Comparisons of task-related component time courses indicate the temporal relationship of fMRI responses in functionally involved regions. Results indicate the sensitivity of ICA to short-duration hemodynamics, and the efficacy of a power spectrum ranking method for identification of task-related components.

Neurosurgical Focus, 2013

Object Functional MRI (fMRI) has proven to be an effective component of pretreatment planning in ... more Object Functional MRI (fMRI) has proven to be an effective component of pretreatment planning in patients harboring a variety of different brain lesions. The authors have recently reported significant relationships concerning distances between brain tumor borders and areas of functional activation (lesion-to-activation distance; LAD) with regard to patient morbidity and mortality. This study further examines the relationship between LAD, focusing on a host of vascular lesions and pre- and posttreatment morbidity. Methods This study included a sample population of patients with vascular lesions (n = 106), primarily arteriovenous malformations (AVMs) and cavernomas. These patients underwent pretreatment fMRI-based motor mapping (n = 72) or language mapping (n = 84). The impact of LAD and other variables derived from the patient medical record were analyzed with respect to functional deficits in terms of morbidity (weakness and/or aphasia). Results In patients with no pretreatment defi...

Background and Purpose—Functional magnetic resonance imaging (fMRI) has proven to be an effective... more Background and Purpose—Functional magnetic resonance imaging (fMRI) has proven to be an effective component of pretreatment planning in patients harboring a variety of different brain lesions. Our group has recently reported significant relationships concerning distances between brain tumor border and area of functional activation (Lesion-to-Activation-Distance; LAD) with regard to patient morbidity and mortality. This study further examines the relationship between LAD, focusing on a host of vascular lesions, and preand posttreatment morbidity. Materials and Methods—This study included a sample population (n=106) of patients with vascular lesions, primarily arteriovenous malformations (AVM) and cavernomas. These patients underwent pretreatment fMRI-based motor mapping (n=72) or language mapping (n=84). The impact of LAD and other variables derived from the patient medical record were analyzed with respect to functional deficits in terms of morbidity (weakness and/or aphasia). Resul...

BACKGROUND AND PURPOSE Regional cerebral blood flow fluctuates synchronously in corresponding bra... more BACKGROUND AND PURPOSE Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the hemispheres. This synchrony implies neuronal connections between brain regions. The synchrony of blood flow changes is defined operationally as functional connectivity. Our purpose was to measure functional connectivity in patients with corpus callosal agenesis, in whom the interhemispheric connectivity is hypothetically diminished. METHODS In three patients with agenesis of the corpus callosum, functional MR imaging was performed while patients performed text-listening and finger-tapping tasks. Functional images were also acquired while the patients performed no specific task (resting state). Regions of activation temporally correlated with the performance of the tasks were identified by cross-correlating the task data with a reference function. Voxel clusters (seed voxels) that corresponded to regions of activation in the task-activation data set were selected in...

The overall goal of this study was the development and application of a less motion sensitive, si... more The overall goal of this study was the development and application of a less motion sensitive, single-shot MRI technique for use on a standard clinical system in a dynamic imaging setting, such as cardiac scanning. Time encoding, a single-shot line scanning technique, has been used to produce single-shot, small field-of-view cardiac images without the use of presaturation pulses. The major advantages of this method are: (1) as a line scanning technique, time encoding is minimally sensitive to motion when compared with 2D Fourier methods, and (2) aliasing will not occur if the object being imaged extends beyond the field of view.

Technology in cancer research & treatment, 2010

Twenty-four patients with proven benign and low-grade brain neoplasms each performed two iteratio... more Twenty-four patients with proven benign and low-grade brain neoplasms each performed two iterations of four fMRI paradigms: language (word generation), primary and association auditory (text listening), upper limb fine motor control (alternating-limb bilateral finger tapping), and primary visual perception (reversing checkerboard). Activation clusters with varying thresholds were generated for each scan and used to calculate reproducibility parameters: Difference in the Center of Mass (COM) location, R(size), and R(overlap). The average difference in the COM, R(size), and R(overlap) values ranged from 1.70 +/- 0.53 mm -10.60 +/- 3.21 mm, 0.6 +/- 0.04-0.90 +/- 0.05 and 0.23 +/- 0.12 -1 +/- 0.16 respectively for all tasks. These values are within the range of, or higher than, previously published reports on fMRI test-retest precision. FMRI is indicated to be a noninvasive tool with acceptable reproducibility measures for assessing the localizations of multiple language and sensorimoto...

Ajnr American Journal of Neuroradiology, Sep 1, 2000

With functional connectivity functional MR imaging, covariance in signal intensity has been shown... more With functional connectivity functional MR imaging, covariance in signal intensity has been shown in functionally related regions of brain in participants instructed to perform no cognitive task. These changes are thought to represent synchronous fluctuations in blood flow, which imply neuronal connections between the regions. The purpose of this study was to map functional connectivity in subcortical nuclei with functional connectivity functional MR imaging.

American Journal of Neuroradiology, Jun 1, 2000

Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produc... more Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produce transient neuronal activity in subcortical regions. We tested the hypothesis that a reference function modeling a transient hemodynamic response would more reliably detect activation in the basal ganglia than would a conventional reference function, which models a sustained hemodynamic response.

Ajnr American Journal of Neuroradiology, Oct 1, 2000

In subjects who are performing no prescribed cognitive task, functional connectivity mapped with ... more In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks.

Neuroradiology, 2002

This study was designed to compare the test-retest precision of functional magnetic resonance ima... more This study was designed to compare the test-retest precision of functional magnetic resonance imaging (fMRI) data processed with independent component analysis (ICA) and the same data analyzed with a conventional model-dependent method (Student's- t mapping). Volunteers underwent two or three iterations of visual and auditory stimuli, while data were collected for fMRI scans. The scan data were separately processed with ICA and with Student's- t mapping (STM). As a measure of test-retest precision, concurrence ratios were calculated for each subject and each task as the number of voxels that were activated by two iterations of a task divided by the average number of voxels activated in each repetition. In 28 test-retest comparisons, the average concurrence ratio was 0.69+/-0.10 for ICA and 0.65+/-0.13 for the conventional method, a statistically insignificant difference. In fMR image data of block stimulus paradigms, ICA had similar test-retest precision to a conventional model-dependent method.

American Journal of Neuroradiology

BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing... more BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a priori assumptions about the hemodynamic response to the task. The purpose of this study was to analyze the temporal characteristics and the spatial mapping of the independent components identified by ICA when the subject performs a finger-tapping task.

American Journal of Neuroradiology

Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produc... more Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produce transient neuronal activity in subcortical regions. We tested the hypothesis that a reference function modeling a transient hemodynamic response would more reliably detect activation in the basal ganglia than would a conventional reference function, which models a sustained hemodynamic response.

American Journal of Neuroradiology

In subjects who are performing no prescribed cognitive task, functional connectivity mapped with ... more In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks.

BACKGROUND AND PURPOSE: Functional connectivity MR (fcMR) imaging is used to map regions of brain... more BACKGROUND AND PURPOSE: Functional connectivity MR (fcMR) imaging is used to map regions of brain with synchronous, regional, slow fluctuations in cerebral blood flow. We tested the hypothesis that focal cerebral lesions do not eradicate expected functional connectivity. METHODS: Functional MR (fMR) and fcMR maps were acquired for 12 patients with focal cerebral tumors, cysts, arteriovenous malformations, or in one

AJNR. American journal of neuroradiology, 2000

In subjects who are performing no prescribed cognitive task, functional connectivity mapped with ... more In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks. In four volunteers, task-activation fMRI and functional connectivity (resting-state) fcMRI data were acquired. A small region of interest (in an area that showed maximal task activation) was chosen, and the correlation coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated. The correlation coefficient was decomposed into frequency component...

AJNR. American journal of neuroradiology, 2000

Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) ima... more Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a priori assumptions about the hemodynamic response to the task. The purpose of this study was to analyze the temporal characteristics and the spatial mapping of the independent components identified by ICA when the subject performs a finger-tapping task. Ten healthy subjects performed variations of the finger-tapping task conventionally used to map the sensorimotor cortex. The scan data were processed with ICA, and the temporal configuration of the components and their spatial localizations were studied. The locations with activation were tabulated and compared with locations known to be involved in the organization of motor functions in the brain. Components were identified that correlated to varying degrees with the conventional boxcar reference function. One or more of these components mapped to the sensorimotor cortex, supplementary motor area (SMA), putamen, ...

AJNR. American journal of neuroradiology, 2000

With functional connectivity functional MR imaging, co-variance in signal intensity has been show... more With functional connectivity functional MR imaging, co-variance in signal intensity has been shown in functionally related regions of brain in participants instructed to perform no cognitive task. These changes are thought to represent synchronous fluctuations in blood flow, which imply neuronal connections between the regions. The purpose of this study was to map functional connectivity in subcortical nuclei with functional connectivity functional MR imaging. Imaging data were acquired with an echo-planar sequence from six volunteers who performed no specific cognitive task. For functional connectivity functional MR imaging, a "seed" voxel or group of voxels was selected from the resting data set in the thalamus or in the hippocampus. Control voxels in gray matter presumed not to be eloquent cortex were also chosen. The correlation coefficient of the seed voxels and the control voxels with every other voxel in the resting data set was calculated. The voxels with correlati...

American Journal of Neuroradiology, 2003

Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the ... more Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the hemispheres. This synchrony implies neuronal connections between brain regions. The synchrony of blood flow changes is defined operationally as functional connectivity. Our purpose was to measure functional connectivity in patients with corpus callosal agenesis, in whom the interhemispheric connectivity is hypothetically diminished. In three patients with agenesis of the corpus callosum, functional MR imaging was performed while patients performed text-listening and finger-tapping tasks. Functional images were also acquired while the patients performed no specific task (resting state). Regions of activation temporally correlated with the performance of the tasks were identified by cross-correlating the task data with a reference function. Voxel clusters (seed voxels) that corresponded to regions of activation in the task-activation data set were selected in the resting data set. All the ...

Human Brain Mapping, 2003

Independent component analysis (ICA) has been demonstrated to be an effective data-driven method ... more Independent component analysis (ICA) has been demonstrated to be an effective data-driven method for analyzing fMRI data. However, a method for objective differentiation of task-related components from those that are artifactually non-relevant is needed. We propose a method of constant-cycle (periodic) fMRI task paradigm combined with ranking of spatial ICA components by the magnitude contribution of their temporal aspects to the fundamental task frequency. Power spectrum ranking shares some similarity to correlation with an a priori hemodynamic response, but without a need to presume an exact timing or duration of the fMRI response. When applied to a complex motor task paradigm with auditory cues, multiple task-related activations are successfully identified and separated from artifactual components. These activations include sensorimotor, auditory, and superior parietal areas. Comparisons of task-related component time courses indicate the temporal relationship of fMRI responses in functionally involved regions. Results indicate the sensitivity of ICA to short-duration hemodynamics, and the efficacy of a power spectrum ranking method for identification of task-related components.

Neurosurgical Focus, 2013

Object Functional MRI (fMRI) has proven to be an effective component of pretreatment planning in ... more Object Functional MRI (fMRI) has proven to be an effective component of pretreatment planning in patients harboring a variety of different brain lesions. The authors have recently reported significant relationships concerning distances between brain tumor borders and areas of functional activation (lesion-to-activation distance; LAD) with regard to patient morbidity and mortality. This study further examines the relationship between LAD, focusing on a host of vascular lesions and pre- and posttreatment morbidity. Methods This study included a sample population of patients with vascular lesions (n = 106), primarily arteriovenous malformations (AVMs) and cavernomas. These patients underwent pretreatment fMRI-based motor mapping (n = 72) or language mapping (n = 84). The impact of LAD and other variables derived from the patient medical record were analyzed with respect to functional deficits in terms of morbidity (weakness and/or aphasia). Results In patients with no pretreatment defi...

Background and Purpose—Functional magnetic resonance imaging (fMRI) has proven to be an effective... more Background and Purpose—Functional magnetic resonance imaging (fMRI) has proven to be an effective component of pretreatment planning in patients harboring a variety of different brain lesions. Our group has recently reported significant relationships concerning distances between brain tumor border and area of functional activation (Lesion-to-Activation-Distance; LAD) with regard to patient morbidity and mortality. This study further examines the relationship between LAD, focusing on a host of vascular lesions, and preand posttreatment morbidity. Materials and Methods—This study included a sample population (n=106) of patients with vascular lesions, primarily arteriovenous malformations (AVM) and cavernomas. These patients underwent pretreatment fMRI-based motor mapping (n=72) or language mapping (n=84). The impact of LAD and other variables derived from the patient medical record were analyzed with respect to functional deficits in terms of morbidity (weakness and/or aphasia). Resul...

BACKGROUND AND PURPOSE Regional cerebral blood flow fluctuates synchronously in corresponding bra... more BACKGROUND AND PURPOSE Regional cerebral blood flow fluctuates synchronously in corresponding brain regions between the hemispheres. This synchrony implies neuronal connections between brain regions. The synchrony of blood flow changes is defined operationally as functional connectivity. Our purpose was to measure functional connectivity in patients with corpus callosal agenesis, in whom the interhemispheric connectivity is hypothetically diminished. METHODS In three patients with agenesis of the corpus callosum, functional MR imaging was performed while patients performed text-listening and finger-tapping tasks. Functional images were also acquired while the patients performed no specific task (resting state). Regions of activation temporally correlated with the performance of the tasks were identified by cross-correlating the task data with a reference function. Voxel clusters (seed voxels) that corresponded to regions of activation in the task-activation data set were selected in...

The overall goal of this study was the development and application of a less motion sensitive, si... more The overall goal of this study was the development and application of a less motion sensitive, single-shot MRI technique for use on a standard clinical system in a dynamic imaging setting, such as cardiac scanning. Time encoding, a single-shot line scanning technique, has been used to produce single-shot, small field-of-view cardiac images without the use of presaturation pulses. The major advantages of this method are: (1) as a line scanning technique, time encoding is minimally sensitive to motion when compared with 2D Fourier methods, and (2) aliasing will not occur if the object being imaged extends beyond the field of view.

Technology in cancer research & treatment, 2010

Twenty-four patients with proven benign and low-grade brain neoplasms each performed two iteratio... more Twenty-four patients with proven benign and low-grade brain neoplasms each performed two iterations of four fMRI paradigms: language (word generation), primary and association auditory (text listening), upper limb fine motor control (alternating-limb bilateral finger tapping), and primary visual perception (reversing checkerboard). Activation clusters with varying thresholds were generated for each scan and used to calculate reproducibility parameters: Difference in the Center of Mass (COM) location, R(size), and R(overlap). The average difference in the COM, R(size), and R(overlap) values ranged from 1.70 +/- 0.53 mm -10.60 +/- 3.21 mm, 0.6 +/- 0.04-0.90 +/- 0.05 and 0.23 +/- 0.12 -1 +/- 0.16 respectively for all tasks. These values are within the range of, or higher than, previously published reports on fMRI test-retest precision. FMRI is indicated to be a noninvasive tool with acceptable reproducibility measures for assessing the localizations of multiple language and sensorimoto...

Ajnr American Journal of Neuroradiology, Sep 1, 2000

With functional connectivity functional MR imaging, covariance in signal intensity has been shown... more With functional connectivity functional MR imaging, covariance in signal intensity has been shown in functionally related regions of brain in participants instructed to perform no cognitive task. These changes are thought to represent synchronous fluctuations in blood flow, which imply neuronal connections between the regions. The purpose of this study was to map functional connectivity in subcortical nuclei with functional connectivity functional MR imaging.

American Journal of Neuroradiology, Jun 1, 2000

Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produc... more Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produce transient neuronal activity in subcortical regions. We tested the hypothesis that a reference function modeling a transient hemodynamic response would more reliably detect activation in the basal ganglia than would a conventional reference function, which models a sustained hemodynamic response.

Ajnr American Journal of Neuroradiology, Oct 1, 2000

In subjects who are performing no prescribed cognitive task, functional connectivity mapped with ... more In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks.

Neuroradiology, 2002

This study was designed to compare the test-retest precision of functional magnetic resonance ima... more This study was designed to compare the test-retest precision of functional magnetic resonance imaging (fMRI) data processed with independent component analysis (ICA) and the same data analyzed with a conventional model-dependent method (Student's- t mapping). Volunteers underwent two or three iterations of visual and auditory stimuli, while data were collected for fMRI scans. The scan data were separately processed with ICA and with Student's- t mapping (STM). As a measure of test-retest precision, concurrence ratios were calculated for each subject and each task as the number of voxels that were activated by two iterations of a task divided by the average number of voxels activated in each repetition. In 28 test-retest comparisons, the average concurrence ratio was 0.69+/-0.10 for ICA and 0.65+/-0.13 for the conventional method, a statistically insignificant difference. In fMR image data of block stimulus paradigms, ICA had similar test-retest precision to a conventional model-dependent method.

American Journal of Neuroradiology

BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing... more BACKGROUND AND PURPOSE: Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a priori assumptions about the hemodynamic response to the task. The purpose of this study was to analyze the temporal characteristics and the spatial mapping of the independent components identified by ICA when the subject performs a finger-tapping task.

American Journal of Neuroradiology

Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produc... more Repetitive motor tasks that produce sustained neuronal activity in the sensorimotor cortex produce transient neuronal activity in subcortical regions. We tested the hypothesis that a reference function modeling a transient hemodynamic response would more reliably detect activation in the basal ganglia than would a conventional reference function, which models a sustained hemodynamic response.

American Journal of Neuroradiology

In subjects who are performing no prescribed cognitive task, functional connectivity mapped with ... more In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks.

BACKGROUND AND PURPOSE: Functional connectivity MR (fcMR) imaging is used to map regions of brain... more BACKGROUND AND PURPOSE: Functional connectivity MR (fcMR) imaging is used to map regions of brain with synchronous, regional, slow fluctuations in cerebral blood flow. We tested the hypothesis that focal cerebral lesions do not eradicate expected functional connectivity. METHODS: Functional MR (fMR) and fcMR maps were acquired for 12 patients with focal cerebral tumors, cysts, arteriovenous malformations, or in one

AJNR. American journal of neuroradiology, 2000

In subjects who are performing no prescribed cognitive task, functional connectivity mapped with ... more In subjects who are performing no prescribed cognitive task, functional connectivity mapped with MR imaging (fcMRI) shows regions with synchronous fluctuations of cerebral blood flow. When specific tasks are performed, functional MR imaging (fMRI) can map locations in which regional cerebral blood flow increases synchronously with the performance of the task. We tested the hypothesis that fcMRI maps, based on the synchrony of low-frequency blood flow fluctuations, identify brain regions that show activation on fMRI maps of sensorimotor, visual, language, and auditory tasks. In four volunteers, task-activation fMRI and functional connectivity (resting-state) fcMRI data were acquired. A small region of interest (in an area that showed maximal task activation) was chosen, and the correlation coefficient of the corresponding resting-state signal with the signal of all other voxels in the resting data set was calculated. The correlation coefficient was decomposed into frequency component...

AJNR. American journal of neuroradiology, 2000

Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) ima... more Independent component analysis (ICA), unlike other methods for processing functional MR (fMR) imaging data, requires no a priori assumptions about the hemodynamic response to the task. The purpose of this study was to analyze the temporal characteristics and the spatial mapping of the independent components identified by ICA when the subject performs a finger-tapping task. Ten healthy subjects performed variations of the finger-tapping task conventionally used to map the sensorimotor cortex. The scan data were processed with ICA, and the temporal configuration of the components and their spatial localizations were studied. The locations with activation were tabulated and compared with locations known to be involved in the organization of motor functions in the brain. Components were identified that correlated to varying degrees with the conventional boxcar reference function. One or more of these components mapped to the sensorimotor cortex, supplementary motor area (SMA), putamen, ...

AJNR. American journal of neuroradiology, 2000

With functional connectivity functional MR imaging, co-variance in signal intensity has been show... more With functional connectivity functional MR imaging, co-variance in signal intensity has been shown in functionally related regions of brain in participants instructed to perform no cognitive task. These changes are thought to represent synchronous fluctuations in blood flow, which imply neuronal connections between the regions. The purpose of this study was to map functional connectivity in subcortical nuclei with functional connectivity functional MR imaging. Imaging data were acquired with an echo-planar sequence from six volunteers who performed no specific cognitive task. For functional connectivity functional MR imaging, a "seed" voxel or group of voxels was selected from the resting data set in the thalamus or in the hippocampus. Control voxels in gray matter presumed not to be eloquent cortex were also chosen. The correlation coefficient of the seed voxels and the control voxels with every other voxel in the resting data set was calculated. The voxels with correlati...