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Cortical network for gaze control in humans revealed using multimodal MRI.

Anderson EJ, Jones DK, O'Gorman RL, Leemans A, Catani M, Husain M - Cereb. Cortex (2011)

Bottom Line: The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys.In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans.These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans.

View Article: PubMed Central - PubMed

Affiliation: UCL Institute of Cognitive Neuroscience, London WC1N 3AR, UK. e.anderson@fil.ion.ucl.ac.uk

ABSTRACT
Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans.

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Anatomical definition of the ROIs. For stage 1 of the analysis, all ROIs were defined on the individual FA maps, using anatomical landmarks for guidance and were drawn to encompass white matter underlying regions of cortex known to include the FEF, SEF, and PEF. Selected axial slices of the FA map for a representative subject are illustrated above, with voxels to be included in the right FEF, SEF, and PEF ROIs outlined in orange. Note that the frontal and parietal ROIs do not cross the central sulcus (red line) and the FEF and SEF ROIs do not cross the internal capsule. For clarity, not all slices are illustrated in this figure—for full details of the X, Y, and Z ranges included in each ROI, see Materials and Methods. The Z coordinates given are approximate, as the individual FA maps were not normalized to the MNI template for the individual subject analyses.
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fig2: Anatomical definition of the ROIs. For stage 1 of the analysis, all ROIs were defined on the individual FA maps, using anatomical landmarks for guidance and were drawn to encompass white matter underlying regions of cortex known to include the FEF, SEF, and PEF. Selected axial slices of the FA map for a representative subject are illustrated above, with voxels to be included in the right FEF, SEF, and PEF ROIs outlined in orange. Note that the frontal and parietal ROIs do not cross the central sulcus (red line) and the FEF and SEF ROIs do not cross the internal capsule. For clarity, not all slices are illustrated in this figure—for full details of the X, Y, and Z ranges included in each ROI, see Materials and Methods. The Z coordinates given are approximate, as the individual FA maps were not normalized to the MNI template for the individual subject analyses.

Mentions: For stage 1 of the analysis, all ROIs were defined on axial slices of the FA map, which clearly highlights the boundary between white and gray matter (Fig. 2). Initially, for all subjects, 2 large ROIs were defined in the superior frontal lobe (SEF ROI) and middle frontal lobe (FEF ROI) of each hemisphere, using anatomical landmarks for guidance. ROIs were defined to encompass a large region of white matter lying directly beneath regions of cortex known to include the human SEF and FEF. For the FEF ROI, a region of white matter underlying the middle and superior frontal gyrus, lateral to the internal capsule, and anterior to the central sulcus, was defined (approximate Brodmann areas [BAs] 44, 8, 6, and 4). The approximate MNI coordinates for this region ranged in the X direction from 25 to 60, in the Y direction from −10 to 25, and from 20 to 60 in the Z direction. These coordinates varied depending on individual anatomy. For the SEF region, a region of superior frontal cortex medial to the internal capsule and anterior to the central sulcus, underlying the precentral gyrus (BAs 4 and 6), was defined (approximate X range: 4–20, Y range: −15 to 10, Z range: 45–70).


Cortical network for gaze control in humans revealed using multimodal MRI.

Anderson EJ, Jones DK, O'Gorman RL, Leemans A, Catani M, Husain M - Cereb. Cortex (2011)

Anatomical definition of the ROIs. For stage 1 of the analysis, all ROIs were defined on the individual FA maps, using anatomical landmarks for guidance and were drawn to encompass white matter underlying regions of cortex known to include the FEF, SEF, and PEF. Selected axial slices of the FA map for a representative subject are illustrated above, with voxels to be included in the right FEF, SEF, and PEF ROIs outlined in orange. Note that the frontal and parietal ROIs do not cross the central sulcus (red line) and the FEF and SEF ROIs do not cross the internal capsule. For clarity, not all slices are illustrated in this figure—for full details of the X, Y, and Z ranges included in each ROI, see Materials and Methods. The Z coordinates given are approximate, as the individual FA maps were not normalized to the MNI template for the individual subject analyses.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3306571&req=5

fig2: Anatomical definition of the ROIs. For stage 1 of the analysis, all ROIs were defined on the individual FA maps, using anatomical landmarks for guidance and were drawn to encompass white matter underlying regions of cortex known to include the FEF, SEF, and PEF. Selected axial slices of the FA map for a representative subject are illustrated above, with voxels to be included in the right FEF, SEF, and PEF ROIs outlined in orange. Note that the frontal and parietal ROIs do not cross the central sulcus (red line) and the FEF and SEF ROIs do not cross the internal capsule. For clarity, not all slices are illustrated in this figure—for full details of the X, Y, and Z ranges included in each ROI, see Materials and Methods. The Z coordinates given are approximate, as the individual FA maps were not normalized to the MNI template for the individual subject analyses.
Mentions: For stage 1 of the analysis, all ROIs were defined on axial slices of the FA map, which clearly highlights the boundary between white and gray matter (Fig. 2). Initially, for all subjects, 2 large ROIs were defined in the superior frontal lobe (SEF ROI) and middle frontal lobe (FEF ROI) of each hemisphere, using anatomical landmarks for guidance. ROIs were defined to encompass a large region of white matter lying directly beneath regions of cortex known to include the human SEF and FEF. For the FEF ROI, a region of white matter underlying the middle and superior frontal gyrus, lateral to the internal capsule, and anterior to the central sulcus, was defined (approximate Brodmann areas [BAs] 44, 8, 6, and 4). The approximate MNI coordinates for this region ranged in the X direction from 25 to 60, in the Y direction from −10 to 25, and from 20 to 60 in the Z direction. These coordinates varied depending on individual anatomy. For the SEF region, a region of superior frontal cortex medial to the internal capsule and anterior to the central sulcus, underlying the precentral gyrus (BAs 4 and 6), was defined (approximate X range: 4–20, Y range: −15 to 10, Z range: 45–70).

Bottom Line: The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys.In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans.These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans.

View Article: PubMed Central - PubMed

Affiliation: UCL Institute of Cognitive Neuroscience, London WC1N 3AR, UK. e.anderson@fil.ion.ucl.ac.uk

ABSTRACT
Functional magnetic resonance imaging (fMRI) techniques allow definition of cortical nodes that are presumed to be components of large-scale distributed brain networks involved in cognitive processes. However, very few investigations examine whether such functionally defined areas are in fact structurally connected. Here, we used combined fMRI and diffusion MRI-based tractography to define the cortical network involved in saccadic eye movement control in humans. The results of this multimodal imaging approach demonstrate white matter pathways connecting the frontal eye fields and supplementary eye fields, consistent with the known connectivity of these regions in macaque monkeys. Importantly, however, these connections appeared to be more prominent in the right hemisphere of humans. In addition, there was evidence of a dorsal frontoparietal pathway connecting the frontal eye field and the inferior parietal lobe, also right hemisphere dominant, consistent with specialization of the right hemisphere for directed attention in humans. These findings demonstrate the utility and potential of using multimodal imaging techniques to define large-scale distributed brain networks, including those that demonstrate known hemispheric asymmetries in humans.

Show MeSH