TY - JOUR
T1 - Advances in high-resolution imaging and computational unfolding of the human hippocampus
AU - Ekstrom, Arne D.
AU - Bazih, Adam J.
AU - Suthana, Nanthia A.
AU - Al-Hakim, Ramsey
AU - Ogura, Kenji
AU - Zeineh, Michael
AU - Burggren, Alison C.
AU - Bookheimer, Susan Y.
N1 - Funding Information:
We thank Paul Thompson and Mark Cohen for contributing the computer code and technical guidance on the results in this manuscript. We thank John Melanokas for generous sharing of computer code central to the interpolation software. We thank Saba Movishari for technical assistance. We also thank NINDS F32 NS50067 for financial support to AE. For generous support the authors thank the Brain Mapping Medical Research Organization, Brain Mapping Support Foundation, Pierson-Lovelace Foundation, The Ahmanson Foundation, William M. and Linda R. Dietel Philanthropic Fund at the Northern Piedmont Community Foundation, Tamkin Foundation, Jennifer Jones-Simon Foundation, Capital Group Companies Charitable Foundation, Robson Family and Northstar Fund.
PY - 2009/8/1
Y1 - 2009/8/1
N2 - The hippocampus is often a difficult structure to visualize with magnetic resonance imaging (MRI) and functional MRI (fMRI) due to its convoluted nature and susceptibility to signal dropout. Improving our ability to pinpoint changes in neural activity using fMRI in this structure remains an important challenge. Current fMRI/MRI methods typically do not permit visualization of the hippocampus and surrounding cortex at a resolution less than 1 mm. We present here improvements to our previous methods for obtaining structural MR images of the hippocampus, which provided an in-plane resolution of 0.4 mm2 mm and two-dimensional "flat" maps of the hippocampus with an interpolated isotropic resolution of 0.4 mm3 (Engel, S.A., Glover, G.H., and Wandell, B.A., (1997). Retinotopic organization in human visual cortex and the spatial precision of functional MRI. Cereb. Cortex 7, 181-192.; Zeineh, M.M., Engel, S.A., and Bookheimer, S.Y., (2000). Application of cortical unfolding techniques to functional MRI of the human hippocampal region. NeuroImage 11, 668-683.). We present changes to existing structural imaging sequences that now augment the resolution of previous scans, permitting visualization of the anterior portion of CA1, parts of the dentate gyrus, and CA23. These imaging improvements are of relevance generally to the field of imaging because they permit higher overall resolution imaging of the hippocampus than previously possible (at 3 T). We also introduce a novel application of a computational interpolation method that improves our ability to capture the convoluted three-dimensional shape of the hippocampus. Furthermore, we have developed a quantitative method for obtaining group activation patterns based on producing averaged flat maps using vector field warping techniques, allowing localization of activations to specific hippocampal subregions across groups of subjects. Together, these methods provide a means to improve imaging of neural activity in the human hippocampus and surrounding cortex during cognitive tasks.
AB - The hippocampus is often a difficult structure to visualize with magnetic resonance imaging (MRI) and functional MRI (fMRI) due to its convoluted nature and susceptibility to signal dropout. Improving our ability to pinpoint changes in neural activity using fMRI in this structure remains an important challenge. Current fMRI/MRI methods typically do not permit visualization of the hippocampus and surrounding cortex at a resolution less than 1 mm. We present here improvements to our previous methods for obtaining structural MR images of the hippocampus, which provided an in-plane resolution of 0.4 mm2 mm and two-dimensional "flat" maps of the hippocampus with an interpolated isotropic resolution of 0.4 mm3 (Engel, S.A., Glover, G.H., and Wandell, B.A., (1997). Retinotopic organization in human visual cortex and the spatial precision of functional MRI. Cereb. Cortex 7, 181-192.; Zeineh, M.M., Engel, S.A., and Bookheimer, S.Y., (2000). Application of cortical unfolding techniques to functional MRI of the human hippocampal region. NeuroImage 11, 668-683.). We present changes to existing structural imaging sequences that now augment the resolution of previous scans, permitting visualization of the anterior portion of CA1, parts of the dentate gyrus, and CA23. These imaging improvements are of relevance generally to the field of imaging because they permit higher overall resolution imaging of the hippocampus than previously possible (at 3 T). We also introduce a novel application of a computational interpolation method that improves our ability to capture the convoluted three-dimensional shape of the hippocampus. Furthermore, we have developed a quantitative method for obtaining group activation patterns based on producing averaged flat maps using vector field warping techniques, allowing localization of activations to specific hippocampal subregions across groups of subjects. Together, these methods provide a means to improve imaging of neural activity in the human hippocampus and surrounding cortex during cognitive tasks.
KW - High-resolution imaging
KW - Hippocampus
KW - MRI
KW - fMRI
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U2 - 10.1016/j.neuroimage.2009.03.017
DO - 10.1016/j.neuroimage.2009.03.017
M3 - Article
C2 - 19303448
AN - SCOPUS:67349253427
SN - 1053-8119
VL - 47
SP - 42
EP - 49
JO - NeuroImage
JF - NeuroImage
IS - 1
ER -