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Preserved Functional Specialization for Spatial processing in the Middle Occipital Gyrus of the Early Blind

NEURON 2010年第1期68卷 138-148页

作者： Renier, Laurent A. Anurova, Irina De Volder, Anne G. Carlson, Synnove VanMeter, John Rauschecker, Josef P. Georgetown Univ Med Ctr Dept Physiol & Biophys Lab Integrat Neurosci & Cognit Washington DC 20007 USA Catholic Univ Louvain Inst Neurosci B-1200 Brussels Belgium Univ Helsinki Inst Biomed Physiol Neurosci Unit FIN-00014 Helsinki Finland Aalto Univ Sch Sci & Technol Low Temp Lab Brain Res Unit FI-00076 Aalto Finland Univ Tampere Sch Med Tampere 33014 Finland Georgetown Univ Med Ctr Ctr Funct & Mol Imaging Washington DC 20007 USA Aalto Univ Sch Sci & Technol Ctr Excellence Computat Complex Syst Res Mind & Brain Lab FI-00076 Aalto Finland

The occipital cortex (OC) of early-blind humans is activated during various nonvisual perceptual and cognitive tasks, but little is known about its modular organization. Using functional MRI we tested whether processing of auditory versus tactile and spatial versus nonspatial information was dissociated in the OC of the early blind. No modality-specific OC activation was observed. However, the right middle occipital gyrus (MOG) showed a preference for spatial over nonspatial processing of both auditory and tactile stimuli. Furthermore, MOG activity was correlated with accuracy of individual sound localization performance. In sighted controls, most of extrastriate OC, including the MOG, was deactivated during auditory and tactile conditions, but the right MOG was more activated during spatial than nonspatial visual tasks. Thus, although the sensory modalities driving the neurons in the reorganized OC of blind individuals are altered, the functional specialization of extrastriate cortex is retained regardless of visual experience.

关键词： Acoustic Stimulation/methods Adult Analysis of Variance Blindness/pathology Blindness/physiopathology Brain Mapping Brain Mapping Case-Control Studies Female Humans image processing, computer-assisted/methods Magnetic Resonance Imaging/methods Male Middle Aged Occipital Lobe/blood supply Occipital Lobe/physiopathology Oxygen/blood Sound Localization/physiology Space Perception/physiology Touch/physiology

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Joint analysis of structural and perfusion MRI for cognitive assessment and classification of Alzheimer's disease and normal aging

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NEUROimage 2010年第1期52卷 186-197页

作者： Tosun, Duygu Mojabi, Pouria Weiner, Michael W. Schuff, Norbert Dept Vet Afrairs Med Ctr Ctr Imaging Neurodegenerat Dis San Francisco CA 94121 USA Univ Calif San Francisco Dept Radiol San Francisco CA 94143 USA

Structural magnetic resonance imaging (MRI) of brain tissue loss and physiological imaging of regional cerebral blood flow (rCBF) can provide complimentary information for the characterization of brain disorders, such as Alzheimer's disease (AD) but studies into gains in classification power for AD using these image modalities Jointly have been limited Our aim in this study was to determine the Joint contribution of structural and perfusion-weighted imaging for the classification of AD in a cross-sectional study using an integrated multimodality MRI processing framework and a cortical surface-based analysis approach We used logistic regression analysis to determine sequentially the value of cortical thickness, rCBF, and cortical thickness and rCBF Jointly for classification for diagnosis of AD compared to controls We further tested the extent to which cortical thinning and reduced rCBF explain individually or together variability in dementia severity Separate analysis of structural MRI and perfusion-weighted MRI data yielded the well-established pattern of cortical thinning and rCBF reduction in AD, affecting predominantly temporo-parietal brain regions Using structural MRI and perfusion-weighted MRI Jointly indicated that cortical thinning dominated the classification of AD and controls without significant contributions from rCBF However there was also a positive interaction between reduced rCBF and cortical thinning in the right superior temporal sulcus, implying that structural and physiological brain alterations in AD can be complementary Compared to reduced rCBF, regional cortical thinning better explained the variability in dementia severity In conclusion, structural brain alterations compared to physiological variations are the dominant features of MRI in AD (C) 2010 Elsevier Inc All rights reserved.

关键词： Aged Aged, 80 and over Aging/pathology Aging/physiology Alzheimer Disease/pathology Alzheimer Disease/physiopathology Brain/blood supply Brain/pathology Brain/physiopathology Cerebral Cortex/parasitology Cerebral Cortex/pathology Cerebral Cortex/physiopathology Cerebrovascular Circulation Cognition/physiology Cross-Sectional Studies Female Humans image processing, computer-assisted/methods Logistic Models Magnetic Resonance Angiography/methods Magnetic Resonance Imaging/methods Male Middle Aged Organ Size Regional Blood Flow Severity of Illness Index Severity of Illness Index Signal processing, computer-assisted

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COMPARISONS OF methods TO DETECT GLAUCOMATOUS OPTIC-NERVE DAMAGE

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OPHTHALMOLOGY 1993年第10期100卷 1498-1503页

作者： OCONNOR, DJ ZEYEN, T CAPRIOLI, J YALE UNIV SCH MEDDEPT OPHTHALMOL & VISUAL SCIGLAUCOMA SECT330 CEDAR STNEW HAVENCT 06510

Purpose. Various techniques of optic disc and nerve fiber layer evaluation may be used to detect structural glaucomatous damage. The authors compared several qualitative and quantitative methods to determine their relative sensitivities and specificities to detect the presence of glaucomatous visual field loss. methods: Fifty-one healthy eyes, 169 ocular hypertensive eyes with normal visual fields, and 132 glaucomatous eyes with early visual field defects were evaluated with qualitative and quantitative measures of structural damage to the optic nerve and nerve fiber layer. Qualitative evaluations were performed by three experienced masked observers who independently graded stereoscopic color disc and monochromatic nerve fiber layer photographs. Quantitative measurements of disc rim area and nerve fiber layer height were made with digitized image analysis of videographic images. Manual planimetric measurements of disc rim area were made from enlarged prints of stereoscopic optic disc photographs. Diagnostic precision was defined as the total proportion of correct diagnoses for the presence or absence of visual field loss. Results: The diagnostic precision of results of a quantitative disc examination (81%) was greater than those of a qualitative nerve fiber layer examination (75%). Quantitative nerve fiber height measurement had the highest sensitivity rate (73%) and results of the qualitative disc examination had the highest specificity rate (87%) of the methods tested. Conclusion: The diagnostic precision of disc evaluation was superior to other methods, including nerve fiber layer examination, in correctly determining the presence of structural glaucomatous damage at the earl visual field loss stage.

关键词： Adult Female Glaucoma/complications Humans image processing, computer-assisted/methods Male Middle Aged Nerve Fibers/pathology Ocular Hypertension/complications Optic Nerve/pathology Optic Nerve Diseases/diagnosis Optic Nerve Diseases/etiology Perimetry/methods Photography/methods Reproducibility of Results Sensitivity and Specificity Vision Disorders/diagnosis Visual Fields

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Analyzing protein-protein interactions in cell membranes

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BIOESSAYS 2004年第2期26卷 196-203页

作者： Nohe, A Petersen, NO Univ Western Ontario Dept Chem London ON N6A 5B7 Canada

Interactions among membrane proteins regulate numerous cellular processes, including cell growth, cell differentiation and apoptosis. We need to understand which proteins interact, where they interact and to which extent they interact. This article describes a set of novel approaches to measure, on the surface of living cells, the number of clusters of proteins, the number of proteins per cluster, the number of clusters or membrane domains that contain pairs of interacting proteins and the fraction of one protein species that interacts with another protein within these domains. These data can then be interpreted in terms of the function of the protein-protein interactions. (C) 2004 Wiley Periodicals, Inc.

关键词： Cell Membrane/chemistry Cell Membrane/metabolism Cells, Cultured Glycosylphosphatidylinositols Humans image processing, computer-assisted/methods Membrane Proteins/metabolism Protein Interaction Mapping/methods Statistics as Topic

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Comparison of human septal nuclei MRI measurements using automated segmentation and a new manual protocol based on histology

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NEUROimage 2014年 97卷 245-251页

作者： Butler, Tracy Zaborszky, Laszlo Pirraglia, Elizabeth Li, Jinyu Wang, Xiuyuan Hugh Li, Yi Tsui, Wai Talos, Delia Devinsky, Orrin Kuchna, Izabela Nowicki, Krzysztof French, Jacqueline Kuzniecky, Rubin Wegiel, Jerzy Glodzik, Lidia Rusinek, Henry deLeon, Mony J. Thesen, Thomas NYU Sch Med Ctr Brain Hlth Dept Psychiat New York NY 10016 USA NYU Sch Med Comprehens Epilepsy Ctr Dept Neurol New York NY 10016 USA Rutgers State Univ Ctr Mol & Behav Neurosci Newark NJ 07102 USA New York State Inst Basic Res Dev Disabil Staten Isl NY 10314 USA

Septal nuclei, located in basal forebrain, are strongly connected with hippocampi and important in learning and memory, but have received limited research attention in human MRI studies. While probabilistic maps for estimating septal volume on MRI are now available, they have not been independently validated against manual tracing of MRI typically considered the gold standard for delineating brain structures. We developed a protocol for manual tracing of the human septal region on MRI based on examination of neuroanatomical specimens. We applied this tracing protocol to T1 MRI scans (n = 86) from subjects with temporal epilepsy and healthy controls to measure septal volume. To assess the inter-rater reliability of the protocol, a second tracer used the same protocol on 20 scans that were randomly selected from the 72 healthy controls. In addition to measuring septal volume, maximum septal thickness between the ventricles was measured and recorded. The same scans (n = 86) were also analyzed using septal probabilistic maps and DARTEL toolbox in SPM. Results show that our manual tracing algorithm is reliable, and that septal volume measurements obtained via manual and automated methods correlate significantly with each other (p<.001). Both manual and automated methods detected significantly enlarged septal nuclei in patients with temporal lobe epilepsy in accord with a proposed compensatory neuroplastic process related to the strong connections between septal nuclei and hippocampi. Septal thickness, which was simple to measure with excellent inter-rater reliability, correlated well with both manual and automated septal volume, suggesting it could serve as an easy-to-measure surrogate for septal volume in future studies. Our results call attention to the important though understudied human septal region, confirm its enlargement in temporal lobe epilepsy, and provide a reliable new manual delineation protocol that will facilitate continued study of this critical region.

关键词： Adolescent Adult Automation Brain Mapping Brain Mapping Epilepsy, Temporal Lobe/pathology Female Humans image processing, computer-assisted/methods Magnetic Resonance Imaging/methods Male Middle Aged Observer Variation Septal Nuclei/anatomy & histology Septal Nuclei/pathology Young Adult

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An analysis of image texture, tumor location, and MGMT promoter methylation in glioblastoma using magnetic resonance imaging

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NEUROimage 2010年第2期49卷 1398-1405页

作者： Drabycz, Sylvia Roldan, Gloria de Robles, Paula Adler, Daniel McIntyre, John B. Magliocco, Anthony M. Cairncross, J. Gregory Mitchell, J. Ross Univ Calgary Dept Elect & Comp Engn Calgary AB T2N 1N4 Canada Hotchkiss Brain Inst Calgary AB Canada Univ Calgary Dept Clin Neurosci Calgary AB T2N 1N4 Canada Univ Calgary Dept Pathol & Lab Med Calgary AB T2N 1N4 Canada Univ Calgary Dept Radiol Calgary AB T2N 1N4 Canada

In glioblastoma (GBM), promoter methylation of the DNA repair gene O-6-methylguanine-DNA methyltransferase (MGMT) is associated with benefit from chemotherapy. Correlations between MGMT promoter methylation and visually assessed imaging features on magnetic resonance (MR) have been reported suggesting that noninvasive detection of MGMT methylation status might be possible. Our study assessed whether MGMT methylation status in GBM could be predicted using MR imaging. We conducted a retrospective analysis of MR images in patients with newly diagnosed GBM. Tumor texture was assessed by two methods. First, we analyzed texture by expert consensus describing the tumor borders, presence or absence of cysts, pattern of enhancement, and appearance of tumor signal in T2-weighted images. Then, we applied space-frequency texture analysis based on the S-transform. Tumor location within the brain was determined using automatized image registration and segmentation techniques. Their association with MGMT methylation was analyzed. We confirmed that ring enhancement assessed visually is significantly associated with unmethylated MGMT promoter status (P = 0.006). Texture features on T2-weighted images assessed by the space-frequency analysis were significantly different between methylated and unmethylated cases (P<0.05). However, blinded classification of MGMT promoter methylation status reached an accuracy of only 71%. There were no significant differences in the locations of methylated and unmethylated GBM tumors. Our results provide further evidence that individual MR features are associated with MGMT methylation but better algorithms for predicting methylation status are needed. The relevance of this study lies on the application of novel techniques for the analysis of anatomical MR images of patients with GBM allowing the evaluation of subtleties not seen by an observer and facilitating the standardization of the methods, decreasing the potential for interobserver bias. (C) 2009

关键词： Adult Aged Aged, 80 and over Brain/metabolism Brain/pathology Brain Neoplasms/metabolism Brain Neoplasms/pathology DNA Methylation DNA Modification Methylases/genetics DNA Modification Methylases/metabolism DNA Repair Enzymes/genetics DNA Repair Enzymes/metabolism Female Glioblastoma/metabolism Glioblastoma/pathology Humans image processing, computer-assisted/methods Magnetic Resonance Imaging/methods Male Middle Aged Promoter Regions, Genetic Retrospective Studies Retrospective Studies Tumor Suppressor Proteins/genetics Tumor Suppressor Proteins/metabolism

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Modeling and analysis of mechanisms underlying fMRI-based decoding of information conveyed in cortical columns

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NEUROimage 2011年第2期56卷 627-642页

作者： Chaimow, Denis Yacoub, Essa Ugurbil, Kamil Shmuel, Amir McGill Univ Montreal Neurol Inst Dept Neurol & Neurosurg Montreal PQ H3A 2B4 Canada McGill Univ Montreal Neurol Inst Dept Biomed Engn Montreal PQ H3A 2B4 Canada Max Planck Inst Biol Cybernet Tubingen Germany Univ Minnesota Sch Med Ctr MR Res Minneapolis MN 55455 USA

Multivariate machine learning algorithms applied to human functional MRI (fMRI) data can decode information conveyed by cortical columns, despite the voxel-size being large relative to the width of columns. Several mechanisms have been proposed to underlie decoding of stimulus orientation or the stimulated eye. These include: (I) aliasing of high spatial-frequency components, including the main frequency component of the columnar organization, (II) contributions from local irregularities in the columnar organization, (III) contributions from large-scale non-columnar organizations, (IV) functionally selective veins with biased draining regions, and (V) complex spatio-temporal filtering of neuronal activity by fMRI voxels. Here we sought to assess the plausibility of two of the suggested mechanisms: (I) aliasing and (II) local irregularities, using a naive model of BOLD as blurring and MRI voxel sampling. To this end, we formulated a mathematical model that encompasses both the processes of imaging ocular dominance (OD) columns and the subsequent linear classification analysis. Through numerical simulations of the model, we evaluated the distribution of functional differential contrasts that can be expected when considering the pattern of cortical columns, the hemodynamic point spread function, the voxel size, and the noise. We found that with data acquisition parameters used at 3 Tesla, sub-voxel supra-Nyquist frequencies, including frequencies near the main frequency of the OD organization (0.5 cycles per mm), cannot contribute to the differential contrast. The differential functional contrast of local origin is dominated by low-amplitude contributions from low frequencies, associated with irregularities of the cortical pattern. Realizations of the model with parameters that reflected best-case scenario and the reported BOLD point-spread at 3 Tesla (3.5 mm) predicted decoding performances lower than those that have been previously obtained at this magnetic field str

关键词： Brain Mapping/methods Brain Mapping/methods Cerebral Cortex/physiology Humans image processing, computer-assisted/methods Magnetic Resonance Imaging Models, Neurological Models, Theoretical

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Spin-echo fMRI: The poor relation?

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NEUROimage 2012年第2期62卷 1109-1115页

作者： Norris, David G. UNESCO Weltkulturerbe Zollverein Erwin L Hahn Inst Magnet Resonance Imaging D-45141 Essen Germany Univ Twente MIRA Inst Biomed Technol & Tech Med NL-7500 AE Enschede Netherlands

Spin-echo fMRI offers a potentially better intrinsic functional spatial resolution than its gradient echo counterpart, as well as the elimination of signal dropouts in the image. This comes at the price of a significant loss in sensitivity. In this article the main methods for measuring spin-echo fMRI are presented: HASTE, SSFP, RASER and most importantly spin-echo EPI. Their relative merits and limitations are discussed. The BOLD contrast mechanisms responsible for spin echo fMRI are summarised, and the spatial origin of the signal within the neocortex discussed. The major publications concerning the use of spin echo fMRI are examined. At present the most promising application for this methodology would appear to be in the examination of cortical layers and columns. The balance of experimental and theoretical evidence accumulated to date leads the author to propose that: (i) There is little point in conducting spin-echo fMRI at main magnetic field strengths of 3 T and below;(ii) There are fundamental limitations to acquiring spin-echo BOLD data at 7 T and above;(iii) Whole brain coverage with SE-BOLD at very high static magnetic field strengths could prove valuable: and (iv) SE-BOLD is probably better suited to study cortical columns than cortical layers. Recently gradient-echo approaches for high spatial resolution fMRI have been demonstrated that employ special techniques to avoid the effects of larger post capillary vessels. The coming years will show whether spin-echo techniques can remain the method of choice for high spatial resolution studies, and whether they can extend their range of application at 7 T and above. (C) 2012 Elsevier Inc. All rights reserved.

关键词： Brain/physiology Brain Mapping/history Brain Mapping/history Brain Mapping/methods Brain Mapping/methods History, 20th Century History, 21st Century Humans image processing, computer-assisted/history image processing, computer-assisted/methods Magnetic Resonance Imaging/history Magnetic Resonance Imaging/methods Sensitivity and Specificity

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Whole brain quantitative T2 MRI across multiple scanners with dual echo FSE: Applications to AD, MCI, and normal aging

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NEUROimage 2010年第2期52卷 508-514页

作者： Bauer, Corinna M. Jara, Hernan Killiany, Ron Boston Univ Sch Med Dept Anat & Neurobiol Boston MA 02118 USA Boston Univ Sch Med Dept Radiol Boston Med Ctr Boston MA 02118 USA Boston Univ Dept Biomed Engn Boston MA 02215 USA Boston Univ Sch Med Ctr Biomed Imaging Boston MA 02118 USA Boston Univ Sch Publ Hlth Dept Environm Hlth Boston MA 02118 USA

The ability to pool data from multiple MRI scanners is becoming increasingly important with the influx in multi-site research studies. Fast spin echo (FSE) dual spin echo sequences are often chosen for such studies based principally on their short acquisition time and the clinically useful contrasts they provide for assessing gross pathology. The practicality of measuring FSE-T2 relaxation properties has rarely been assessed. Here, FSE-T2 relaxation properties are examined across the three main scanner vendors (General Electric (GE), Philips, and Siemens). The American College of Radiology (ACR) phantom was scanned on four 1.5 T platforms (two GE, one Philips, and one Siemens) to determine if the dual echo pulse sequence is susceptible to vendor-based variance. In addition, data from 85 subjects spanning the spectrum of normal aging, mild cognitive impairment (MCI), and Alzheimer's disease (AD) was obtained from the Alzheimer's Disease Neuroimaging Initiative (ADNI) to affirm the presence of any phantom based between vendor variance and determine the relationship between this variance and disease. FSE-T2 relaxation properties, including peak FSE-T2 and histogram width, were calculated for each phantom and human subject. Direct correspondence was found between the phantom and human subject data. Peak FSE-T2 of Siemens scanners was consistently at least 20 ms prolonged compared to GE and Philips. Siemens scanners showed broader FSE-T2 histograms than the other scanners. Greater variance was observed across GE scanners than either Philips or Siemens. FSE-T2 differences were much greater with scanner vendor than between diagnostic groups, as no significant changes in peak FSE-T2 or histogram width between normal aged, MCI, and AD subject groups were observed. These results indicate that whole brain histogram measures are not sensitive enough to detect FSE-T2 changes between normal aging, MCI, and AD and that FSE-T2 is highly variable across scanner vendors. (C) 2010 Els

关键词： Aged Aged, 80 and over Aging/pathology Algorithms Alzheimer Disease/pathology Brain/pathology Cognition Disorders/pathology Female Humans image processing, computer-assisted/instrumentation image processing, computer-assisted/methods Magnetic Resonance Imaging/instrumentation Magnetic Resonance Imaging/methods Male Middle Aged Phantoms, Imaging Severity of Illness Index Severity of Illness Index Time Factors

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Mapping anatomical correlations across cerebral cortex (MACACC) using cortical thickness from MRI

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NEUROimage 2006年第3期31卷 993-1003页

作者： Lerch, Jason P. Worsley, Keith Shaw, W. Philip Greenstein, Deanna K. Lenroot, Rhoshel K. Giedd, Jay Evans, Alan C. McGill Univ Montreal Neurol Inst McConnell Brain Imaging Ctr Montreal PQ H3A 2B4 Canada NIMH NIH Dept Hlth & Human Serv Bethesda MD 20892 USA

We introduce MACACC-Mapping Anatomical Correlations Across Cerebral Cortex-to study correlated changes within and across different cortical networks. The principal topic of investigation is whether the thickness of one area of the cortex changes in a statistically correlated fashion with changes in thickness of other cortical regions. We further extend these methods by introducing techniques to test whether different population groupings exhibit significantly varying MACACC patterns. The methods are described in detail and applied to a normal childhood development population (n = 292), and show that association cortices have the highest correlation strengths. Taking Brodmann Area (BA) 44 as a seed region revealed MACACC patterns strikingly similar to tractography maps obtained from diffusion tensor imaging. Furthermore, the MACACC map of BA 44 changed with age, older subjects featuring tighter correlations with BA 44 in the anterior portions of the superior temporal gyri. Lastly, IQ-dependent MACACC differences were investigated, revealing steeper correlations between BA 44 and multiple frontal and parietal regions for the higher IQ group, most significantly (t = 4.0) in the anterior cingulate. (c) 2006 Published by Elsevier Inc.

关键词： Adolescent Brain Mapping/methods Brain Mapping/methods Cerebral Cortex/anatomy & histology Child Child Development/physiology Dominance, Cerebral/physiology Female Frontal Lobe/anatomy & histology Humans image processing, computer-assisted/methods Imaging, Three-Dimensional/methods Intelligence/physiology Linear Models Magnetic Resonance Imaging/methods Male Mathematical Computing Nerve Net/anatomy & histology Parietal Lobe/anatomy & histology Software Statistics as Topic

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