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Measuring the hemodynamic response in chronic hypoperfusion

NEUROCASE 2006年第3期12卷 146-150页

作者： Fridriksson, Julius Rorden, Chris Morgan, Paul S. Morrow, K. Leigh Baylis, Gordon C. Univ S Carolina Dept Commun Sci & Disorders Columbia SC 29208 USA Univ Nottingham Dept Acad Radiol Nottingham NG7 2RD England Univ S Carolina Dept Psychol Columbia SC 29208 USA Med Univ S Carolina Brain Imaging Ctr Excellence Columbia SC USA

Although structural brain scans help assess brain injury in stroke, they cannot identify regions that are functionally disabled due to disrupted perfusion. Perfusion and functional MRI have the potential for determining the functional consequences of stroke. Here we examine the effectiveness of functional MRI to measure brain function in a single patient (LB) with chronic hypoperfusion. When LB made sustained hand movements we observed a sustained decrease in the fMRI signal, while normal individuals exhibit a sustained increase in signal while conducting this task. This work has clear implications for understanding stroke using functional MRI.

关键词： Brain Injuries/pathology Brain Injuries/pathology Brain Injuries/physiopathology Brain Injuries/physiopathology Cerebral Cortex/blood supply Cerebral Cortex/pathology Functional Laterality/physiology Hemodynamics/physiology Humans image processing, computer-assisted/methods Magnetic Resonance Imaging/methods Male Middle Aged Oxygen/blood Stroke/physiopathology

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Manganese-enhanced magnetic resonance imaging of mossy fiber plasticity in vivo

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NEUROimage 2006年第1期30卷 130-135页

作者： Nairismägi, J Pitkänen, A Narkilahti, S Huttunen, J Kauppinen, RA Gröhn, OHJ Univ Kuopio Dept Biomed NMR FIN-70211 Kuopio Finland Univ Kuopio Natl Bio NMR Facil Virtanen Inst Mol Sci FIN-70211 Kuopio Finland Univ Kuopio AI Virtanen Inst Mol Sci Epilepsy Res Lab FIN-70211 Kuopio Finland Univ Kuopio AI Virtanen Inst Mol Sci Dept Cognit Neurobiol FIN-70211 Kuopio Finland Kuopio Univ Hosp Dept Neurol SF-70210 Kuopio Finland Univ Birmingham Sch Sport & Exercise Sci Birmingham W Midlands England

Mn2+ -enhanced magnetic resonance imaging (MEMRI) was used to characterize activity-dependent plasticity in the moss), fiber pathway after intraperitoneal kainic acid (KA) injection. Enhancement of the MEMRI signal in the dentate gyrus and the CA3 subregion of the hippocampus was evident 3 to 5 days after injection of MnCl2 into the entorhinal cortex both in control and KA-injected rats. In volume-rendered three-dimensional reconstructions, Mn2+-induced signal enhancement revealed the extent of the mossy fiber pathway throughout the septotemporal axis of the dentate gyrus. An increase in the number of Mn2+ -enhanced pixels in the dentate gyrus and CA3 subfield of rats with KA injection correlated (P < 0.05) with histologically verified mossy fiber sprouting. These data demonstrate that MEMRI can be used to detect specific changes at the cellular level during activity-dependent plasticity in vivo. The present findings also suggest that MEMRI signal changes can serve as an imaging marker of epileptogenesis. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Animals Axons/ultrasonography Brain/anatomy & histology Brain Mapping Brain Mapping Chlorides/diagnostic use Dentate Gyrus/anatomy & histology Dominance, Cerebral/physiology Entorhinal Cortex/anatomy & histology image Enhancement/methods image processing, computer-assisted/methods Imaging, Three-Dimensional/methods Kainic Acid Magnetic Resonance Imaging/methods Male Manganese Compounds/diagnostic use Mossy Fibers, Hippocampal/ultrastructure Nerve Fibers/ultrastructure Nerve Net/anatomy & histology Nerve Regeneration/physiology Neural Pathways/anatomy & histology Neuronal Plasticity/physiology Neurons/ultrasonography Rats Thalamus/anatomy & histology

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White matter abnormalities in autism detected through transverse relaxation time imaging

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NEUROimage 2006年第4期29卷 1049-1057页

作者： Hendry, J DeVito, T Gelman, N Densmore, M Rajakumar, N Pavlosky, W Williamson, PC Thompson, PM Drost, DJ Nicolson, R Univ Western Ontario Dept Med Biophys London ON Canada Univ Western Ontario Dept Psychiat London ON N6A 3K7 Canada Univ Western Ontario Dept Diagnost Radiol & Nucl Med London ON N6A 3K7 Canada Univ Calif Los Angeles Sch Med Dept Neurol Lab Neuroimaging Los Angeles CA 90095 USA

While neuroimaging studies have reported neurobiological abnormalities in autism, the underlying tissue abnormalities remain unclear. Quantitative transverse relaxation time (T2) imaging permits the examination of tissue abnormalities in vivo, with increased T2 largely reflecting increased tissue water. Blood flow and the presence of tissue iron may also affect T2. In this study, we used voxel-based relaxometry of the cerebrum and global averages to examine T2 abnormalities in autism. Nineteen males with autism (age: 9.2 +/- 3.0 years) and 20 male controls (age: 10.7 +/- 2.9 years) underwent magnetic resonance imaging at 3.0 T. Quantitative T2 maps, generated through gradient echo sampling of the free induction decay and echo, were segmented into gray matter, white matter, and cerebrospinal fluid. Average cerebral gray and white matter T2 were determined and compared between groups. To assess localized T2 differences, the quantitative T2 maps were warped to a template created for this study, smoothed, and compared using statistical parametric mapping. Patients with autism had an increase in average cerebral white matter T2, although no group differences were seen in average cerebral gray matter T2. Patients with autism also had bilateral regional T2 increases in the gray matter and associated white matter of the parietal lobes (primary sensory association areas) and occipital lobes (visual association areas) and in the white matter within the supplementary motor areas in the frontal lobes. The regional and global elevations in white matter T2 suggest abnormalities of white matter tissue water content in autism, which may represent a neurobiological basis for the aberrant cortical connectivity hypothesized to underlie the disorder. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adolescent Autistic Disorder/diagnosis Autistic Disorder/physiopathology Blood-Brain Barrier/physiology Brain/pathology Brain/physiopathology Brain Mapping Brain Mapping Cerebral Cortex/abnormalities Cerebral Cortex/pathology Cerebral Cortex/physiopathology Cerebrospinal Fluid/physiology Child Dominance, Cerebral/physiology Humans image Enhancement/methods image processing, computer-assisted/methods Intelligence/physiology Magnetic Resonance Imaging/methods Magnetic Resonance Spectroscopy/methods Male Mathematical Computing Reference Values Statistics as Topic

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The internet analysis tools registry - A public resource for image analysis

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NEUROINFORMATICS 2006年第3期4卷 263-270页

作者： Kennedy, David N. Haselgrove, Christian Massachusetts Gen Hosp Dept Neurol Ctr Morphometr Anal Boston MA 02114 USA Massachusetts Gen Hosp Dept Radiol Boston MA 02114 USA

In this report, authors introduce the Internet Analysis Tools Registry(IATR). Instantiated as a web-accessible database (***. ***/iatr), this site isdevoted to facilitating image analysis tool sharing. This is accomplished by providing a forum fortool developers to describe available tools and enabling efficient searching of available tools fortool consumers. This resource, therefore, facilitates tool sharing by enabling more efficientconnection between developers, tools, and users. Asecondary benefit to this resource is thepotential to minimize overlap of tool development, provided that an existing tool for a specificneed that can be identified, reducing the need to develop redundant functionality merely for thelack of knowledge about other resources. Figure 1 shows the IATR homepage.

关键词： Brain/anatomy & histology Databases, Factual image processing, computer-assisted/methods Internet

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Comparison of 2D reconstructions of surgically excised subfoveal choroidal neovascularization with fluorescein angiographic features: SST report no. 15

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OPHTHALMOLOGY 2006年第2期113卷 267-279页

作者： Grossniklaus, HE Bressler, SB Miskala, PH Green, WR Bressler, NM Hawkins, BS Toth, CA Wilson, DJ Emory Eye Ctr LF Montgomery Ophthalm Pathol Lab Atlanta GA 30322 USA

Objectives: To compare topographic features of surgically excised subfoveal choroidal neovascularization with preoperative and postoperative fluorescein angiographic features from Submacular Surgery Trials (SST) patients, and to compare histological and angiographic features with preoperative and postoperative visual acuities (VAs). methods: Patients enrolled in the SST Groups N, B, and H trials between October 1999 and September 2001 and assigned to the surgery arm had surgically removed choroidal neovascularization sent to the SST Pathology Center. Grossly intact specimens were sectioned serially for 2-dimensional reconstruction and were assigned to growth pattern groups based on topographic mapping of the location of cellular components relative to the retinal pigment epithelium (RPE): sub-RPE, subretinal, combined, or indeterminate. These features were compared with preoperative fluorescein angiographic features. The histological choroidal neovascularization growth pattern was compared with preoperative VAs. Results: Two-dimensional reconstructions of surgically excised choroidal neovascularization could not be matched point for point to fluorescein angiographic features. Among the 52 specimens selected, the growth pattern could be determined by 2-dimensional reconstruction in 34 instances (65%), including 28 (80%) of 35 Group N specimens, 2 (40%) of 5 Group B specimens, and 4 (33%) of 12 Group H specimens. Among the choroidal neovascularization growth patterns that could be determined from specimens submitted, the majority of Group N specimens were combined, and the majority of Group H specimens were subretinal. In most instances for Group B specimens, the growth pattern was indeterminate. The postoperative abnormalities on fluorescein angiography were generally larger than measurements of excised specimens. The subretinal growth pattern was associated with the smallest decrease in 3-month postoperative average VA. Conclusions: Among the 52 specimens from the S

关键词： Adult Aged Aged, 80 and over Choroid/blood supply Choroidal Neovascularization/pathology Choroidal Neovascularization/surgery Clinical Trials as Topic Female Fluorescein Angiography Fovea Centralis Humans image processing, computer-assisted/methods Male Middle Aged Pigment Epithelium of Eye/pathology Visual Acuity

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Software for quantification of labeled bacteria from digital microscope images by automated image analysis

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BIOTECHNIQUES 2005年第6期39卷 859-863页

作者： Selinummi, J Seppälä, J Yli-Harja, O Puhakka, JA Tampere Univ Technol Inst Signal Proc FIN-33101 Tampere Finland

Automated image analysis software, CellC, was developed and validated for quantification of bacterial cells from digital microscope images. CellC enables automated enumeration of bacterial cells, comparison of total count and specific count images [e.g., 4',6-diamino-2-phenylindole (DAPI) and fluorescence in situ hybridization (FISH) images], and provides quantitative estimates of cell morphology. The software includes an intuitive graphical user interface that enables easy usage as well. as sequential analysis of multiple images without user intervention. Validation of enumeration reveals correlation to be better than 0.98 when total bacterial counts by CellC are compared with manual enumeration, with all validated image types. The software is freely available and modifiable: the executable files and MATLAB(R) source codes can be obtained at ***/sgn/csb/cellc.

关键词： Bioreactors Colony Count, Microbial/methods Colony Count, Microbial/methods image processing, computer-assisted/methods Microscopy Software

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Organic-inorganic hybrid liquid crystals:: Thermotropic mesophases formed by hybridization of liquid-crystalline phosphates and monodispersed α-Fe₂O₃ particles

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JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2005年第33期127卷 11578-11579页

作者： Kanie, K Muramatsu, A Tohoku Univ Inst Multidisciplinary Res Adv Mat Aoba Ku Sendai Miyagi 9808577 Japan

Nano-level hybridization of organic and inorganic materials has attracted agreat deal of attention,especially in the fields of material science and nanotechnology,because itis not rare to find unexpected superadditive *** liquid crystals (LCs) areanisotropic materials of an enormous variety of dynamic and self-assembling functions,and thus theintroduction of such functions into organic materials has been a useful technique in *** the other hand,recent progress of particle deposition systems,such as the gel-solmethod,enabled us to obtain mono-dispersed particles precisely controlled in size and *** the gel-sol method,we have reported a facile procedure for the preparation of monodispersedalpha-Fe_2O_3 particles with various shapes and sizes by the addition of shape controllers and *** example,in the presence of PO_4~(3-) ions,monodispersed spindle-type alpha-Fe_2O_3particles have been readily obtained.

关键词： Crystallization Ferrous Compounds/chemical synthesis Ferrous Compounds/chemical synthesis Ferrous Compounds/chemistry Ferrous Compounds/chemistry image processing, computer-assisted/methods Microscopy, Electron, Transmission/methods Nanostructures/chemistry Organometallic Compounds/chemical synthesis Organometallic Compounds/chemistry Particle Size Phosphates/chemical synthesis Phosphates/chemical synthesis Phosphates/chemistry Phosphates/chemistry Temperature

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Detection and automatic repair of nucleotide base-pair mutations by coherent light

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JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 2005年第41期127卷 14434-14438页

作者： Thanopulos, I Shapiro, M Univ British Columbia Dept Chem Vancouver BC V6T 1Z1 Canada Weizmann Inst Sci Dept Chem Phys IL-76100 Rehovot Israel

We show that phase-coherent optical techniques allow for the detection and automatic repair of mutations in nucleotide pairs. We demonstrate computationally that there is a laser pulse sequence that can detect the occurrence of a mutation caused by a double proton transfer between hydrogen-bonded nucleotide pairs and automatically repair it by converting the mutated nucleoticle pair to the nonmutated one. The specific system chosen for this demonstration is the hydrogen-bonded 2-pyridone-2-hydroxypyridine dimer at typical internucleotide distances, a well-established model for tautomeric acid base pairs.

关键词： Base Pairing/radiation effects computer Simulation DNA/chemistry DNA/radiation effects DNA Repair Hydrogen Bonding image processing, computer-assisted/methods Light Light Models, Chemical Mutation/radiation effects Nucleotides/chemistry Nucleotides/radiation effects Optics and Photonics Protons

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Integration of touch and sound in auditory cortex

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NEURON 2005年第2期48卷 373-384页

作者： Kayser, C Petkov, CI Augath, M Logothetis, NK Max Planck Inst Biol Cybernet D-72076 Tubingen Germany

To form a coherent percept of the environment, our brain combines information from different senses. Such multisensory integration occurs in higher association cortices;but supposedly, it also occurs in early sensory areas. Confirming the latter hypothesis, we unequivocally demonstrate supra-additive integration of touch and sound stimulation at the second stage of the auditory cortex. Using high-resolution fMRI of the macaque monkey, we quantified the integration of auditory broad-band noise and tactile stimulation of hand and foot in anaesthetized animals. Integration was found posterior to and along the lateral side of the primary auditory cortex in the caudal auditory belt. Integration was stronger for temporally coincident stimuli and obeyed the principle of inverse effectiveness: greater enhancement for less effective stimuli. These findings demonstrates that multisensory integration occurs early and close to primary sensory areas and-because it occurs in anaesthetized animals-suggests that this integration is mediated by preattentive bottom-up mechanisms.

关键词： Animals Auditory Cortex/blood supply Auditory Cortex/physiology Auditory Perception/physiology Behavior, Animal Brain Mapping Brain Mapping image processing, computer-assisted/methods Macaca mulatta Magnetic Resonance Imaging/methods Oxygen/blood Physical Stimulation/methods Sound Sound Touch/physiology

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Formal learning theory dissociates brain regions with different temporal integration

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NEURON 2005年第2期47卷 295-306页

作者： Gläscher, J Büchel, C Nord, N Univ Hamburg Med Ctr Hamburg Eppendorf Dept Syst Neurosci D-20246 Hamburg Germany

Learning can be characterized as the extraction of reliable predictions about stimulus occurrences from past experience. In two experiments, we investigated the interval of temporal integration of previous learning trials in different brain regions using implicit and explicit Pavlovian fear conditioning with a dynamically changing reinforcement regime in an experimental setting. With formal learning theory (the Rescorla-Wagner model), temporal integration is characterized by the learning rate. Using fMRI and this theoretical framework, we are able to distinguish between learning-related brain regions that show long temporal integration (e.g., amygdala) and higher perceptual regions that integrate only over a short period of time (e.g., fusiform face area, parahippocampal place area). This approach allows for the investigation of learning-related changes in brain activation, as it can dissociate brain areas that differ with respect to their integration of past learning experiences by either computing long-term outcome predictions or instantaneous reinforcement expectancies.

关键词： Adult Brain/anatomy & histology Brain/blood supply Brain/physiology Brain Mapping Brain Mapping Conditioning, Classical Fear Functional Laterality Galvanic Skin Response/physiology Humans image processing, computer-assisted/methods Learning/physiology Magnetic Resonance Imaging/methods Male Memory, Short-Term/physiology Models, Neurological Nonlinear Dynamics Oxygen/blood Photic Stimulation Predictive Value of Tests Psychomotor Performance/physiology Regression Analysis Reinforcement (Psychology)

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