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The neural substrate of the ideomotor principle: An event-related fMRI analysis

NEUROimage 2008年第3期39卷 1274-1288页

作者： Melcher, Tobias Weidema, Maaike Eenshuistra, Rena M. Hommel, Bernhard Gruber, Oliver Univ Gottingen Syst Neurosci Unit Dept Psychiat & Psychotherapy D-37075 Gottingen Germany Leiden Univ Inst Psychol Res NL-2300 RA Leiden Netherlands Leiden Inst Brain & Cognit Leiden Netherlands

The present fMRI study sought to investigate the neural basis of perceiving learned action effects and thereby to test for hypotheses based on the ideomotor principle. For this purpose, we had subjects undergo a two-phase experimental procedure comprising an acquisition and a test phase, the latter administered inside the MR scanner. During the acquisition phase, free-choice button presses were contingently followed by one of two tones of different pitch which thereby should become "learned action effects". During the following test phase, subjects were presented with the action effects either when in a passive (non-acting) state or when they carried out forced-choice button presses. Conform to our expectations, we found evidence for a motor effector activation following the passive perception of effect tones which elicited activation in the neural motor system (premotor and somatosensory cortices, SMA, and cerebellum). Surprisingly, however, this activation was observed for left-hand effect tones only, suggesting a basic asymmetry in the impact of ideomotor learning. Moreover, we found activation in the posterior prefrontal and temporo-parietal cortex in response to action effects during the pursuit of goal-directed action. This suggests that action effects attracted special attention and thereby engaged selective cognitive control processes to ensure task-appropriate performance. Finally, there was reduced premotor activation for response-compatible as compared to response-incompatible action effects which can be taken as indication for differential requirements on the motor system and thus for behavioral interference and/or facilitation by learned action effects. (c) 2007 Elsevier Inc. All rights reserved.

关键词： Acoustic Stimulation Adult Cerebral Cortex/physiology Color Perception/physiology Conflict (Psychology) Data Interpretation, Statistical Evoked Potentials/physiology Female Functional Laterality/physiology Humans image processing, computer-assisted/methods Learning/physiology Magnetic Resonance Imaging/statistics & numerical data Male Movement/physiology Photic Stimulation Psychomotor Performance/physiology Visual Cortex/physiology

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Structure of the oligosaccharyl transferase complex at 12 Å resolution

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STRUCTURE 2008年第3期16卷 432-440页

作者： Li, Hua Chavan, Manasi Schindelin, Hermann Lennarz, William J. Li, Huilin SUNY Stony Brook Inst Cell & Dev Biol Stony Brook NY 11794 USA SUNY Stony Brook Dept Biochem Stony Brook NY 11794 USA Brookhaven Natl Lab Dept Biol Upton NY 11973 USA Univ Wurzburg Inst Biol Struct D-97078 Wurzburg Germany Univ Wurzburg Rudolf Virchow Ctr Expt Biomed D-97078 Wurzburg Germany

Oligosaccharyl transferase (OT) catalyzes the transfer of a lipid-linked oligosaccharide to the nascent polypeptide emerging from the translocon. Currently, there is no structural information on the membrane-embedded OT complex, which consists of eight different polypeptide chains. We report a 12 angstrom resolution cryo-electron microscopy structure of OT from yeast. We mapped the locations of four essential OT subunits through a maltose-binding protein fusion strategy. OT was found to have a large domain in the lumenal side of encloplasmic reticulum where the catalysis occurs. The lumenal domain mainly comprises the catalytic Stt3p, the donor substrate-recognizing Wbp1p, and the acceptor substrate-recognizing Ost1p. A prominent groove was observed between these subunits, and we propose that the nascent polypepticle from the translocon threads through this groove while being scanned by the Ost1p subunit for the presence of the glycosylation sequon.

关键词： Carrier Proteins/genetics Cloning, Molecular Cryoelectron Microscopy Digitonin/pharmacology Hexosyltransferases/chemistry Hexosyltransferases/genetics Hexosyltransferases/metabolism image processing, computer-assisted/methods Imaging, Three-Dimensional Membrane Proteins/chemistry Membrane Proteins/genetics Membrane Proteins/metabolism Models, Biological Models, Molecular Molecular Weight Multiprotein Complexes/chemistry Protein Subunits/chemistry Recombinant Fusion Proteins/chemistry Recombinant Fusion Proteins/genetics Solubility/drug effects Yeasts/enzymology

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Different dynamics of performance and brain activation in the time course of perceptual learning

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NEURON 2008年第6期57卷 827-833页

作者： Yotsumoto, Yuko Watanabe, Takeo Sasaki, Yuka Massachusetts Gen Hosp Athinoula A Martinos Ctr Biomed Imaging Dept Radiol Charlestown MA 02129 USA Boston Univ Dept Psychol Boston MA 02215 USA CALTECH ERATO Shimojo Implicit Brain Funct Project Pasadena CA 91125 USA Harvard Univ Sch Med Dept Radiol Boston MA 02115 USA

Perceptual learning is regarded as a manifestation of experience-dependent plasticity in the sensory systems, yet the underlying neural mechanisms remain unclear. We measured the dynamics of performance on a visual task and brain activation in the human primary visual cortex (V1) across the time course of perceptual learning. Within the first few weeks of training, brain activation in a V1 subregion corresponding to the trained visual field quadrant and task performance both increased. However, while performance levels then saturated and were maintained at a constant level, brain activation in the corresponding areas decreased to the level observed before training. These findings indicate that there are distinct temporal phases in the time course of perceptual learning, related to differential dynamics of BOLD activity in visual cortex.

关键词： Adult Female Humans image processing, computer-assisted/methods Learning/physiology Magnetic Resonance Imaging/methods Male Nonlinear Dynamics Oxygen/blood Pattern Recognition, Visual/physiology Photic Stimulation/methods Time Factors Visual Cortex/blood supply Visual Cortex/physiology Visual Fields/physiology

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Template-O-Matic: A toolbox for creating customized pediatric templates

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NEUROimage 2008年第3期41卷 903-913页

作者： Wilke, Marko Holland, Scott K. Altaye, Mekibib Gaser, Christian Univ Tubingen Childrens Hosp Dept Pediat Neurol & Dev Med D-72076 Tubingen Germany Univ Tubingen Dept Neuroradiol CNS Sect Expt MR Tubingen Germany Childrens Hosp Med Ctr Imaging Res Ctr Cincinnati OH 45229 USA Univ Cincinnati Dept Pediat Cincinnati OH 45221 USA Univ Jena Dept Psychiat D-6900 Jena Germany

processing pediatric neuroimaging data is a challenge due to pervasive morphological changes that occur in the human brain during normal development. This is of special relevance when reference data is used as part of the processing approach, as in spatial normalization and tissue segmentation. Current approaches construct reference data (templates) by averaging brain images from a control group of subjects, or by creating custom templates from the group under study. In this technical note, we describe a new, and generalized method of constructing such appropriate reference data by statistically analyzing a large sample (n= 404) of healthy children, as acquired during the NIH MRI study of normal brain development. After eliminating non-contributing demographic variables, we modeled the effects of age (first, second, and third-order terms) and gender, for each voxel in gray matter and white matter. By appropriate weighting with the parameter estimates from these analyses, complete tissue maps can be generated automatically from this database to match a pediatric population selected for study. The algorithm is implemented in the form of a toolbox for the SPM5 image data processing suite, which we term Template-O-Matic. We compare the performance of this approach with the current method of template generation and discuss the implications of our approach. (C) 2008 Elsevier Inc. All rights reserved.

关键词： Adolescent Algorithms Brain/anatomy & histology Child Humans image processing, computer-assisted/methods image processing, computer-assisted/standards Magnetic Resonance Imaging Reference Standards

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Improving 2D-DIGE protein expression analysis by two-stage linear mixed models: assessing experimental effects in a melanoma cell study

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BIOINFORMATICS 2008年第23期24卷 2706-2712页

作者： Fernandez, Elmer A. Girotti, Maria R. Lopez del Olmo, Juan A. Llera, Andrea S. Podhajcer, Osvaldo L. Cantet, Rodolfo J. C. Balzarini, Monica Catholic Univ Sch Engn Intelligent Data Anal Grp Cordoba Argentina Consejo Nacl Invest Cient & Tecn Cordoba Argentina Fdn Inst Leloir Lab Mol & Cellular Therapy Buenos Aires DF Argentina Ctr Nacl Invest Cardiovasc Unidad Prote Madrid Spain Univ Buenos Aires Fac Agron Buenos Aires DF Argentina Natl Univ Cordoba Biometr Dept Cordoba Argentina

Motivation: Difference in-gel electrophoresis (DIGE)-based protein expression analysis allows assessing the relative expression of proteins in two biological samples differently labeled (Cy5, Cy3 CyDyes). In the same gel, a reference sample is also used (Cy2 CyDye) for spot matching during image analysis and volume normalization. The standard statistical techniques to identify differentially expressed (DE) proteins are the calculation of fold-changes and the comparison of treatment means by the t-test. The analyses rarely accounts for other experimental effects, such as CyDye and gel effects, which could be important sources of noise while detecting treatment effects. Results: We propose to identify DIGE DE proteins using a two-stage linear mixed model. The proposal consists of splitting the overall model for the measured intensity into two interconnected models. First, we fit a normalization model that accounts for the general experimental effects, such as gel and CyDye effects as well as for the features of the associated random term distributions. Second, we fit a model that uses the residuals from the first step to account for differences between treatments in protein-by-protein basis. The modeling strategy was evaluated using data from a melanoma cell study. We found that a heteroskedastic model in the first stage, which also account for CyDye and gel effects, best normalized the data, while allowing for an efficient estimation of the treatment effects. The Cy2 reference channel was used as a covariate in the normalization model to avoid skewness of the residual distribution. Its inclusion improved the detection of DE proteins in the second stage.

关键词： Carbocyanines/chemistry Cell Line, Tumor Computational Biology/methods Electrophoresis, Gel, Two-Dimensional/instrumentation Electrophoresis, Gel, Two-Dimensional/methods Fluorescent Dyes/chemistry Humans image processing, computer-assisted/methods Linear Models Melanoma/metabolism Proteome/metabolism Proteomics/methods

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Accurate prediction of V1 location from cortical folds in a surface coordinate system

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NEUROimage 2008年第4期39卷 1585-1599页

作者： Hinds, Oliver P. Rajendran, Niranjini Polimeni, Jonathan R. Augustinack, Jean C. Wiggins, Graham Wald, Lawrence. L. Rosas, H. Diana Potthast, Andreas Schwartz, Eric L. Fischl, Bruce Boston Univ Dept Cognit & Neural Syst Boston MA 02215 USA Harvard Univ Sch Med MGH Dept RadiolAthinoula A Martinos Ctr Cambridge MA 02138 USA Harvard Univ Sch Med MGH Dept NeurolAthinoula A Martinos Ctr Cambridge MA 02138 USA Siemens Med Solut Inc Malvern PA USA Boston Univ Dept Elect & Comp Engn Boston MA 02215 USA Boston Univ Sch Med Dept Anat & Neurobiol Boston MA 02215 USA MIT Comp Sci & Artificial Intelligence Lab Cambridge MA 02139 USA

Previous studies demonstrated substantial variability of the location of primary visual cortex (V1) in stereotaxic coordinates when linear volume-based registration is used to match volumetric image intensities [Amunts, K., Malikovic, A., Mohlberg, H., Schormann, T., and Zilles, K. (2000). Brodmann's areas 17 and 18 brought into stereotaxic space-where and how variable? Neurohnage, 11(1):66-84]. However, other qualitative reports of V1 location [Smith, G. (1904). The morphoiogy of the occipital region of the cerebral hemisphere in man and the apes. Anatomischer Anzeiger, 24:436-451;Stensaas, S.S., Eddington, D.K., and Dobelle, W.H. (1974). The topography and variability of the primary visual cortex in man. J Neurosurg, 40(6):747-755;Rademacher, J., Caviness, V.S., Steinmetz, H., and Galaburda, A.M. (1993). Topographical variation of the human primary cortices: implications for neuroimaging, brain mapping, and neurobiology. Cereb Cortex, 3 (4):313-329] suggested a consistent relationship between V1 and the surrounding cortical folds. Here, the relationship between folds and the location of V1 is quantified using surface-based analysis to generate a probabilistic atlas of human V1. High-resolution (about 200 pm) magnetic resonance imaging (MRI) at 7 T of ex vivo human cerebral hemispheres allowed identification of the full area via the stria of Gennari: a myeloarchitectonic feature specific to V1. Separate, whole-brain scans were acquired using MRI at 1.5 T to allow segmentation and mesh reconstruction of the cortical gray matter. For each individual, V1 was manually identified in the high-resolution volume and projected onto the cortical surface. Surface-based intersubject registration [Fischl, B., Screno, M.I., Tootell, R.B., and Dale, A.M. (1999b). High-resolution intersubject averaging and a coordinate system for the cortical surface. Haiti Brain Mapp, 8(4):272-84] was performed to align the primary cortical folds of individual hemispheres to those of a reference

关键词： Aged Algorithms Autopsy Autopsy Cerebral Cortex/anatomy & histology Female Functional Laterality/physiology Humans image processing, computer-assisted/methods image processing, computer-assisted/statistics & numerical data Magnetic Resonance Imaging Male Middle Aged Models, Statistical Predictive Value of Tests Stereotaxic Techniques Visual Cortex/anatomy & histology

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Tensor-based morphometry as a neuroimaging biomarker for Alzheimer's disease: An MRI study of 676 AD, MCI, and normal subjects

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NEUROimage 2008年第3期43卷 458-469页

作者： Hua, Xue Leow, Alex D. Parikshak, Neelroop Lee, Suh Chiang, Ming-Chang Toga, Arthur W. Jack, Clifford R., Jr. Weiner, Michael W. Thompson, Paul M. Univ Calif Los Angeles Sch Med Dept Neurol Lab Neuro Imaging Los Angeles CA 90095 USA Mayo Clin Coll Med Rochester MN USA UC San Francisco Dept Radiol San Francisco CA USA UC San Francisco Dept Med & Psychiat San Francisco CA USA Dept Vet Affairs Med Ctr Los Angeles CA USA

In one of the largest brain MRI studies to date, we used tensor-based morphometry (TBM) to create 3D maps of structural atrophy in 676 subjects with Alzheimer's disease (AD), mild cognitive impairment (MCI), and healthy elderly controls, scanned as part of the Alzheimer's Disease Neuroimaging Initiative (ADNI). Using inverse-consistent 3D non-linear elastic image registration, we warped 676 individual brain MRI volumes to a population mean geometric template. Jacobian determinant maps were created, revealing the 3D pro. le of local volumetric expansion and compression. We compared the anatomical distribution of atrophy in 165 AD patients (age: 75.6 +/- 7.6 years), 330 MCI subjects (74.8 +/- 7.5), and 181 controls (75.9 +/- 5.1). Brain atrophy in selected regions-of-interest was correlated with clinical measurements - the sum-of-boxes clinical dementia rating (CDR-SB), mini-mental state examination (MMSE), and the logical memory test scores - at voxel level followed by correction for multiple comparisons. Baseline temporal lobe atrophy correlated with current cognitive performance, future cognitive decline, and conversion from MCI to AD over the following year;it predicted future decline even in healthy subjects. Over half of the AD and MCI subjects carried the ApoE4 (apolipoprotein E4) gene, which increases risk for AD;they showed greater hippocampal and temporal lobe deficits than non-carriers. ApoE2 gene carriers - 1/6 of the normal group - showed reduced ventricular expansion, suggesting a protective effect. As an automated image analysis technique, TBM reveals 3D correlations between neuroimaging markers, genes, and future clinical changes, and is highly efficient for large-scale MRI studies. Published by Elsevier Inc.

关键词： Aged Alzheimer Disease/genetics Alzheimer Disease/pathology Apolipoprotein E4/genetics Brain/pathology Brain Mapping/methods Brain Mapping/methods Disease Progression Humans image processing, computer-assisted/methods Magnetic Resonance Imaging Neuropsychological Tests

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A Potential Reference Point for Assessment of Condylar Bone Marrow of the Temporomandibular Joint On Proton Density Weighted images

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CRANIO-THE JOURNAL OF CRANIOMANDIBULAR & SLEEP PRACTICE 2008年第4期26卷 248-254页

作者： Yamamoto, Aya Sano, Tsukasa Otonari-Yamamoto, Mika Nishikawa, Keiichi Kwok, Edmund Tokyo Dent Coll Dept Oral & Maxillofacial Radiol Mihama Ku Chiba 2618502 Japan Univ Rochester Rochester NY 14627 USA

The purpose of this research was to determine a potential reference point for measurement of signal intensity of bone marrow of the condyle on proton density-weighted images (PDW) prior to analysis of bone marrow abnormality related to symptomatic osteoarthritis of the temporomandibular joint (TMJ). The study was based on 79 joints in 41 patients. The regions of interest (ROI) were placed over the bone marrow of the condyle and four other structures. It was hypothesized that a correlation between signal intensity of ROI over bone marrow and that of another structure would provide a potential reference point for measurement of signal intensity of bone marrow. A significant positive linear correlation was found in the group for gray matter-1 and bone marrow. The correlation coefficient was 0.3 (Pearson correlation coefficient;p<0.05). It was determined that gray matter is a potential reference point in evaluating the signal intensity of bone marrow in the mandibular condyle.

关键词： Adult Bone Marrow/pathology Brain/pathology Dislocations/diagnosis Dislocations/diagnosis Female Humans image processing, computer-assisted/methods Magnetic Resonance Imaging/methods Male Mandibular Condyle/pathology Osteoarthritis/diagnosis Osteophyte/diagnosis Parotid Gland/pathology Pterygoid Muscles/pathology Temporomandibular Joint Disk/pathology Temporomandibular Joint Disorders/diagnosis

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Relationship between retinal nerve fiber layer measurement and signal strength in optical coherence tomography

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OPHTHALMOLOGY 2008年第8期115卷 1347-1351页

作者： Cheung, Carol Yim Lui Leung, Christopher Kai Shun Lin, Dusheung Pang, Chi-Pui Lam, Dennis Shun Chiu Chinese Univ Hong Kong Dept Ophthalmol & Visual Sci Hong Kong Eye Hosp Kowloon Hong Kong Peoples R China Univ Calif San Diego Hamilton Glaucoma Ctr La Jolla CA 92093 USA Shantou Univ Coll Med Joint Shantou Int Eye Ctr Shantou Peoples R China

Purpose: To examine the relationship between signal strength and retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT). Design: Observational cross-sectional study. Participants: Forty normal subjects were recruited. methods: Retinal nerve fiber layer (RNFL) thickness was measured by Stratus OCT (Carl Zeiss Meditec, Dublin, CA). In each eye, the focusing knob was adjusted to obtain 6 images with different signal strengths ranging from 5 to 10. The relationships between signal strength and RNFL thickness were examined using the Spearman correlation coefficient. The differences of RNFL thicknesses were compared with repeated-measures analysis of variance. Main Outcome Measures: Retinal nerve fiber layer thicknesses measured at different signal strengths. Results: Significant differences were observed between measurements obtained at signal strength of 10 and those obtained with signal strength of less than 10 at the superior, nasal, and temporal clock hours. RNFL thickness generally increased with the signal strength, with significant correlations found with the total average, superior, and nasal clock hours RNFL thicknesses. Conclusions: Optical coherence tomography RNFL measurements vary significantly with signal strength. Obtaining the maximal possible signal strength is recommended for RNFL thickness measurement.

关键词： Adult Aged Cross-Sectional Studies Female Glaucoma/diagnosis Humans image processing, computer-assisted/methods Male Middle Aged Nerve Fibers Ocular Hypertension/diagnosis Optic Disk/anatomy & histology Optic Nerve Diseases/diagnosis Retinal Ganglion Cells/cytology Tomography, Optical Coherence/methods Tomography, Optical Coherence/methods Visual Fields

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Characterizing the spatio-temporal behavior of cell populations through image autoand cross-correlation microscopy

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BIOTECHNIQUES 2007年第1期43卷 107-115页

作者： Bonnet, Noeel Delavoie, Franck Zahm, Jean-Marie Univ Reims UMR 514 INSERM U514 F-51092 Reims France

We propose two methods for characterizing the spatio-temporal behavior of cell populations in culture. The first method, image auto-correlation microscopy (IACM), allows us to characterize the variation in the number of objects as a function of time, thus enabling the quantification of the clustering properties of cell populations to be performed. The second method, image crosscorrelation microscopy (ICCM), allows us to characterize the migration properties of cell populations. The latter method does not require estimation or measurement of the trajectories of individual cells, which is very demanding when populations of >100 cells are examined. The capabilities of the two methods are demonstrated with simulated cell populations, and their usefulness is illustrated with experiments involving invasive and noninvasive tumor cell populations.

关键词： Animals Catechin/analogs & derivatives Catechin/pharmacology Cell Aggregation/drug effects Cell Line Cell Movement/drug effects Cell Survival/drug effects Cells/cytology computer Simulation Humans image processing, computer-assisted/methods Mice Microscopy/methods Neoplasms/pathology Time Factors

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