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Encoding the identity and location of objects in human LOC

NEUROimage 2011年第3期54卷 2297-2307页

作者： Cichy, Radoslaw Martin Chen, Yi Haynes, John-Dylan Charite Bernstein Ctr Computat Neurosci D-10115 Berlin Germany Berlin Sch Mind & Brain Berlin Germany Max Planck Inst Human Cognit & Brain Sci Leipzig Germany

We are able to recognize objects independent of their location in the visual field. At the same time, we also keep track of the location of objects to orient ourselves and to interact with the environment. The lateral occipital complex (LOC) has been suggested as the prime cortical region for representation of object identity. However, the extent to which LOC also represents object location has remained debated. In this study we used high-resolution fMRI in combination with multivoxel pattern classification to investigate the cortical encoding of three object exemplars from four different categories presented in two different locations. This approach allowed us to study location-tolerant object information and object-tolerant location information in LOC, both at the level of categories and exemplars. We found evidence for both location-tolerant object information and object-tolerant location information in LOC at the level of categories and exemplars. Our results further highlight the mixing of identity and location information in the ventral visual pathway. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Adult Female Form Perception/physiology Generalization (Psychology) Humans image processing, computer-assisted Linear Models Magnetic Resonance Imaging Male Occipital Lobe/physiology Photic Stimulation Space Perception/physiology Visual Pathways/physiology Young Adult

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Automated Measurement Method and Tool of Glomerular Filtration Rate Using Triphasic Helical Computed Tomography images

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UROLOGY 2011年第5期77卷 1259-1264页

作者： Li, Hong Janosko, Edward Gong, Jianping Cai, Qing Geng, Ping Kang, Yan Northeastern Univ Sino Dutch Biomed & Informat Engn Sch Shenyang Liaoning Peoples R China Atlantic Urol Wilmington NC USA Soochow Univ Affiliated Hosp 2 Dept Radiol Suzhou Peoples R China Northeastern Univ Coll Sci Shenyang Liaoning Peoples R China

OBJECTIVES To introduce an automated method to perform computed tomography-based glomerular filtration rate (CT GFR) measurement using the 2-point Patlak plot technique and triphasic helical CT images. We also evaluated the correlation between our automated method and the manual measurement results, as well as the results from cystatin C. METHODS The present study included 25 patients without an acute renal disorder. The CT scan protocol consisted of an unenhanced CT examination followed by 2 contrast-enhanced CT examinations in the arterial and parenchymal phase. Between the noncontrast scan and the arterial scan, 7 dynamic scans were obtained to provide more data on the arterial input function. The 2-point Patlak plot technique was used in the automated and manual measurement methods. For each patient, the cystatin C level, determined in blood samples, was used as a reference. RESULTS The correlation between our automated method and the cystatin C method in 25 patients was 0.8029 (P < .001). The correlation between the manually implemented CT GFR method and the cystatin C method was 0.8287 (P < .001). A strong correlation (r = .9518, P < .001) was seen between the automated and manual measurements using the same model;however, the automated process can be finished within 2 minutes. CONCLUSIONS The automated CT GFR measurement method could potentially be used because of its highly improved efficiency. Moreover, it would avoid the use of a differential renal nuclear study. This would be helpful for predicting the residual GFR after nephrectomy and could also be used to predict the residual GFR after partial nephrectomy for tumor or stone treatment. UROLOGY 77: 1259-1264, 2011. (C) 2011 Elsevier Inc.

关键词： Adult Aged Female Glomerular Filtration Rate Humans image processing, computer-assisted Kidney Function Tests/methods Male Middle Aged Tomography, Spiral Computed Young Adult

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Fractional anisotropy of cerebral white matter and thickness of cortical gray matter across the lifespan

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NEUROimage 2011年第1期58卷 41-49页

作者： Kochunov, P. Glahn, D. C. Lancaster, J. Thompson, P. M. Kochunov, V. Rogers, B. Fox, P. Blangero, J. Williamson, D. E. Univ Maryland Maryland Psychiat Res Ctr Catonsville MD 21228 USA Univ Texas Hlth Sci Ctr San Antonio Res Imaging Inst San Antonio TX 78229 USA SW Fdn Biomed Res San Antonio TX USA Yale Univ Dept Psychiat New Haven CT 06520 USA Univ Calif Los Angeles Sch Med Lab Neuro Imaging Los Angeles CA USA Univ Texas Hlth Sci Ctr San Antonio Dept Psychiat San Antonio TX 78229 USA Univ Texas Hlth Sci Ctr San Antonio Dept Epidemiol & Biostat San Antonio TX 78229 USA

We examined age trajectories of fractional anisotropy (FA) of cerebral white matter (WM) and thickness of cortical gray matter (GM) in 1031 healthy human subjects (aged 11-90 years). Whole-brain FA and GM thickness values followed quadratic trajectories with age but the relationship between them was linear, indicating that a putative biological mechanism may explain the non-linearity of their age trajectories. Inclusion of the FA values into the quadratic model of the whole-brain and regional GM thickness changes with age made the effect of the age(2) term no longer significant for the whole-brain GM thickness and greatly reduced its significance for regional GM thickness measurements. The phylogenetic order of cerebral myelination helped to further explain the intersubject variability in GM thickness. FA values for the early maturing WM were significantly better (p = 10(-6)) at explaining variability in GM thickness in maturing (aged 11-20) subjects than FA values for the late maturing WM. The opposite trend was observed for aging subjects (aged 40-90) where FA values for the late maturing WM were better (p = 10(-16)) at explaining the variability in GM thickness. We concluded that the non-linearity of the age trajectory for GM thickness, measured from TI-weighted MRI, was partially explained by the heterogeneity and the heterochronicity of the age-related changes in the microintegrity of cerebral WM. We consider these findings as the evidence that the measurements of age-related changes in GM thickness and FA are driven, in part, by a common biological mechanism, presumed to be related to changes in cerebral myelination. (C) 2011 Elsevier Inc. All rights reserved.

关键词： Adolescent Adult Aged Aged, 80 and over Aging/physiology Algorithms Anisotropy Cerebral Cortex/anatomy & histology Cerebral Cortex/growth & development Child Data Interpretation, Statistical Diffusion Tensor Imaging Diffusion Tensor Imaging Female Humans image processing, computer-assisted Male Middle Aged Myelin Sheath/physiology Nerve Fibers/physiology Neural Pathways/anatomy & histology Neural Pathways/growth & development Pyramidal Tracts/anatomy & histology Pyramidal Tracts/growth & development Young Adult

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A Common, High-Dimensional Model of the Representational Space in Human Ventral Temporal Cortex

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NEURON 2011年第2期72卷 404-416页

作者： Haxby, James V. Guntupalli, J. Swaroop Connolly, Andrew C. Halchenko, Yaroslav O. Conroy, Bryan R. Gobbini, M. Ida Hanke, Michael Ramadge, Peter J. Dartmouth Coll Dept Psychol & Brain Sci Hanover NH 03755 USA Univ Trento Ctr Mind Brain Sci I-38068 Rovereto Italy Princeton Univ Dept Elect Engn Princeton NJ 08544 USA Univ Bologna Dipartimento Psicol I-40127 Bologna Italy

We present a high-dimensional model of the representational space in human ventral temporal (VT) cortex in which dimensions are response-tuning functions that are common across individuals and patterns of response are modeled as weighted sums of basis patterns associated with these response tunings. We map response-pattern vectors, measured with fMRI, from individual subjects' voxel spaces into this common model space using a new method, "hyperalignment." Hyperalignment parameters based on responses during one experiment-movie viewing-identified 35 common response-tuning functions that captured fine-grained distinctions among a wide range of stimuli in the movie and in two category perception experiments. Between-subject classification (BSC, multivariate pattern classification based on other subjects' data) of response-pattern vectors in common model space greatly exceeded BSC of anatomically aligned responses and matched within-subject classification. Results indicate that population codes for complex visual stimuli in VT cortex are based on response-tuning functions that are common across individuals.

关键词： Adult Brain Mapping/methods Brain Mapping/methods Functional Neuroimaging Humans image processing, computer-assisted Models, Neurological Neurons/physiology Photic Stimulation Temporal Lobe/physiology Visual Cortex/physiology Visual Perception/physiology

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Neurobiological substrate of smoking-related attentional bias

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NEUROimage 2011年第3期54卷 2374-2381页

作者： Luijten, Maartje Veltman, Dick J. van den Brink, Wim Hester, Rob Field, Matt Smits, Marion Franken, Ingmar. H. A. Erasmus Univ Inst Psychol NL-3000 DR Rotterdam Netherlands Erasmus MC Univ Med Ctr Rotterdam Dept Radiol NL-3000 CA Rotterdam Netherlands Univ Amsterdam Acad Med Ctr Dept Psychiat Amsterdam Inst Addict Res NL-1105 AZ Amsterdam Netherlands Univ Melbourne Dept Psychol Sci Melbourne Vic 3010 Australia Univ Liverpool Sch Psychol Liverpool L69 7ZA Merseyside England

Substance-dependent patients automatically and involuntarily allocate their attention to drug cues in the environment, a process referred to as attentional bias. Attentional bias is increased during periods of subjective craving and predictive of treatment outcome and relapse in substance dependence. Despite recent theoretical and clinical advances with regard to attentional bias, the underlying neurobiological mechanisms are largely unknown. The objective of the current study was to investigate the neural substrate of attentional bias and associated subjective craving in smokers. A group of smokers (n = 20) and a group of age- and gender-matched nonsmoking controls (n = 22) were recruited from the general population and participated in a single session of fMRI scanning while attentional processes were manipulated. Main outcome measures were blood oxygen level-dependent (BOLD) fMRI activation during an attentional bias paradigm and self-reported cigarette craving. Results of the current study show that the dorsal anterior cingulate cortex, the superior parietal gyrus, and the superior temporal gyrus were more strongly activated in smokers, as compared to controls, when they had to pay attention to task-relevant information (line counting) while smoking cues were present as distracters (attentional bias). Subjective craving measures during attentional bias correlated with brain activation in the insula and putamen. To our knowledge, this is the first controlled study that shows the brain regions involved in attentional bias in smokers. The current study demonstrates that brain regions contributing to top-down attentional processing are implicated in attentional bias in smokers, suggesting that smokers have to employ more attentional resources to focus on a standard cognitive task when smoking cues are present. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Adult Attention/physiology Brain/physiology Brain Mapping Brain Mapping Breath Tests Cerebral Cortex/physiology Cues Female Frontal Lobe/physiology Humans image processing, computer-assisted Magnetic Resonance Imaging Male Oxygen/blood Psychomotor Performance/physiology Smoking/psychology Smoking/psychology Smoking Cessation/psychology Smoking Cessation/psychology Young Adult

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High-sensitivity C-reactive protein is associated with hippocampus volume in nondementia patients with type 2 diabetes mellitus

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METABOLISM-CLINICAL AND EXPERIMENTAL 2011年第4期60卷 460-466页

作者： Anan, Futoshi Masaki, Takayuki Shimomura, Tsuyoshi Fujiki, Minoru Umeno, Yoshikazu Eshima, Nobuoki Saikawa, Tetsunori Yoshimatsu, Hironobu Oita Red Cross Hosp Dept Cardiol Oita 8700033 Japan Oita Univ Dept Internal Med 1 Sch Med Oita 87011 Japan Oita Univ Dept Neurosurg Sch Med Oita 87011 Japan Oita Red Cross Hosp Dept Endocrinol Oita 8700033 Japan Oita Univ Dept Biostat Sch Med Oita 87011 Japan Oita Univ Dept Lab Med Sch Med Oita 87011 Japan

The elevated level of high-sensitivity C-reactive protein (HSCRP) is associated with cognitive dysfunction, for which changes in the hippocampus plausibly play a pivotal role. We tested the hypothesis that an elevated level of HSCRP correlates with hippocampus volume and insulin resistance in nondementia patients with type 2 diabetes mellitus. Subjects included 45 nondementia patients with type 2 diabetes mellitus, who were divided into 2 groups: high-HSCRP group (age, 65 +/- 6 years [mean +/- SD];n = 17) and normal-HSCRP group (65 +/- 7 years, n = 28). Hippocampus volume has been quantitated with computer-assisted analysis using a magnetic resonance imaging voxel-based specific regional analysis system developed for the study of Alzheimer disease.(VSRAD), which yields a z score as the end point for assessment of hippocampal volume. The z score was higher in the high-HSCRP group than in the nonnal-HSCRP group (P < .0001). The fasting plasma glucose (P < .05) and insulin concentrations (P < .0001) and the homeostasis model assessment (HOMA) index (P < .0001) were higher in the high-HSCRP group than in the nonnal-HSCRP group. Multiple regression analysis showed that HSCRP levels were independently predicted by z score and HOMA index. Our results indicate that the elevated level of HSCRP in Japanese nondementia patients with type 2 diabetes mellitus is characterized by increased hippocampus volume and insulin resistance, and that the z score and HOMA index are independent predictors of HSCRP. (C) 2011 Elsevier Inc. All rights reserved.

关键词： Aged Body Mass Index Brain/pathology Cognition/physiology C-Reactive Protein/metabolism Diabetes Mellitus, Type 2/blood Diabetes Mellitus, Type 2/pathology Diabetes Mellitus, Type 2/psychology Female Heart Rate/physiology Hippocampus/pathology Humans Hypertension/complications Hypertension/physiopathology image processing, computer-assisted Insulin/blood Insulin/blood Insulin Resistance/physiology Lipid Metabolism/physiology Magnetic Resonance Imaging Male Middle Aged Neuropsychological Tests Regression Analysis

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Microscopic diffusion tensor atlas of the mouse brain

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NEUROimage 2011年第3期56卷 1235-1243页

作者： Jiang, Yi Johnson, G. Allan Duke Univ Med Ctr Ctr Vivo Microscopy Durham NC 27710 USA

Eight diffusion tensor imaging (DTI) datasets of normal adult C57BL/6J mouse brains were acquired with an isotropic Nyquist limited resolution of 43 mu m (voxel volume -80 pl). Each specimen was scanned with a b0 image and 6 diffusion-weighted images. T1- and T2*-weighted data were acquired with each specimen to aid nonlinear registration of the data to a common reference space (called "Waxholm Space"). We identified 80 different discrete landmarks in Waxholm Space to provide the gold standard for measuring the registration quality. The accuracy of the registration was established by measuring displacement of the 80 landmarks in each registered brain from the same landmarks in the reference brain. The accuracy was better than 130 gm for 95% of the landmarks (overall landmark displacement is 65 +/- 40 mu m, n = 640). Mean and coefficient of variation atlases of DTI indices were generated with potential application for both voxel-based and region of interest-based analysis. To examine consistency of DTI data among individual subjects in this study and difference in diffusion indices between separate brain structures within each subject, averaged values of DTI indices (axial diffusivity. radial diffusivity, fractional anisotropy, and angular deviation of the primary eigenvector) were computed in 9 white matter structures in each brain. The variation of the DTI indices across the population was very small. e.g., similar to 5% for axial diffusivity for each white matter structure, enabling confident differentiation of differences in these structures within each subject. ANOVA tests indicated that the current protocol is able to provide consistent DTI data of individual brains (p>0.25), and distinguish difference of diffusion indices between white matter structures (p<0.001). Power analysis was also performed to provide an estimate of the number of specimens required to detect a 10% change of the DTI indices in each white matter structure. The data provide a critical addi

关键词： Analysis of Variance Animals Atlases as Topic Brain/anatomy & histology Databases, Factual Diffusion Tensor Imaging/methods Diffusion Tensor Imaging/methods image processing, computer-assisted Informatics Internet Male Mice Mice, Inbred C57BL/anatomy & histology

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Uncovering Camouflage: Amygdala Activation Predicts Long-Term Memory of Induced Perceptual Insight

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NEURON 2011年第5期69卷 1002-1014页

作者： Ludmer, Rachel Dudai, Yadin Rubin, Nava New York Univ Ctr Neural Sci New York NY 10003 USA Weizmann Inst Sci Dept Neurobiol IL-76100 Rehovot Israel

What brain mechanisms underlie learning of new knowledge from single events? We studied encoding in long-term memory of a unique type of one-shot experience, induced perceptual insight. While undergoing an fMRI brain scan, participants viewed degraded images of real-world pictures where the underlying objects were hard to recognize ("camouflage"), followed by brief exposures to the original images ("solution"), which led to induced insight ("Aha!"). A week later, the participants' memory was tested;a solution image was classified as "remembered" if detailed perceptual knowledge was elicited from the camouflage image alone. During encoding, subsequently remembered images were associated with higher activity in midlevel visual cortex and medial frontal cortex, but most pronouncedly, in the amygdala, whose activity could be used to predict which solutions will remain in long-term memory. Our findings extend the known roles of amygdala in memory to include promotion of long-term memory of the sudden reorganization of internal representations.

关键词： Adult Amygdala/physiology Analysis of Variance Brain Mapping Brain Mapping Cerebral Cortex/physiology Female Humans image processing, computer-assisted Magnetic Resonance Imaging Male Memory, Long-Term/physiology Photic Stimulation Recognition (Psychology)/physiology Visual Perception/physiology

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Segmentation of the thalamus in MRI based on T1 and T2

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NEUROimage 2011年第3期56卷 939-950页

作者： Traynor, Catherine R. Barker, Gareth J. Crum, William R. Williams, Steve C. R. Richardson, Mark P. Kings Coll London Inst Psychiat Dept Clin Neurosci London England Kings Coll London Inst Psychiat Dept Neuroimaging London England

Reliable identification of thalamic nuclei is required to improve positioning of electrodes in Deep Brain Stimulation (DBS). and to allow the role of individual thalamic nuclei in health and disease to be fully investigated. In this work, a previously proposed method for identifying sub-regions within the thalamus based on differences in their T1 and 12 values is explored in detail. The effect on the segmentation of T1 and 12 dependence weighted against priors for spatial position and extent was investigated. When T1 and 12 dependence was highly weighted, good distinction between identified regions was obtained in T1/T2 feature-space, but no contiguous anatomically distinct regions were identified within the thalamus. Incorporating spatial priors was necessary to ensure anatomically distinct regions were defined. Optimal values for segmentation parameters were obtained by assessing performance on a 'synthetic thalamus'. Using these optimum input parameters, within- and between-subjects reproducibility was assessed. Good reproducibility was obtained when six regions were specified to be identified in the thalamus. The six regions identified were similar in the majority of the normal subject group. However, intriguingly these regions were different from those obtained in the same subjects using a well-known connectivity-based segmentation technique. This method shows promise to identify intrathalamic structures on the basis of T1 and 12 signal. A comprehensive characterisation of thalamic nuclei may require a fully multi-modal approach. (C) 2011 Elsevier Inc. All rights reserved.

关键词： Algorithms Brain Mapping/methods Brain Mapping/methods Cluster Analysis computer Simulation Data Interpretation, Statistical Diffusion Tensor Imaging Diffusion Tensor Imaging Functional Laterality/physiology Humans image processing, computer-assisted Magnetic Resonance Imaging/methods Male Models, Statistical Reproducibility of Results Thalamic Nuclei/anatomy & histology Thalamus/anatomy & histology Young Adult

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Effective connectivity analysis demonstrates involvement of premotor cortex during speech perception

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NEUROimage 2011年第3期54卷 2437-2445页

作者： Osnes, Berge Hugdahl, Kenneth Specht, Karsten Univ Bergen Dept Biol & Med Psychol N-5009 Bergen Norway Haukeland Hosp Div Psychiat N-5021 Bergen Norway Haukeland Hosp Bergen Mental Hlth Ctr N-5021 Bergen Norway Haukeland Hosp Dept Clin Engn N-5021 Bergen Norway

Several reports of premotor cortex involvement in speech perception have been put forward. Still, the functional role of premotor cortex is under debate. In order to investigate the functional role of premotor cortex, we presented parametrically varied speech stimuli in both a behavioral and functional magnetic resonance imaging (fMRI) study. White noise was transformed over seven distinct steps into a speech sound and presented to the participants in a randomized order. As control condition served the same transformation from white noise into a music instrument sound. The fMRI data were modelled with Dynamic Causal Modeling (DCM) where the effective connectivity between Heschl's gyrus, planum temporale, superior temporal sulcus and premotor cortex were tested. The fMRI results revealed a graded increase in activation in the left superior temporal sulcus. Premotor cortex activity was only present at an intermediate step when the speech sounds became identifiable but were still distorted but was not present when the speech sounds were clearly perceivable. A Bayesian model selection procedure favored a model that contained significant interconnections between Heschl's gyrus, planum temporal, and superior temporal sulcus when processing speech sounds. In addition, bidirectional connections between premotor cortex and superior temporal sulcus and from planum temporale to premotor cortex were significant. processing non-speech sounds initiated no significant connections to premotor cortex. Since the highest level of motor activity was observed only when processing identifiable sounds with incomplete phonological information, it is concluded that premotor cortex is not generally necessary for speech perception but may facilitate interpreting a sound as speech when the acoustic input is sparse. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Acoustic Stimulation Adult Bayes Theorem Brain Mapping Brain Mapping Data Interpretation, Statistical Humans image processing, computer-assisted Linear Models Magnetic Resonance Imaging Male Models, Neurological Motor Cortex/physiology Music Neural Pathways/physiology Noise Noise Speech Perception/physiology Temporal Lobe/physiopathology

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