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Working memory component processes: Isolating BOLD signal changes

NEUROimage 2010年第2期49卷 1933-1941页

作者： Motes, Michael A. Rypma, Bart Univ Texas Dallas Ctr BrainHlth Dallas TX 75235 USA Univ Texas Dallas Sch Behav & Brain Sci Dallas TX 75235 USA Univ Texas SW Med Ctr Dept Psychiat Dallas TX USA

The chronology of the component processes subserving working memory (WM) and hemodynamic response lags has hindered the use of fMRI for exploring neural substrates of WM. In the present study, however, participants completed full trials that involved encoding two or six letters, maintaining the memory set over a delay, and then deciding whether a probe was in the memory set or not. Additionally, they completed encode-only, encode-and-maintain, and encode-and-decide partial trials intermixed with the full trials. The inclusion of partial trials allowed for the isolation of BOLD signal changes to the different trial periods. The results showed that only lateral and medial prefrontal cortex regions differentially responded to the 2- and 6-letter memory sets over the trial periods, showing greater activation to 6-letter sets during the encode and maintain trial periods. Thus, the data showed the differential involvement of PFC in the encoding and maintenance of supra- and sub-capacity memory sets and show the efficacy of using fMRI partial trial methods to study WM component processes. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Adult Brain/blood supply Brain/physiology Brain Mapping Brain Mapping Cerebrovascular Circulation Female Hemodynamics Humans image processing, computer-assisted Magnetic Resonance Imaging/methods Male Memory, Short-Term/physiology Neuropsychological Tests Oxygen/blood Prefrontal Cortex/blood supply Prefrontal Cortex/physiology Time Factors Young Adult

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Topographic Representation of the Human Body in the Occipitotemporal Cortex

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NEURON 2010年第3期68卷 586-600页

作者： Orlov, Tanya Makin, Tamar R. Zohary, Ehud Hebrew Univ Jerusalem Inst Life Sci Dept Neurobiol IL-91904 Jerusalem Israel Hebrew Univ Jerusalem Interdisciplinary Ctr Neural Computat IL-91904 Jerusalem Israel Univ Oxford Dept Clin Neurol Ctr Funct Magnet Resonance Imaging Brain Oxford OX3 9DU England

Large-scale topographic representations of the body have long been established in the somatosensory and motor cortices. Using functional imaging, we identified a topographically organized body part map within the occipitotemporal cortex (OTC), with distinct clusters of voxels showing clear preference for different visually presented body parts. This representation was consistent both across hemispheres and participants. Using converging methods, the preference for specific body parts was demonstrated to be robust and did not merely reflect shape differences between the categories. Finally, execution of (unseen) movements with different body parts resulted in a limited topographic representation of the limbs and trunk, which partially overlapped with the visual body part map. This motor-driven activation in the OTC could not be explained solely by visual or motor imagery of the body parts. This suggests that visual and motor-related information converge within the OTC in a body part specific manner.

关键词： Adult Body image Brain Mapping Brain Mapping Female Form Perception/physiology Humans image processing, computer-assisted Magnetic Resonance Imaging Male Motor Cortex/physiology Movement/physiology Neural Pathways/physiology Occipital Lobe/physiology Oxygen/blood Psychomotor Performance/physiology Temporal Lobe/physiology Visual Cortex/physiology Visual Perception/physiology

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Brain pathology in first-episode psychosis: Magnetization transfer imaging provides additional information to MRI measurements of volume loss

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NEUROimage 2010年第1期49卷 185-192页

作者： Price, Gary Cercignani, Mara Chu, Elvina M. Barnes, Thomas R. E. Barker, Gareth J. Joyce, Eileen M. Ron, Maria A. UCL Inst Neurol London WC1N 3BG England Univ London Imperial Coll Sci Technol & Med Fac Med London England Kings Coll London Inst Psychiat Dept Clin Neurosci Ctr Neuroimaging Sci London WC2R 2LS England IRCCS Fdn Santa Lucia Neuroimaging Lab Rome Italy

Background: Loss of brain volume in first-episode psychosis can be detected using conventional magnetic resonance imaging (MRI), but subtle changes - not leading to reduction in volume - that may contribute to clinical and cognitive abnormalities, may go undetected. Magnetization transfer imaging (MTI), a technique more sensitive to subtle neuropathological changes than conventional MRI, could yield important information on the extent and nature of structural abnormalities. Methods: Forty-eight patients (33 males) from a population-based sample with first-episode psychosis (41 with schizophrenia and 7 with schizoaffective psychosis) and 47 healthy volunteers (27 males) were studied. Differences in magnetization transfer ratio (MTR) and white and grey matter volumes between groups were investigated. Results: In patients, MTR was reduced in right entorhinal cortex, fusiform, dentate and superior frontal gyri and in left superior frontal and inferior/rostral cingulate gyri. Grey matter volume was reduced in right insula, frontal operculum and middle and superior temporal gyri and in left middle temporal gyrus. Grey matter volume increases were seen in patients in the superior frontal gyrus. White matter volume loss was found adjacent to grey matter loss. In patients MTR was lower in all areas of volumetric differences between groups suggesting that both changes may be related. Similar findings were observed when patients with schizoaffective psychosis were removed from the analysis. The correlations between clinical and MRI parameters did not survive correction for Multiple comparisons. Conclusions: MTI frontal and temporal abnormalities suggesting neuroaxonal and myelin changes were more extensive in our patients than those detected with conventional MRI. Our findings also suggest that there is regional variation in the severity of structural brain abnormalities. (c) 2009 Elsevier Inc. All rights reserved.

关键词： Adolescent Adult Antipsychotic Agents/therapeutic use Brain/pathology Brain Mapping Brain Mapping Cerebral Cortex/pathology Confidence Intervals Female Humans image processing, computer-assisted Imaging, Three-Dimensional Magnetic Resonance Imaging Male Middle Aged Psychotic Disorders/drug therapy Psychotic Disorders/pathology Schizophrenia/pathology Young Adult

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Neural Responses to Ingroup and Outgroup Members' Suffering Predict Individual Differences in Costly Helping

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NEURON 2010年第1期68卷 149-160页

作者： Hein, Grit Silani, Giorgia Preuschoff, Kerstin Batson, C. Daniel Singer, Tania Univ Zurich Inst Empir Res Econ Lab Social & Neural Syst Res CH-8006 Zurich Switzerland Univ Kansas Dept Psychol Lawrence KS 66045 USA Max Planck Inst Human Cognit & Brain Sci Dept Social Neurosci D-04103 Leipzig Germany

Little is known about the neurobiological mechanisms underlying prosocial decisions and how they are modulated by social factors such as perceived group membership. The present study investigates the neural processes preceding the willingness to engage in costly helping toward ingroup and outgroup members. Soccer fans witnessed a fan of their favorite team (ingroup member) or of a rival team (outgroup member) experience pain. They were subsequently able to choose to help the other by enduring physical pain themselves to reduce the other's pain. Helping the ingroup member was best predicted by anterior insula activation when seeing him suffer and by associated self-reports of empathic concern. In contrast, not helping the outgroup member was best predicted by nucleus accumbens activation and the degree of negative evaluation of the other. We conclude that empathy-related insula activation can motivate costly helping, whereas an antagonistic signal in nucleus accumbens reduces the propensity to help.

关键词： Adult Brain/blood supply Brain/physiopathology Brain Mapping Brain Mapping Empathy/physiology Group Processes Helping Behavior Humans image processing, computer-assisted Individuality Interpersonal Relations Magnetic Resonance Imaging/methods Male Oxygen/blood Pain/psychology Predictive Value of Tests Questionnaires Social Identification Stress, Psychological/pathology Stress, Psychological/physiopathology Stress, Psychological/psychology Young Adult

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Dual echo EPI - The method of choice for fMRI in the presence of magnetic field inhomogeneities?

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NEUROimage 2010年第1期49卷 316-326页

作者： Schwarzbauer, Christian Mildner, Toralf Heinke, Wolfgang Brett, Matthew Deichmann, Ralf MRC Cognit & Brain Sci Unit Cambridge CB2 7EF England Univ Cambridge Dept Psychiat Cambridge England Max Planck Inst Human Cognit & Brain Sci Leipzig Germany Univ Leipzig Dept Anaesthesiol & Intens Care Therapy Leipzig Germany Univ Calif Berkeley Helen Wills Neurosci Inst Berkeley CA 94720 USA Goethe Univ Frankfurt Brain Imaging Ctr Frankfurt Germany

FMRI studies of the orbitofrontal cortex or the inferior temporal lobes are often compromised by susceptibility artefacts, which may result in signal reduction or loss in gradient echo (GE) EPI. Spin echo (SE) EPI is considerably more robust against susceptibility-related signal loss, but its intrinsic sensitivity to changes in the blood oxygenation level dependent (BOLD) contrast is generally lower. In this study, we performed a direct comparison of GE and SE fMRI using a single-shot dual echo EPI acquisition scheme. Transient hypercapnia, induced by breathing Carbogen (5% CO(2), 95% O(2)), was used as a global physiological stimulus to alter the BOLD contrast. In regions affected by magnetic field inhomogeneities, SE EPI provided significantly higher BOLD sensitivity than GE EPI. Such regions included the orbitofrontal cortex, temporal pole, anterior inferior temporal cortex, as well as parts of the lateral inferior temporal cortex and the lateral cerebellum. Dual echo fMRI benefits from the robustness of SE EPI in these critical regions while utilising the generally higher sensitivity of GE EPI in normal regions. It therefore provides an attractive solution for fMRI studies that require optimum sensitivity in both normal and critical brain regions. Furthermore, a general method is proposed to combine the GE and SE data into a single hybrid data set that provides optimum sensitivity in the whole brain. This method can be applied to any experimental design that can be expressed in terms of a generalised linear model. The feasibility of this approach is demonstrated both theoretically and experimentally. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Artifacts Brain/anatomy & histology Brain Mapping Brain Mapping Data Interpretation, Statistical Databases, Factual Echo-Planar Imaging/methods Electromagnetic Fields Electromagnetic Fields Female Humans image processing, computer-assisted Magnetic Resonance Imaging/methods Male Young Adult

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Sources of group differences in functional connectivity: An investigation applied to autism spectrum disorder

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NEUROimage 2010年第1期49卷 401-414页

作者： Jones, Tyler B. Bandettini, Peter A. Kenworthy, Lauren Case, Laura K. Milleville, Shawn C. Martin, Alex Birn, Rasmus M. NIMH Lab Brain & Cognit NIH Bethesda MD 20892 USA Childrens Natl Med Ctr Ctr Autism Spectrum Disorders Washington DC 20010 USA

An increasing number of fMRI studies are using the correlation of low-frequency fluctuations between brain regions, believed to reflect synchronized variations in neuronal activity, to infer "functional connectivity". In studies of autism spectrum disorder (ASD), decreases in this measure of connectivity have been found by focusing on the response to task modulation, by using only the rest periods, or by analyzing purely resting-state data. This difference in connectivity, however, could result from a number of different mechanisms differences in noise, task-related fluctuations, task performance, or spontaneous neuronal activity. In this Study, we investigate the difference in functional connectivity between adolescents with high-functioning ASD and typically developing control subjects by examining the residual fluctuations occurring on top of the fMRI response to an overt verbal fluency task. We find decreased correlations of these residuals (a decreased "connectivity") in ASD subjects. Furthermore, we find that this decrease was not due to task-related effects, block-to-block variations in task performance, or increased noise, and the difference was greatest when primarily rest periods are considered. These findings suggest that the estimate of disrupted functional connectivity in ASD is likely driven by differences in task-unrelated neuronal fluctuations. (C) Published by Elsevier Inc.

关键词： Adolescent Aging/physiology Algorithms Child Child Development Disorders, Pervasive/pathology Child Development Disorders, Pervasive/psychology Executive Function/physiology Humans image processing, computer-assisted Language Magnetic Resonance Imaging Male Neural Pathways/pathology Neuropsychological Tests Psychiatric Status Rating Scales Regression Analysis Social Behavior Verbal Behavior

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Dissociable responses to punishment in distinct striatal regions during reversal learning

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NEUROimage 2010年第4期51卷 1459-1467页

作者： Robinson, Oliver J. Frank, Michael J. Sahakian, Barbara J. Cools, Roshan Univ Cambridge Addenbrookes Hosp Dept Psychiat Cambridge CB2 2QQ England Univ Cambridge Addenbrookes Hosp Behav & Clin Neurosci Inst Cambridge CB2 2QQ England NIMH Sect Neuroimaging Mood & Anxiety Disorders NIH Bethesda MD 20892 USA Brown Univ Dept Cognit & Linguist Sci Dept Psychol Brown Inst Brain SciDept Psychiat & Human Behav Providence RI 02912 USA Radboud Univ Nijmegen Donders Inst Brain Cognit & Behav Ctr Cognit Neuroimaging Dept PsychiatMed Ctr NL-6525 ED Nijmegen Netherlands

Adaptive behavior depends on the ability to flexibly alter our choices in response to changes in reward and punishment contingencies. One brain region frequently implicated in such behavior is the striatum. However, this region is functionally diverse and there are a number of apparent inconsistencies across previous studies. For instance, how can significant BOLD responses in the ventral striatum during punishment-based reversal learning be reconciled with the frequently demonstrated role of the ventral striatum in reward processing? Here we attempt to address this question by separately examining BOLD responses during reversal learning driven by reward and during reversal learning driven by punishment. We demonstrate simultaneous valence-specific and valence-nonspecific signals in the striatum, with the posterior dorsal striatum responding only to unexpected reward, and the anterior ventral striatum responding to both unexpected punishment as well as unexpected reward. These data help to reconcile conflicting findings from previous studies by showing that distinct regions of the striatum exhibit dissociable responses to punishment during reversal learning. Published by Elsevier Inc.

关键词： Adult Electrophysiology Female Humans image processing, computer-assisted Linear Models Magnetic Resonance Imaging Male Neostriatum/physiology Oxygen/blood Photic Stimulation Psychomotor Performance/physiology Punishment/psychology Reaction Time/physiology Reversal Learning/physiology Reward Young Adult

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fMRI adaptation dissociates syntactic complexity dimensions

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NEUROimage 2010年第4期51卷 1285-1293页

作者： Santi, Andrea Grodzinsky, Yosef McGill Univ Dept Linguist Montreal PQ H3A 1A7 Canada Max Planck Inst Human Cognit & Brain Sci Dept Neuropsychol D-04103 Leipzig Germany

The current fMRI adaptation study sought to elucidate the dimensions of syntactic complexity and their underlying neural substrates. For the first time with fMRI, we investigated repetition suppression (i.e., fMRI adaptation) for two orthogonal dimensions of sentence complexity: embedding position (right-branching vs. center-embedding) and movement type (subject vs. object). Two novel results were obtained: First, we found syntactic adaptation in Broca's area and second, this adaptation was structured. Anterior Broca's area (BA 45) selectively adapted to movement type, while posterior Broca's area (BA 44) demonstrated adaptation to both movement type and embedding position (as did left posterior superior temporal gyrus and right inferior precentral sulcus). The functional distinction within Broca's area is critical not only to an understanding of the functional neuroanatomy of language, but also to theoretical accounts of syntactic complexity, demonstrating its multi-dimensional nature. These results implicate that during syntactic comprehension, a large network of areas is engaged, but that only anterior Broca's area is selective to syntactic movement. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Acoustic Stimulation Adaptation, Physiological/physiology Adult Behavior/physiology Cerebral Cortex/anatomy & histology Cerebral Cortex/physiology Female Frontal Lobe/anatomy & histology Frontal Lobe/physiology Humans image processing, computer-assisted Language Magnetic Resonance Imaging/methods Male Middle Aged Movement Oxygen/blood Photic Stimulation Psycholinguistics/methods Reading Young Adult

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A new graphic plot analysis for determination of neuroreceptor binding in positron emission tomography studies

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NEUROimage 2010年第1期49卷 578-586页

作者： Ito, Hiroshi Yokoi, Takashi Ikoma, Yoko Shidahara, Miho Seki, Chie Naganawa, Mika Takahashi, Hidehiko Takano, Harumasa Kimura, Yuichi Ichise, Masanori Suhara, Tetsuya Natl Inst Radiol Sci Mol Imaging Ctr Mol Neuroimaging Grp Clin Neuroimaging TeamInage Ku Chiba 2638555 Japan Bioimaging Lab Inc Kyoto Japan Natl Inst Radiol Sci Mol Imaging Ctr Biophys Grp Image Anal Team Chiba 2638555 Japan Columbia Univ Coll Phys Dept Radiol Kreitchman PET Ctr New York NY USA

In positron emission tomography (PET) studies with radioligands for neuroreceptors, tracer kinetics have been described by the standard two-tissue compartment model that includes the compartments of nondisplaceable binding and specific binding to receptors. In the present Study, we have developed a new graphic plot analysis to determine the total distribution volume (V(T)) and nondisplaceable distribution volume (V(ND)) independently, and therefore the binding potential (BP(ND)). In this plot, Y(t) is the ratio of brain tissue activity to time-integrated arterial input function, and X(t) is the ratio of time-integrated brain tissue activity to time-integrated arterial input function. The x-intercept of linear regression of the plots for early phase represents V(ND), and the x-intercept of linear regression of the plots for delayed phase after the equilibrium time represents V(T). BP(ND) can be calculated by BP(ND) = V(T)/V(ND) - 1. Dynamic PET scanning with measurement of arterial input function was performed on six healthy men after intravenous rapid bolus injection of [(11)C]FLB457. The plot yielded a curve in regions with specific binding while it yielded a straight line through all plot data in regions with no specific binding. V(ND), V(T), and BP(ND) values calculated by the present method were in good agreement with those by conventional non-linear least-squares fitting procedure. This method can be used to distinguish graphically whether the radioligand binding includes specific binding or not. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Brain/physiology Brain/radionuclide imaging Brain Chemistry/physiology computer Simulation Humans image processing, computer-assisted Kinetics Least-Squares Analysis Ligands Linear Models Male Positron-Emission Tomography Radiopharmaceuticals/diagnostic use Radiopharmaceuticals/diagnostic use Receptors, Dopamine D2/metabolism Sensory Receptor Cells/metabolism Sensory Receptor Cells/radionuclide imaging Young Adult

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Identifying population differences in whole-brain structural networks: A machine learning approach

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NEUROimage 2010年第3期50卷 910-919页

作者： Robinson, Emma C. Hammers, Alexander Ericsson, Anders Edwards, A. David Rueckert, Daniel Univ London Imperial Coll Sci Technol & Med Dept Comp London SW7 2BZ England Univ London Imperial Coll Sci Technol & Med Fac Med MRC Ctr Clin Sci London W12 0NN England Univ London Imperial Coll Sci Technol & Med Fac Med Div Neurosci London W12 0NN England Univ London Imperial Coll Sci Technol & Med Div Clin Sci London W12 0NN England CERMEP Neurodis Fdn F-69003 Lyon France

Models of whole-brain connectivity are valuable for understanding neurological function, development and disease. This paper presents a machine learning based approach to classify subjects according to their approximated structural connectivity pattern!;and to identify features which represent the key differences between groups. Brain networks are extracted from diffusion magnetic resonance images obtained by a clinically viable acquisition protocol. Connections are tracked between 83 regions of interest automatically extracted by label propagation from multiple brain atlases followed by classifier fusion. Tracts between these regions are propagated by probabilistic tracking, and mean anisotropy measurements along these connections provide the feature vectors for combined principal component analysis and maximum uncertainty linear discriminant analysis, The approach is tested on two populations with different age distributions: 20-30 and 60-90 years. We show that subjects can be classified successfully (with 87.46% accuracy) and that the features extracted from the discriminant analysis agree with Current consensus on the neurological impact of ageing. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Adult Aged Aged, 80 and over Aging Algorithms Anisotropy Artificial Intelligence Automation Brain/physiology Databases, Factual Diffusion Magnetic Resonance Imaging Discriminant Analysis Humans image processing, computer-assisted Middle Aged Neural Networks (computer) Neural Pathways/physiology Young Adult

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