Journals

The US National Institutes of Health (NIH) have funded an increasing number of grants from young investigators with merit scores below the payline. This policy is critical for retaining and encouraging our future scientific base.

Learning to see in stereo

Donald MitchellDennis LeviDaphne Bavelier

Any kind of mother in a storm

Robert Sapolsky During early development, rats show the unlikely behavior of becoming attracted to the very stimulus that they should avoid. A new study shows that this occurs as a result of a complex interplay of glucocorticoid secretion and dopaminergic tone in the amygdala.

How to button a bouton with ?2?s

Stephan J SigristAndrew J R Plested The ?2?-3 auxiliary subunit of voltage-dependent calcium channels promotes the formation of synaptic boutons in Drosophila neuromuscular junction independently of its role in channel localization.

Optimizing brain processing

Alexander Thiele Cholinergic neurons in the basal forebrain enable alert and attending brain states. A study now shows how basal forebrain activity increases coding abilities of cortical neurons and at what stages these changes occur.

Formation and maintenance of Alzheimer's disease ?-amyloid plaques in the absence of microglia

Stefan A GrathwohlRoland E K�linTristan BolmontStefan ProkopGeorg WinkelmannStephan A KaeserJ�rg OdenthalRebecca RaddeTherese EldhSam GandyAdriano AguzziMatthias StaufenbielPaul M MathewsHartwig WolburgFrank L HeppnerMathias Jucker Contrary to previous findings, this study finds that ablation of microglia, the resident macrophages of the brain, does not affect amyloid plaque or neuritic pathology in two mouse models of Alzheimer's disease.

Unmasking the tonic-aversive state in neuropathic pain

Tamara KingLouis Vera-PortocarreroTannia GutierrezTodd W VanderahGregory DussorJosephine LaiHoward L FieldsFrank Porreca Tonic pain, a chief clinical problem, is difficult to study in rodent models that measure threshold changes of evoked reactions to acutely applied stimuli. These authors used conditioned place preference to assess tonic pain in rats and measure the efficacy of agents that relieve it.

Transitions in infant learning are modulated by dopamine in the amygdala

Gordon A BarrStephanie MoriceauKiseko ShionoyaKyle MuznyPuhong GaoShaoning WangRegina M Sullivan The instinctual attachment of young animals to their mothers is crucial for survival. Demonstrating the overriding importance of attachment, very young rat pups learn to prefer an odor coupled to electrical shock if the mother is present. This paper shows that low amygdalar dopamine signaling in very young pups is essential for their paradoxical response to odor/shock conditioning.

Training induces changes in white-matter architecture

Jan ScholzMiriam C KleinTimothy E J BehrensHeidi Johansen-Berg Although previous work has shown that extensive training in the complex visuo-motor skills involved in juggling results in adult gray-matter changes, it is unclear whether such practice can produce similar changes in adult white matter. This paper now uses diffusion tensor imaging to demonstrate structural white-matter changes when adults practice juggling.

Sip1 regulates sequential fate decisions by feedback signaling from postmitotic neurons to progenitors

Eve SeuntjensAnjana NityanandamAmaya MiquelajaureguiJoke DebruynAgata StryjewskaSandra GoebbelsKlaus-Armin NaveDanny HuylebroeckVictor Tarabykin Smad-interacting protein 1 (Sip1) is a transcriptional repressor that acts in the TGF-? signaling pathway. This study finds that Sip1 is involved in a feedback signaling mechanism in which newly generated postmitotic cells in neocortical layers instruct progenitor cells for proper cell-fate switch and proliferation.

Lhx2 specifies regional fate in Emx1 lineage of telencephalic progenitors generating cerebral cortex

Shen-Ju ChouCarlos G Perez-GarciaTodd T KrollDennis D M O'Leary The authors show that the LIM homeodomain transcription factor Lhx2 is responsible for the fate decision of cortical progenitors to generate neocortex or olfactory cortex. Conditional deletion of Lhx2 in telencephalic progenitors refated them to generate three-layer cortex resembling olfactory cortex, rather than lateral neocortex.

GSK-3 is a master regulator of neural progenitor homeostasis

Woo-Yang KimXinshuo WangYaohong WuBradley W DobleSatish PatelJames R WoodgettWilliam D Snider The authors report the conditional deletion of the alpha and beta forms of glycogen synthase kinase 3 (GSK-3) in mouse neural progenitors. This deletion is associated with dysregulations in ?-catenin, Sonic Hedgehog, Notch and fibroblast growth factor signaling pathways and leads to markedly increased proliferation of neural progenitors.

The oligodendrocyte-specific G protein?coupled receptor GPR17 is a cell-intrinsic timer of myelination

Ying ChenHeng WuShuzong WangHisami KoitoJianrong LiFeng YeJenny HoangSabine S EscobarAlexander GowHeather A ArnettBruce D TrappNitin J KarandikarJenny HsiehQ Richard Lu Here, Chen et al. describe the role of the G protein?coupled receptor GPR17 in oligodendrocytes and show that it acts as a negative regulator of oligodendrocyte maturation and myelination.

Mst3b, an Ste20-like kinase, regulates axon regeneration in mature CNS and PNS pathways

Barbara LorberMariko L HoweLarry I BenowitzNina Irwin This study shows that the kinase Mst3b is required cell-autonomously for axon regeneration of both retinal ganglion cells and peripheral sensory neurons in vitro and in vivo.

Presynaptic ?2?-3 is required for synaptic morphogenesis independent of its Ca2+-channel functions

Peri T KurshanAsli OztanThomas L Schwarz The main function of the ?2?-3 calcium channel subunit is thought to be facilitation of the pore-forming subunit delivery to presynaptic terminals. Kurshan et al. now show that this subunit has other, independent synaptogenic functions and that it is important for shaping the architecture of the synapse.

Functional consequences of animal-to-animal variation in circuit parameters

Jean-Marc GoaillardAdam L TaylorDavid J SchulzEve Marder The authors found considerable preparation-to-preparation variability in the strength of two identified synapses, the amplitude of a modulator-evoked current and the expression of six ion channel genes in the pyloric circuit of the crab stomatogastric ganglion. These parameters correlated with circuit performance. Circuits produced similar outputs because of compensatory and coordinated changes among the parameters.

PDF-modulated visual inputs and cryptochrome define diurnal behavior in Drosophila

Paola CusumanoAndr� KlarsfeldElisabeth Ch�lotMarie PicotBenjamin RichierFran�ois Rouyer Using endogenous circadian oscillators, Drosophila can anticipate diurnal light on/off transition and behave accordingly. Here, the authors show that the fly evening oscillator circuit can synchronize to light cycle through the visual system and the molecular components of morning oscillator.

CREB regulates excitability and the allocation of memory to subsets of neurons in the amygdala

Yu ZhouJaejoon WonMikael Guzman KarlssonMiou ZhouThomas RogersonJayaprakash BalajiRachael NevePanayiota PoiraziAlcino J Silva Silva et al. show that CREB modulates allocation of fear memory to specific cells in the lateral amygdala. Reversibly inactivating a subset of CREB-expressing neurons disrupted memory for tone conditioning. Neurons with higher CREB levels were more excitable than their neighbors and showed larger synaptic efficacy changes following tone conditioning.

Basal forebrain activation enhances cortical coding of natural scenes

Michael GoardYang Dan The nucleus basalis is thought to regulate arousal and attention via release of acetylcholine in the cortex. Here the authors report that nucleus basalis stimulation in rats results in a decorrelation between visual cortical neurons as a result of activation of cortical muscarinic receptors and an increase in the reliability of responses to natural scenes as a result of more distributed changes along the visual pathway.

Behavioral choice by presynaptic inhibition of tactile sensory terminals

Quentin GaudryWilliam B Kristan A feeding leech ignores incoming stimuli that would normally cause an avoidance response. This study found that synaptic transmission from mechanosensory neurons to postsynaptic partners was reduced in feeding leeches. This presynaptic depression by feeding could be mimicked by serotonin and was antagonized by a blocker of an unusual serotonin-gated chloride channel.

Frontal eye field neurons signal changes in decision criteria

Vincent P FerreraMarianna YanikeCarlos Cassanello Monkeys were trained to switch rapidly between two category boundaries when classifying the speed of a moving dot pattern. Neurons in the frontal eye field changed their activity when the boundary changed and a subset of these neurons were used to classify the stimuli nearly as accurately as the monkeys' behavioral performance.

Persistent neural activity in the human frontal cortex when maintaining space that is off the map

Kyeong-Jin TarkClayton E Curtis Activity in the frontal eye fields (FEF) is important for visuospatial processing and is thought to code information in retinal coordinates. This fMRI study finds FEF activity even for auditory locations behind the head, suggesting that extra-retinal space is also coded in this area.

Neural activity predicts attitude change in cognitive dissonance

Vincent van VeenMarie K KrugJonathan W SchoolerCameron S Carter When our actions conflict with our prior attitudes, we often change our attitudes to be more consistent with our actions, a phenomenon that is known as cognitive dissonance. Here the authors report that activity during cognitive dissonance in the dorsal anterior cingulate cortex and anterior insula predicts subsequent attitude changes.

ScienceDirect Publication: NeuroImage

Structural and cognitive deficits in remitting and non-remitting recurrent depression: A voxel-based morphometric study

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 19 November 2009Cheng-Ta, Li , Ching-Po, Lin , Kun-Hsien, Chou , I-Yun, Chen , Jen-Chuen, Hsieh , ...Remission is the optimal outcome for major depressive disorder (MDD), but many patients do not improve appreciably despite treatment with medication. Treatment-resistant patients may experience deterioration in cognitive functions. Research has reported structural abnormalities in certain brain areas that may contribute to a poor clinical response. We hypothesize that there will be structural differences between patients able to achieve remission and those responding poorly to antidepressants. In the first voxel-based morphometric (VBM) study comparing remitting with non-remitting MDD, we investigated gray matter volume (GMV) differences between depressives to determine which structural abnormalities existed, and correlated these with diminished cognitive functioning....

Structural and cognitive deficits in remitting and non-remitting recurrent depression: A voxel-based morphometric study

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 19 November 2009Cheng-Ta, Li , Ching-Po, Lin , Kun-Hsien, Chou , I-Yun, Chen , Jen-Chuen, Hsieh , ...Remission is the optimal outcome for major depressive disorder (MDD), but many patients do not improve appreciably despite treatment with medication. Treatment-resistant patients may experience deterioration in cognitive functions. Research has reported structural abnormalities in certain brain areas that may contribute to a poor clinical response. We hypothesize that there will be structural differences between patients able to achieve remission and those responding poorly to antidepressants. In the first voxel-based morphometric (VBM) study comparing remitting with non-remitting MDD, we investigated gray matter volume (GMV) differences between depressives to determine which structural abnormalities existed, and correlated these with diminished cognitive functioning....

Imaging Brain Fatigue from Sustained Mental Workload: An ASL Perfusion Study of the Time-On-Task Effect

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Julian, Lim , Wen-chau, Wu , Jiongjiong, Wang , John A., Detre , David F., Dinges , ...During sustained periods of a taxing cognitive workload, humans typically display time-on-task (TOT) effects, in which performance gets steadily worse over the period of task engagement. Arterial spin labeling (ASL) perfusion functional magnetic resonance imaging (fMRI) was used in this study to investigate the neural correlates of TOT effects in a group of 15 subjects as they performed a 20-minute continuous psychomotor vigilance test (PVT). Subjects displayed significant TOT effects, as seen in progressively slower reaction times and significantly increased mental fatigue ratings after the task. Perfusion data showed that the PVT activates a right lateralized fronto-parietal attentional network in...

Enhancing cognitive control through neurofeedback: A role of gamma-band activity in managing episodic retrieval

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009André W., Keizer , Roland S., Verment , Bernhard, HommelNeural synchronization has been proposed to be the underlying mechanism for exchanging and integrating anatomically distributed information and has been associated with a myriad of cognitive domains, including visual feature binding, top-down control, and long-term memory. Moreover, it seems that separate frequency bands have different functions in these cognitive processes. Here we studied whether neurofeedback training designed either to increase local gamma band activity (GBA; 36-44 Hz), or local beta band activity (BBA; 12-20 Hz), would have an impact on performance of behavioral tasks measuring short-term and long-term episodic binding. Our results show that GBA-enhancing neurofeedback training increased occipital GBA...

BDNF Gene Polymorphism (Val66Met) Predicts Amygdala and Anterior Hippocampus Responses to Emotional Faces in Anxious and Depressed Adolescents

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Jennifer Y.F., Lau , David, Goldman , Beata, Buzas , Colin, Hodgkinson , Ellen, Leibenluft , ...A polymorphism of the human Brain Derived Neurotrophic Factor (BDNF) gene that produces a valine-to-methionine substitution at codon 66 (Val66Met), is linked to adult anxiety and mood disorders, possibly through effects on brain circuitry function. Associations between BDNF gene variants and brain activity have not been explored in anxious and depressed adolescents. The current study investigated the association between BDNF genotype and amygdala-hippocampal responses to emotional stimuli in adolescents with anxiety disorders and/or major depressive disorder (MDD) and in healthy adolescents. Twenty-seven unmedicated patients with acutely-impairing current anxiety disorders and/or MDD and 31 healthy adolescents, matched on age, gender and...

11C-methionine uptake correlates with tumor cell density rather than with microvessel density in glioma: a stereotactic image-histology comparison

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Yoshiko, Okita , Manabu, Kinoshita , Tetsu, Goto , Naoki, Kagawa , Haruhiko, Kishima , ...11C-methionine positron emission tomography (11C-methionine PET) provides accurate detection of brain tumors. Several reports have analyzed the correlation between uptake of 11C-methionine and Ki-67 index or microvessel density non-stereotactically and suggested that 11C-methionine uptake reflects both proliferation potential and angiogenic capability in gliomas. As gliomas possess heterogeneous histological architecture, non-stereotactic comparison of the histology and 11C-methionine PET image may not be accurate. In the present study, the correlation between 11C-methionine uptake and cell or microvessel density was analyzed using histological specimens obtained by stereotactic biopsy, and an exact local comparison of 11C-methionine PET image and histological specimens was conducted. The...

Amygdala Volume in Depressed Patients with Bipolar Disorder Assessed Using High Resolution 3T MRI: The Impact of Medication

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Jonathan, Savitz , Allison C., Nugent , Wendy, Bogers , Alice, Liu , Rebecca, Sills , ...MRI-based reports of both abnormally increased and decreased amygdala volume in bipolar disorder (BD) have surfaced in the literature. Two major methodological weaknesses characterizing extant studies are treatment with medication and inaccurate segmentation of the amygdala due to limitations in spatial and tissue contrast resolution. Here, we acquired high-resolution images (voxel size=0.55x0.55x0.60mm) using a GE 3T MRI scanner, and a pulse sequence optimized for tissue contrast resolution. The amygdala was manually segmented by one rater blind to diagnosis, using coronal images. Eighteen unmedicated (mean medication-free period 11+10 months) BD subjects were age and gender matched with 18 healthy controls, and...

Multi-graphical analysis of dynamic PET

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Yun, Zhou , Weiguo, Ye , James R., Bra?i? , Dean F., WongIn quantitative dynamic PET studies, graphical analysis methods including the Gjedde-Patlak plot, the Logan plot, and the relative equilibrium-based graphical plot (RE plot) (Zhou et al., 2009b) are based on the theory of a compartmental model with assumptions on tissue tracer kinetics. If those assumptions are violated, then the resulting estimates may be biased. In this study, a multi-graphical analysis method was developed to characterize the non-relative equilibrium effects on the estimates of total distribution volume (DVT) from the RE plot. A novel bi-graphical analysis method using the RE plot with the Gjedde-Patlak plot (RE-GP plots) was proposed to estimate...

Diffusion Tensor ImagingSegments the Human Amygdala In Vivo

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Eugenia, Solano-Castiella , Alfred, Anwander , Gabriele, Lohmann , Marcel, Weiss , Carol, Docherty , ...The amygdala plays an important role in emotion, learning, and memory. It would be highly advantageous to understand more precisely its internal structure and connectivity, for individual human subjects in vivo. Earlier cytoarchitectural research in post-mortem human and animal brains has revealed multiple subdivisions and connectivity patterns, probably related to different functions. With standard magnetic resonance imaging (MRI) techniques, however, the amygdala appears as an undifferentiated area of grey matter. Using high quality diffusion tensor imaging (DTI) at 3 Tesla, we show diffusion anisotropy in this grey matter area. Such data allowed us to subdivide the amygdala for the first...

Discriminative Analysis of Resting-state Functional Connectivity Patterns of Schizophrenia Using Low Dimensional Embedding of fMRI

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 18 November 2009Hui, Shen , Lubin, Wang , Yadong, Liu , Dewen, HuRecently, a functional disconnectivity hypothesis of schizophrenia has been proposed for the physiological explanation of behavioral syndromes of this complex mental disorder. In this paper, we aim at further examining whether syndromes of schizophrenia could be decoded by some special spatio-temporal patterns of resting-state functional connectivity. We designed a data-driven classifier based on machine learning to extract highly discriminative functional connectivity features and to discriminate schizophrenic patients from healthy controls. The proposed classifier consisted of two separate steps. First, we used feature selection based on a correlation coefficient method to extract highly discriminative regions and construct the optimal feature set...

Phonological processing in post-lingual deafness and cochlear implant outcome

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 18 November 2009D.S., Lazard , H.J., Lee , M., Gaebler , C.A., Kell , E., Truy , ...Cochlear implants work well, yet the outcome is not fully accounted by the data routinely available to the clinician, and remains unpredictable. A more in-depth understanding of the neural mechanisms that determine the clinical recovery after cochlear implantation is warranted, as they may provide the background for an accurate individual prognosis. In this study in post-lingually deaf adults, we show that while clinical data offer only prognosis trends, fMRI data can prospectively distinguish good from poor implant performers. We show that those deaf cochlear implant (CI) candidates who will become good performers rely on a dorsal phonological route when performing...

Social Cognition and the Anterior Temporal Lobes

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 18 November 2009Lars A., Ross , Ingrid R., OlsonTwo distinct literatures have emerged on the functionality of the anterior temporal lobes (ATL): in one field, the ATLs are conceived of as a repository for semantic or conceptual knowledge. In another field, the ATLs are thought to play some undetermined role in social-emotional functions such as Theory of Mind. Here we attempted to reconcile these distinct functions by assessing whether social semantic processing can explain ATL activation in other social cognitive tasks. Social semantic functions refer to knowledge about social concepts and rules. In a first experiment we tested the idea that social semantic representations can account for activations...

Imaging Brain Fatigue from Sustained Mental Workload: An ASL Perfusion Study of the Time-On-Task Effect

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Julian, Lim , Wen-chau, Wu , Jiongjiong, Wang , John A., Detre , David F., Dinges , ...During sustained periods of a taxing cognitive workload, humans typically display time-on-task (TOT) effects, in which performance gets steadily worse over the period of task engagement. Arterial spin labeling (ASL) perfusion functional magnetic resonance imaging (fMRI) was used in this study to investigate the neural correlates of TOT effects in a group of 15 subjects as they performed a 20-minute continuous psychomotor vigilance test (PVT). Subjects displayed significant TOT effects, as seen in progressively slower reaction times and significantly increased mental fatigue ratings after the task. Perfusion data showed that the PVT activates a right lateralized fronto-parietal attentional network in...

Enhancing cognitive control through neurofeedback: A role of gamma-band activity in managing episodic retrieval

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009André W., Keizer , Roland S., Verment , Bernhard, HommelNeural synchronization has been proposed to be the underlying mechanism for exchanging and integrating anatomically distributed information and has been associated with a myriad of cognitive domains, including visual feature binding, top-down control, and long-term memory. Moreover, it seems that separate frequency bands have different functions in these cognitive processes. Here we studied whether neurofeedback training designed either to increase local gamma band activity (GBA; 36-44 Hz), or local beta band activity (BBA; 12-20 Hz), would have an impact on performance of behavioral tasks measuring short-term and long-term episodic binding. Our results show that GBA-enhancing neurofeedback training increased occipital GBA...

BDNF Gene Polymorphism (Val66Met) Predicts Amygdala and Anterior Hippocampus Responses to Emotional Faces in Anxious and Depressed Adolescents

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Jennifer Y.F., Lau , David, Goldman , Beata, Buzas , Colin, Hodgkinson , Ellen, Leibenluft , ...A polymorphism of the human Brain Derived Neurotrophic Factor (BDNF) gene that produces a valine-to-methionine substitution at codon 66 (Val66Met), is linked to adult anxiety and mood disorders, possibly through effects on brain circuitry function. Associations between BDNF gene variants and brain activity have not been explored in anxious and depressed adolescents. The current study investigated the association between BDNF genotype and amygdala-hippocampal responses to emotional stimuli in adolescents with anxiety disorders and/or major depressive disorder (MDD) and in healthy adolescents. Twenty-seven unmedicated patients with acutely-impairing current anxiety disorders and/or MDD and 31 healthy adolescents, matched on age, gender and...

11C-methionine uptake correlates with tumor cell density rather than with microvessel density in glioma: a stereotactic image-histology comparison

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Yoshiko, Okita , Manabu, Kinoshita , Tetsu, Goto , Naoki, Kagawa , Haruhiko, Kishima , ...11C-methionine positron emission tomography (11C-methionine PET) provides accurate detection of brain tumors. Several reports have analyzed the correlation between uptake of 11C-methionine and Ki-67 index or microvessel density non-stereotactically and suggested that 11C-methionine uptake reflects both proliferation potential and angiogenic capability in gliomas. As gliomas possess heterogeneous histological architecture, non-stereotactic comparison of the histology and 11C-methionine PET image may not be accurate. In the present study, the correlation between 11C-methionine uptake and cell or microvessel density was analyzed using histological specimens obtained by stereotactic biopsy, and an exact local comparison of 11C-methionine PET image and histological specimens was conducted. The...

Amygdala Volume in Depressed Patients with Bipolar Disorder Assessed Using High Resolution 3T MRI: The Impact of Medication

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Jonathan, Savitz , Allison C., Nugent , Wendy, Bogers , Alice, Liu , Rebecca, Sills , ...MRI-based reports of both abnormally increased and decreased amygdala volume in bipolar disorder (BD) have surfaced in the literature. Two major methodological weaknesses characterizing extant studies are treatment with medication and inaccurate segmentation of the amygdala due to limitations in spatial and tissue contrast resolution. Here, we acquired high-resolution images (voxel size=0.55x0.55x0.60mm) using a GE 3T MRI scanner, and a pulse sequence optimized for tissue contrast resolution. The amygdala was manually segmented by one rater blind to diagnosis, using coronal images. Eighteen unmedicated (mean medication-free period 11+10 months) BD subjects were age and gender matched with 18 healthy controls, and...

Multi-graphical analysis of dynamic PET

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Yun, Zhou , Weiguo, Ye , James R., Bra?i? , Dean F., WongIn quantitative dynamic PET studies, graphical analysis methods including the Gjedde-Patlak plot, the Logan plot, and the relative equilibrium-based graphical plot (RE plot) (Zhou et al., 2009b) are based on the theory of a compartmental model with assumptions on tissue tracer kinetics. If those assumptions are violated, then the resulting estimates may be biased. In this study, a multi-graphical analysis method was developed to characterize the non-relative equilibrium effects on the estimates of total distribution volume (DVT) from the RE plot. A novel bi-graphical analysis method using the RE plot with the Gjedde-Patlak plot (RE-GP plots) was proposed to estimate...

Diffusion Tensor ImagingSegments the Human Amygdala In Vivo

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 17 November 2009Eugenia, Solano-Castiella , Alfred, Anwander , Gabriele, Lohmann , Marcel, Weiss , Carol, Docherty , ...The amygdala plays an important role in emotion, learning, and memory. It would be highly advantageous to understand more precisely its internal structure and connectivity, for individual human subjects in vivo. Earlier cytoarchitectural research in post-mortem human and animal brains has revealed multiple subdivisions and connectivity patterns, probably related to different functions. With standard magnetic resonance imaging (MRI) techniques, however, the amygdala appears as an undifferentiated area of grey matter. Using high quality diffusion tensor imaging (DTI) at 3 Tesla, we show diffusion anisotropy in this grey matter area. Such data allowed us to subdivide the amygdala for the first...

A Multiple-plane Approach to Measure the Structural Properties of Functionally Active Regions in the Human Cortex

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009Xin, Wang , Sarah N., Garfinkel , Anthony P., King , Mike, Angstadt , Michael J., Dennis , ...Advanced magnetic resonance imaging (MRI) techniques provide the means of studying both the structural and the functional properties of various brain regions, allowing us to address the relationship between the structural changes in human brain regions and the activity of these regions. However, analytical approaches combining functional (fMRI) and structural (sMRI) information are still far from optimal. In order to improve the accuracy of measurement of structural properties in active regions, the current study tested a new analytical approach that repeated a surface-based analysis at multiple planes crossing different depths of cortex. Twelve subjects underwent a fear conditioning study. During...

Executive control function, brain activation and white matter hyperintensities in older adults

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009Vijay K., Venkatraman , Howard, Aizenstein , Jack, Guralnik , Anne B., Newman , Nancy W., Glynn , ...Context: Older adults responding to executive control function (ECF) tasks show greater brain activation on functional MRI (fMRI). It is not clear whether greater fMRI activation indicates a strategy to compensate for underlying brain structural abnormalities while maintaining higher performance.Objective: To identify the patterns of fMRI activation in relationship with ECF performance and with brain structural abnormalities.Design: Cross-sectional analysis. Main variables of interest: fMRI activation, accuracy while performing an ECF task (Digit Symbol Substitution Test), volume of white matter hyperintensities and of total brain atrophy.Setting: Cohort of community-dwelling older adults.Participants: Data were obtained on 25 older adults (20 women, 81...

Distributed subordinate specificity for bodies, faces, and buildings in human ventral visual cortex

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009Hans P., Op de Beeck , Marijke, Brants , Annelies, Baeck , Johan, WagemansPrevious studies have revealed regions in human visual cortex with a strong preference for faces, headless bodies, and buildings. We investigated whether the pattern of activity in these category-selective regions is related to more subordinate distinctions among objects. Our experiments included two types of faces (elderly faces and baby faces), body parts (hands and torsos), and buildings (rural buildings and skyscrapers). Multi-voxel pattern analyses revealed very clear differences in the activation pattern between hands and torsos, and smaller but significant differences in the activation pattern between the two face conditions and between the two building conditions. The subordinate specificity was...

Cortico-spinal Synchronization Reflects Changes in Performance when Learning a Complex Bimanual Task

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009S., Houweling , B.W., van Dijk , P.J., Beek , A., DaffertshoferMotor performance is accompanied by neural activity in various cortical and sub-cortical areas. This intricate network has to be delicately orchestrated. We analyzed the role of beta synchronization in motor learning using magneto-encephalography combined with electromyography. Cortico-spinal synchronization in the beta band was found to be of particular importance in establishing bimanual movement patterns in the context of a 3:2 polyrhythmic (isometric) force production task. Its dynamics correlated highly with the learning of this complex bimanual motor skill. We submit that the cortical dynamics entrains the spinal motor system by which cortico-spinal beta synchrony serves higher-level motor control functions as...

A Multiple-plane Approach to Measure the Structural Properties of Functionally Active Regions in the Human Cortex

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009Xin, Wang , Sarah N., Garfinkel , Anthony P., King , Mike, Angstadt , Michael J., Dennis , ...Advanced magnetic resonance imaging (MRI) techniques provide the means of studying both the structural and the functional properties of various brain regions, allowing us to address the relationship between the structural changes in human brain regions and the activity of these regions. However, analytical approaches combining functional (fMRI) and structural (sMRI) information are still far from optimal. In order to improve the accuracy of measurement of structural properties in active regions, the current study tested a new analytical approach that repeated a surface-based analysis at multiple planes crossing different depths of cortex. Twelve subjects underwent a fear conditioning study. During...

Executive control function, brain activation and white matter hyperintensities in older adults

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009Vijay K., Venkatraman , Howard, Aizenstein , Jack, Guralnik , Anne B., Newman , Nancy W., Glynn , ...Context: Older adults responding to executive control function (ECF) tasks show greater brain activation on functional MRI (fMRI). It is not clear whether greater fMRI activation indicates a strategy to compensate for underlying brain structural abnormalities while maintaining higher performance.Objective: To identify the patterns of fMRI activation in relationship with ECF performance and with brain structural abnormalities.Design: Cross-sectional analysis. Main variables of interest: fMRI activation, accuracy while performing an ECF task (Digit Symbol Substitution Test), volume of white matter hyperintensities and of total brain atrophy.Setting: Cohort of community-dwelling older adults.Participants: Data were obtained on 25 older adults (20 women, 81...

Distributed subordinate specificity for bodies, faces, and buildings in human ventral visual cortex

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009Hans P., Op de Beeck , Marijke, Brants , Annelies, Baeck , Johan, WagemansPrevious studies have revealed regions in human visual cortex with a strong preference for faces, headless bodies, and buildings. We investigated whether the pattern of activity in these category-selective regions is related to more subordinate distinctions among objects. Our experiments included two types of faces (elderly faces and baby faces), body parts (hands and torsos), and buildings (rural buildings and skyscrapers). Multi-voxel pattern analyses revealed very clear differences in the activation pattern between hands and torsos, and smaller but significant differences in the activation pattern between the two face conditions and between the two building conditions. The subordinate specificity was...

Cortico-spinal Synchronization Reflects Changes in Performance when Learning a Complex Bimanual Task

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 14 November 2009S., Houweling , B.W., van Dijk , P.J., Beek , A., DaffertshoferMotor performance is accompanied by neural activity in various cortical and sub-cortical areas. This intricate network has to be delicately orchestrated. We analyzed the role of beta synchronization in motor learning using magneto-encephalography combined with electromyography. Cortico-spinal synchronization in the beta band was found to be of particular importance in establishing bimanual movement patterns in the context of a 3:2 polyrhythmic (isometric) force production task. Its dynamics correlated highly with the learning of this complex bimanual motor skill. We submit that the cortical dynamics entrains the spinal motor system by which cortico-spinal beta synchrony serves higher-level motor control functions as...

K-space reconstruction of magnetic resonance inverse imaging (K-InI) of human visuomotor systems

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 13 November 2009Fa-Hsuan, Lin , Thomas, Witzel , Wei-Tang, Chang , Wen-Kai, Tsai , Yen-Hsiang, Wang , ...Using simultaneous measurements from multiple channels of a radio-frequency coil array, magnetic resonance inverse imaging (InI) can achieve ultra-fast dynamic functional imaging of the human with whole-brain coverage and a good spatial resolution. Mathematically, the InI reconstruction is a generalization of parallel MRI (pMRI), which includes image space and k-space reconstructions. Because of the auto-calibration technique, the pMRI k-space reconstruction offers more robust and adaptive reconstructions compared to the image space algorithm. Here we present the k-space InI (K-InI) reconstructions to reconstruct the highly accelerated BOLD-contrast fMRI data of the human brain to achieve 100 ms temporal resolution. Simulations show...

Dissociation of neural networks for anticipation and consumption of monetary and social rewards

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009Lena, Rademacher , Sören, Krach , Gregor, Kohls , Arda, Irmak , Gerhard, Gründer , ...Human behaviour is generally guided by the anticipation of potential outcomes that are considered to be rewarding. Reward processing can thus be dissected into a phase of reward anticipation and a phase of reward consumption. A number of brain structures have been suggested to be involved in reward processing. However, it is unclear whether anticipation and consumption are mediated by the same or different neural networks. We examined the neural basis of these processes using functional magnetic resonance imaging (fMRI) in an incentive delay task offering either money or social approval. In both conditions participants (N=28) were given a cue...

Impact of Scanner Hardware and Imaging Protocol on Image Quality and Compartment Volume Precision in the ADNI Cohort

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009Frithjof, Kruggel , Jessica, Turner , L. Tugan, MuftulerMorphometry of brain structures based on magnetic resonance imaging (MRI) data has become an important tool in neurobiology. Recent multicenter studies in neurodegenerative diseases raised the issue of the precision of volumetric measures, and their dependence on the scanner properties and imaging protocol. A large dataset consisting of 1073 MRI examinations in 843 subjects, acquired on 90 scanners at 58 sites, is analyzed here. A comprehensive set of image quality and content measures is used to describe the influence of the scanner hardware and imaging protocol on the variability of morphometric measures. Scanners equipped with array coils show a remarkable...

When less is more: TPJ and Default Network Deactivation During Encoding Predicts Working Memory Performance

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009Alan, Anticevic , Grega, Repovs , Gordon L., Shulman , Deanna M., BarchPrevious work has shown that temporo-parietal junction (TPJ), part of a ventral attention network for stimulus-driven reorienting, deactivates during effortful cognitive engagement, along with the default mode network (DMN). TPJ deactivation has been reported both during working memory (WM) and rapid visual search, ostensibly to prevent reorienting to irrelevant objects. We tested whether the magnitude of this deactivation during WM encoding is predictive of subsequent WM performance. Using slow event-related fMRI and a delayed WM task in which distracter stimuli were presented during the maintenance phase, we found that greater TPJ and DMN deactivation during the encoding phase predicted better...

Combining functional and anatomical connectivity reveals brain networks for auditory language comprehension

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009Dorothee, Saur , Björn, Schelter , Susanne, Schnell , David, Kratochvil , Hanna, Küpper , ...Cognitive functions are organized in distributed, overlapping and interacting brain networks. Investigation of those large-scale brain networks is a major task in neuroimaging research.Here, we introduce a novel combination of functional and anatomical connectivity to study the network topology subserving a cognitive function of interest. (i) In a given network, direct interactions between network nodes are identified by analyzing functional MRI time series with the multivariate method of directed partial correlation (dPC). This method provides important improvements over shortcomings that are typical for ordinary (partial) correlation techniques. (ii) For directly interacting pairs of nodes, a region-to-region probabilistic fiber tracking on...

Additive effect of NRG1 and DISC1 genes on lateral ventricle enlargement in first episode schizophrenia

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009I., Mata , R., Perez-Iglesias , R., Roiz-Santiañez , D., Tordesillas-Gutierrez , A., Gonzalez-Mandly , ...Neuregulin 1 (NRG1) and Disrupted-in-schizophrenia (DISC1) genes, which are candidate genes for schizophrenia, are implicated in brain development. We have previously reported an association between the T allele of the rs6994992 SNP within NRG1 gene and lateral ventricle (LV) enlargement in first-episode schizophrenia patients. Moreover, transgenic mice with mutant DISC1 have also been reported as showing LV enlargement. In this study, we examined the possible interactive effects of NRG1 and DISC1 on brain volumes in a sample of first-episode schizophrenia patients. Ninety-one patients experiencing their first episode of schizophrenia underwent genotyping of three SNPs within DISC1 and structural brain MRI....

Investigating hemodynamic response variability at the group level using basis functions

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009Jason, Steffener , Matthias, Tabert , Aaron, Reuben , Yaakov, SternIntroduced is a general framework for performing group level analyses of fMRI data using any basis set of two functions (i.e. the canonical hemodynamic response function and its first derivative) to model the hemodynamic response to neural activity. The approach allows for flexible implementation of physiologically based restrictions on the results. Information from both basis functions is used at the group level and the limitations avoid physiologically ambiguous or implausible results. This allows for investigation of specific BOLD activity such as hemodynamic responses peaking within a specified temporal range (i.e. 4 to 5 seconds). The general nature of the presented...

Ten Simple Rules for Dynamic Causal Modelling

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 12 November 2009K.E., Stephan , W.D., Penny , R.J., Moran , H.E.M., den Ouden , J., Daunizeau , ...Dynamic causal modelling (DCM) is a generic Bayesian framework for inferring hidden neuronal states from measurements of brain activity. It provides posterior estimates of neurobiologically interpretable quantities such as the effective strength of synaptic connections among neuronal populations and their context-dependent modulation. DCM is increasingly used in the analysis of a wide range of neuroimaging and electrophysiological data. Given the relative complexity of DCM, compared to conventional analysis techniques, a good knowledge of its theoretical foundations is needed to avoid pitfalls in its application and interpretation of results. By providing good practice recommendations for DCM, in the form of ten...

Cognitive Control of Drug Craving Inhibits Brain Reward Regions in Cocaine Abusers

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 11 November 2009Nora D., Volkow , Joanna S., Fowler , Gene-Jack, Wang , Frank, Telang , Jean, Logan , ...

Sub-cortical and brainstem sites associated with chemo-stimulated increases in ventilation in humans

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 11 November 2009Leanne C., McKay , Hugo D., Critchley , Kevin, Murphy , Richard S.J., Frackowiak , Douglas R., CorfieldWe investigated the neural basis for spontaneous chemostimulated increases in ventilation in awake, healthy humans. Blood oxygen level dependent (BOLD) functional MRI was performed in nine healthy subjects using T2? weighted echo planar imaging. Brain volumes (52 transverse slices, cortex to high spinal cord) were acquired every 3.9 s. The 30 minute paradigm consisted of six, five?minute cycles, each cycle comprising 45 seconds of hypoxic-isocapnia, 45 seconds of isooxic-hypercapnia and 45 seconds of hypoxic-hypercapnia, with 55 seconds of non?stimulatory hyperoxic-isocapnia (control) separating each stimulus period. Ventilation was significantly (p < 0.001) increased during hypoxic-isocapnia, isooxic-hypercapnia and hypoxic-hypercapnia (17.0, 13.8, 24.9...

Quantitative Analysis of the Hippocampus Using Images Obtained from 7.0T MRI

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 10 November 2009Zang-Hee, Cho , Jae-Yong, Han , Seok-Il, Hwang , Dae-shik, Kim , Kyoung-Nam, Kim , ...In-vivo volumetric measurements of hippocampus have proven to be highly informative for studying various neurological diseases such as Alzheimer's disease. The usefulness of volumetric imaging, however, has been limited due to the poor image resolutions obtained by currently available MRI images. In this study, a new result of volumetric image measurement of the hippocampus using 7.0T MRI images of high contrast and resolution is described. To verify the usefulness of the proposed method, its reliability and sensitivity were examined and compared with existing imaging techniques such as 1.5T or 3.0T MRI imaging. The results of our study with 7.0T MRI...

Changes in fMRI Magnitude Data and Phase Data Observed in Block-Design and Event-Related Tasks

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 10 November 2009Sunil Kumar, Arja , Zhaomei, Feng , Zikuan, Chen , Arvind, Caprihan , Kent A., Kiehl , ...Functional magnetic resonance imaging (fMRI) data is acquired as a complex image pair including magnitude and phase information. The vast majority of fMRI experiments do not attempt to take advantage of the time varying phase information. The phase of the MRI signal is related to the local magnetic field changes, suggesting it may contain useful information about the source of hemodynamic activity. Analysis of phase data acquired from different fMRI experiments has shown the presence of activity in response to various stimuli. However, there have been no studies that have examined phase data in a larger group of subjects for...

Identifying the brain?s most globally connected regions

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 10 November 2009Michael W., Cole , Sudhir, Pathak , Walter, SchneiderRecent advances in brain connectivity methods have made it possible to identify hubs ? the brain?s most globally connected regions. Such regions are essential for coordinating brain functions due to their connectivity with numerous regions with a variety of specializations. Current structural and functional connectivity methods generally agree that default mode network (DMN) regions have among the highest global brain connectivity (GBC). We developed two novel statistical approaches using resting state functional connectivity MRI ? weighted and unweighted GBC (wGBC and uGBC) ? to test the hypothesis that the highest global connectivity also occurs in the cognitive control network (CCN),...

Differential temporo-parietal cortical networks that support relational and item-based recency judgments

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 10 November 2009Hiroko M., Kimura , Satoshi, Hirose , Akira, Kunimatsu , Junichi, Chikazoe , Koji, Jimura , ...There is a growing interest in the parietal cortical role for episodic memory retrieval. Previous functional magnetic resonance imaging (fMRI) studies of recency judgments, judgments of the relative temporal order of two studied items, have highlighted the involvement of the lateral prefrontal and medial temporal regions. However, the parietal cortical contribution to recency judgments has rarely been highlighted. To examine the parietal involvement, in this study, we conducted a re-analysis to increase the statistical power using three data sets (N = 73) from our previous fMRI studies of recency judgments. Recency judgments can be achieved by at least two mechanisms,...

The development of performance-monitoring function in the posterior medial frontal cortex

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 10 November 2009Kate Dimond, Fitzgerald , Suzanne C., Perkins , Mike, Angstadt , Timothy, Johnson , Emily R., Stern , ...Background: Despite its critical role in performance-monitoring, the development of posterior medial prefrontal cortex (pMFC) in goal-directed behaviors remains poorly understood. Performance monitoring depends on distinct, but related functions that may differentially activate the pMFC, such as monitoring response conflict and detecting errors. Developmental differences in conflict-and error-related activations, coupled with age-related changes in behavioral performance, may confound attempts to map the maturation of pMFC functions. To characterize the development of pMFC-based performance monitoring functions, we segregated interference and error-processing, while statistically controlling for performance. Methods: Twenty-one adults and 23 youth performed an event-related version of the Multi-Source Interference Task...

In-vivo Visualization of Reactive Gliosis Using Manganese-enhanced Magnetic Resonance Imaging

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 10 November 2009Yuko, Kawai , Ichio, Aoki , Masahiro, Umeda , Toshihiro, Higuchi , Jeff, Kershaw , ...Reactive astrogliosis occurs after diverse central nervous system (CNS) insults. While astrogliosis provides protection against inflammation, it is also obstructive in the progress of neuranagenesis after CNS insults. Thus, a method that enables in-vivo visualization and tissue characterization of gliosis would be invaluable for studies of CNS insults and corresponding treatments. Manganese has proven to be a useful MRI contrast agent that enters cells via Ca2+ channels and has been applied to manganese-enhanced MRI (MEMRI) for neuronal functional mapping. This study investigated whether MEMRI can detect astrogliosis after focal ischemia in-vivo. Rats were divided into groups according to the number...

Intraoperative dynamic susceptibility contrast MRI (iDSC-MRI) is as reliable as preoperatively acquired perfusion mapping

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 6 November 2009Stephan, Ulmer , Gesa, Hartwigsen , Christian, Riedel , Olav, Jansen , H. Maximilian, Mehdorn , ...DSC-MRI was applied intraoperatively during human brain tumor removal. Immediately after complete tumor resection was presumed, MRI including a dynamic susceptibility contrast T2?-weighted EPI sequence was performed in 30 patients while the skull was still open using a flexible two-channel coil system at an intraoperative 1.5-Tesla MR scanner. Maps of relative regional blood flow (rCBF), blood volume (rCBV), and mean transit time (MTT) were calculated, and ratios of these maps were compared to preoperatively acquired DSC-MRI data. The extent of the resection was compared with the postoperative MRI performed 24 h after the operation. In 8 of these patients residual...

Multivariate Tensor-based Morphometry on Surfaces: Application to Mapping Ventricular Abnormalities in HIV/AIDS

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 6 November 2009Yalin, Wang , Jie, Zhang , Boris, Gutman , Tony F., Chan , James T., Becker , ...Here we developed a new method, called multivariate tensor-based surface morphometry (TBM), and applied it to study lateral ventricular surface dif- ferences associated with HIV/AIDS. Using concepts from differential geome- try and the theory of differential forms, we created mathematical structures known as holomorphic one-forms, to obtain an efficient and accurate confor- mal parameterization of the lateral ventricular surfaces in the brain. The new meshing approach also provides a natural way to register anatomical surfaces across subjects, and improves on prior methods as it handles sur- faces that branch and join at complex 3D junctions. To analyze anatomical differences, we...

Probabilistic tractography of the optic radiations ? an automated method and anatomical validation

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 6 November 2009P.L., Clatworthy , G.B., Williams , J., Acosta-Cabronero , S.P., Jones , S.G., Harding , ...Accurately tracing the optic radiations in living humans has important implications for studying the relationship between tract structure or integrity and visual function, in health and disease. Probabilistic tractography is an established method for tracing white matter tracts in humans. Prior studies have used this method to trace the optic radiations, but operator-dependent factors, particularly variability in seed voxel placement and choice of connectivity threshold to select between tract and non-tract voxels, remain potential causes of significant variability. Methods using prior information to modify tract images risk introducing error by underestimating individual variability, particularly in subjects with abnormal anatomy. Finally,...

Unbiased ROI selection in neuroimaging studies of individual differences

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 6 November 2009Roberto, VivianiIndividual differences studies are those that investigate the interaction between a subject level covariate, such as sex, age, or performance, and the effect of an experimental task. Commonly, a brain region is selected on the basis of the task effect, and the signal in this region correlated with individual covariates. It is shown here that, provided that data are identically and independently distributed between subjects, the selection of the region on the basis of the task effect is unbiased in two cases: when selection is based on a one-sample t test of the task effect, or when the subject level...

Local White Matter Geometry from Diffusion Tensor Gradients

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 5 November 2009Peter, Savadjiev , Gordon L., Kindlmann , Sylvain, Bouix , Martha E., Shenton , Carl-Fredrik, WestinWe introduce a mathematical framework for computing geometrical properties of white matter fibres directly from diffusion tensor fields. The key idea is to isolate the portion of the gradient of the tensor field corresponding to local variation in tensor orientation, and to project it onto a coordinate frame of tensor eigenvectors. The resulting eigenframe-centered representation then makes it possible to define scalar indices (or measures) that describe the local white matter geometry directly from the diffusion tensor field and its gradient, without requiring prior tractography. We derive new scalar indices of (1) fibre dispersion and (2) fibre curving, and we...

Identifying True Cortical Interactions in MEG using the Nulling Beamformer

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 5 November 2009Hua Brian, Hui , Dimitrios, Pantazis , Steven L., Bressler , Richard M., LeahyModeling functional brain interaction networks using non-invasive EEG and MEG data is more challenging than using intracranial recording data. This is because most interaction measures are not robust to the cross-talk (interference) between cortical regions, which may arise due to the limited spatial resolution of EEG/MEG inverse procedures. In this paper we describe a modi_ed beamforming approach to accurately measure cortical interactions from EEG/MEG data, designed to suppress cross-talk between cortical regions. We estimate interaction measures from the output of the modi_ed beamformer and test for statistical signi_cance using permutation tests. Since the underlying neuronal sources and their interactions are...

Reliable Intrinsic Connectivity Networks: Test-Retest Evaluation Using ICA and Dual Regression Approach

Publication year: 2009Source: NeuroImage, In Press, Accepted Manuscript, Available online 5 November 2009X.N., Zuo , C., Kelly , J.S., Adelstein , D.F., Klein , F.X., Castellanos , ...Functional connectivity analyses of resting-state fMRI data are rapidly emerging as highly efficient and powerful tools for in vivo mapping of functional networks in the brain, referred to as intrinsic connectivity networks (ICNs). Despite a burgeoning literature, researchers continue to struggle with the challenge of defining computationally efficient and reliable approaches for identifying and characterizing ICNs. Independent component analysis (ICA) has emerged as a powerful tool for exploring ICNs in both healthy and clinical populations. In particular, temporal concatenation group ICA (TCGICA) coupled with a back-reconstruction step produces participant-level RSFC maps for each group-level component. The present work systematically evaluated...

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