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Koji Ikezoe, Mahya Amano, Shinji Nishimoto, Ichiro Fujita
In vivo calcium (Ca2+) imaging using two-photon microscopy allows activity to be monitored simultaneously from hundreds of individual neurons within a local population. While this allows us to gain important insights into how cortical neurons represent sensory information, factors such as photo-bleaching of the Ca2+ indicator limit imaging duration (and thus the numbers of stimuli that can be tested), which in turn hampers the full characterization of neuronal response properties. Here, we demonstrate that using an encoding model combined with presentation of natural movies results in detailed characterization of receptive field (RF) properties despite the relatively short time for data collection...
January 10, 2018: NeuroImage
Kabilar Gunalan, Bryan Howell, Cameron C McIntyre
Medical imaging has played a major role in defining the general anatomical targets for deep brain stimulation (DBS) therapies. However, specifics on the underlying brain circuitry that is directly modulated by DBS electric fields remain relatively undefined. Detailed biophysical modeling of DBS provides an approach to quantify the theoretical responses to stimulation at the cellular level, and has established a key role for axonal activation in the therapeutic mechanisms of DBS. Estimates of DBS-induced axonal activation can then be coupled with advances in defining the structural connectome of the human brain to provide insight into the modulated brain circuitry and possible correlations with clinical outcomes...
January 10, 2018: NeuroImage
Theodosia Vallianatou, Nicole Strittmatter, Anna Nilsson, Mohammadreza Shariatgorji, Gregory Hamm, Marcela Pereira, Patrik Källback, Per Svenningsson, Maria Karlgren, Richard J A Goodwin, Per E Andrén
There is a high need to develop quantitative imaging methods capable of providing detailed brain localization information of several molecular species simultaneously. In addition, extensive information on the effect of the blood-brain barrier on the penetration, distribution and efficacy of neuroactive compounds is required. Thus, we have developed a mass spectrometry imaging method to visualize and quantify the brain distribution of drugs with varying blood-brain barrier permeability. With this approach, we were able to determine blood-brain barrier transport of different drugs and define the drug distribution in very small brain structures (e...
January 9, 2018: NeuroImage
Yu Luo, Guillén Fernández, Erno Hermans, Susanne Vogel, Yu Zhang, Hong Li, Floris Klumpers
Stress-related disorders, e.g., anxiety and depression, are characterized by decreased top-down control for distracting information, as well as a memory bias for threatening information. However, it is unclear how acute stress biases mnemonic encoding and leads to prioritized storage of threat-related information even if outside the focus of attention. In the current study, healthy adults (N = 53, all male) were randomly assigned to stress induction using the socially evaluated cold-pressor test (SECPT) or a control condition...
January 9, 2018: NeuroImage
Antonio Kolossa, Bruno Kopp
We analyzed factors that may hamper the advancement of computational cognitive neuroscience (CCN). These factors include a particular statistical mindset, which paves the way for the dominance of statistical power theory and a preoccupation with statistical replicability in the behavioral and neural sciences. Exclusive statistical concerns about sampling error occur at the cost of an inadequate representation of the problem of measurement error. We contrasted the manipulation of data quantity (sampling error, by varying the number of subjects) against the manipulation of data quality (measurement error, by varying the number of data per subject) in a simulated Bayesian model identifiability study...
January 9, 2018: NeuroImage
Yuyao Zhang, Hongjiang Wei, Matthew J Cronin, Naying He, Fuhua Yan, Chunlei Liu
Longitudinal brain atlases play an important role in the study of human brain development and cognition. Existing atlases are mainly based on anatomical features derived from T1-and T2-weighted MRI. A 4D developmental quantitative susceptibility mapping (QSM) atlas may facilitate the estimation of age-related iron changes in deep gray matter nuclei and myelin changes in white matter. To this end, group-wise co-registered QSM templates were generated over various age intervals from age 1-83 years old. Registration was achieved by combining both T1-weighted and QSM images...
January 8, 2018: NeuroImage
Curtis L Johnson, Hillary Schwarb, Kevin M Horecka, Matthew D J McGarry, Charles H Hillman, Arthur F Kramer, Neal J Cohen, Aron K Barbey
Brain tissue mechanical properties, measured in vivo with magnetic resonance elastography (MRE), have proven to be sensitive metrics of neural tissue integrity. Recently, our group has reported on the positive relationship between viscoelasticity of the hippocampus and performance on a relational memory task in healthy young adults, which highlighted the potential of sensitive MRE measures for studying brain health and its relation to cognitive function; however, structure-function relationships outside of the hippocampus have not yet been explored...
January 6, 2018: NeuroImage
Yaniv Assaf
The cortical layers define the architecture of the gray matter and its neuroanatomical regions and are essential for brain function. Abnormalities in cortical layer development, growth patterns, organization, or size can affect brain physiology and cognition. Unfortunately, while large population studies are underway that will greatly increase our knowledge about these processes, current non-invasive techniques for characterizing the cortical layers remain inadequate. For decades, high-resolution T1 and T2 Weighted Magnetic Resonance Imaging (MRI) have been the method-of-choice for gray matter and layer characterization...
January 5, 2018: NeuroImage
Pranav G Reddy, Marcelo G Mattar, Andrew C Murphy, Nicholas F Wymbs, Scott T Grafton, Theodore D Satterthwaite, Danielle S Bassett
Learning requires the traversal of inherently distinct cognitive states to produce behavioral adaptation. Yet, tools to explicitly measure these states with non-invasive imaging - and to assess their dynamics during learning - remain limited. Here, we describe an approach based on a novel application of graph theory in which points in time are represented by network nodes, and similarities in brain states between two different time points are represented as network edges. We use a graph-based clustering technique to identify clusters of time points representing canonical brain states, and to assess the manner in which the brain moves from one state to another as learning progresses...
January 5, 2018: NeuroImage
Natalia Z Bielczyk, Fabian Walocha, Patrick W Ebel, Koen V Haak, Alberto Llera, Jan K Buitelaar, Jeffrey C Glennon, Christian F Beckmann
Functional connectivity has been shown to be a very promising tool for studying the large-scale functional architecture of the human brain. In network research in fMRI, functional connectivity is considered as a set of pair-wise interactions between the nodes of the network. These interactions are typically operationalized through the full or partial correlation between all pairs of regional time series. Estimating the structure of the latent underlying functional connectome from the set of pair-wise partial correlations remains an open research problem though...
January 5, 2018: NeuroImage
Soroosh Afyouni, Thomas E Nichols
Estimates of functional connectivity using resting state functional Magnetic Resonance Imaging (rs-fMRI) are acutely sensitive to artifacts and large scale nuisance variation. As a result much effort is dedicated to preprocessing rs-fMRI data and using diagnostic measures to identify bad scans. One such diagnostic measure is DVARS, the spatial root mean square of the data after temporal differencing. A limitation of DVARS however is the lack of concrete interpretation of the absolute values of DVARS, and finding a threshold to distinguish bad scans from good...
January 4, 2018: NeuroImage
Franz Hell, Paul C J Taylor, Jan H Mehrkens, Kai Bötzel
Inhibitory control is an important executive function that is necessary to suppress premature actions and to block interference from irrelevant stimuli. Current experimental studies and models highlight proactive and reactive mechanisms and claim several cortical and subcortical structures to be involved in response inhibition. However, the involved structures, network mechanisms and the behavioral relevance of the underlying neural activity remain debated. We report cortical EEG and invasive subthalamic local field potential recordings from a fully implanted sensing neurostimulator in Parkinson's patients during a stimulus- and response conflict task with and without deep brain stimulation (DBS)...
January 4, 2018: NeuroImage
Francesca C Fortenbaugh, David Rothlein, Regina McGlinchey, Joseph DeGutis, Michael Esterman
Novel paradigms have allowed for more precise measurements of sustained attention ability and fluctuations in sustained attention over time, as well as the neural basis of fluctuations and lapses in performance. However, in recent years, concerns have arisen over the replicability of neuroimaging studies and psychology more broadly, particularly given the typically small sample sizes. One recently developed paradigm, the gradual-onset continuous performance task (gradCPT) has been validated behaviorally in large samples of participants...
January 4, 2018: NeuroImage
Sini Hämäläinen, Niko Mäkelä, Viljami Sairanen, Minna Lehtonen, Teija Kujala, Alina Leminen
Despite numerous functional neuroimaging and intraoperative electrical cortical mapping studies aimed at investigating the cortical organisation of native (L1) and second (L2) language processing, the neural underpinnings of bilingualism remain elusive. We investigated whether the neural network engaged in speech production over the bilateral posterior inferior frontal gyrus (pIFG) is the same (i.e., shared) or different (i.e., language-specific) for the two languages of bilingual speakers. Navigated transcranial magnetic stimulation (TMS) was applied over the left and right posterior inferior gyrus (pIFG), while early simultaneous bilinguals performed a picture naming task with their native languages...
January 3, 2018: NeuroImage
Catherine Lebel, Sean Deoni
Throughout infancy, childhood, and adolescence, our brains undergo remarkable changes. Processes including myelination and synaptogenesis occur rapidly across the first 2-3 years of life, and ongoing brain remodeling continues into young adulthood. Studies have sought to characterize the patterns of structural brain development, and early studies predominately relied upon gross anatomical measures of brain structure, morphology, and organization. MRI offers the ability to characterize and quantify a range of microstructural aspects of brain tissue that may be more closely related to fundamental neurodevelopmental processes...
January 3, 2018: NeuroImage
Luis Hernandez-Garcia, Anish Lahiri, Jonas Schollenberger
This article aims to provide the reader with an overview of recent developments in Arterial Spin Labeling (ASL) MRI techniques. A great deal of progress has been made in recent years in terms of the SNR and acquisition speed. New strategies have been introduced to improve labeling efficiency, reduce artefacts, and estimate other relevant physiological parameters besides perfusion. As a result, ASL techniques has become a reliable workhorse for researchers as well as clinicians. After a brief overview of the technique's fundamentals, this article will review new trends and variants in ASL including vascular territory mapping and velocity selective ASL, as well as arterial blood volume imaging techniques...
January 2, 2018: NeuroImage
Mark D Does
MRI relaxometry is sensitive to a variety of tissue characteristics in a complex manner, which makes it both attractive and challenging for characterizing tissue. This article reviews the most common water proton relaxometry measures, T1, T2, and T2*, and reports on their development and current potential to probe the composition and microstructure of brain tissue. The development of these relaxometry measures is challenged by the need for suitably accurate tissue models, as well as robust acquisition and analysis methodologies...
January 2, 2018: NeuroImage
Genta Ochi, Yuhki Yamada, Kazuki Hyodo, Kazuya Suwabe, Takemune Fukuie, Kyeongho Byun, Ippeita Dan, Hideaki Soya
While accumulating evidence suggests positive effects of exercise on executive function, such effects vary with environment. In particular, exercise in a hypoxic environment (hypobaric or normobaric hypoxia), leading to decreased oxygen supply, may dampen or cancel such effects. Thus, we further explore the relation between the effects of hypoxic exercise on executive function and their underlying neural mechanisms by monitoring changes of cortical activation patterns using functional near-infrared spectroscopy (fNIRS)...
January 2, 2018: NeuroImage
Sam J Gilbert, Hoki Fung
Previous studies using multi-voxel pattern analysis have decoded the content of participants' delayed intentions from patterns of fMRI data. Here we investigate whether this technique can be used to decode not only participants' own intentions, but also their representation of the intentions held by other people. In other words: if Sam is thinking about Hoki, can we decode the content of Hoki's intention by scanning Sam's brain? We additionally distinguished two components of intentions: action-plans versus goals, and included novel control analyses that allowed us to distinguish intending an outcome from simply expecting it to occur or simulating its consequences...
January 2, 2018: NeuroImage
Gregor Wilbertz, Madhura Ketkar, Matthias Guggenmos, Philipp Sterzer
The phenomenon of bistable perception, in which perception alternates spontaneously despite constant sensory stimulation, has been particularly useful in probing the neural bases of conscious perception. The study of such bistability requires access to the observer's perceptual dynamics, which is usually achieved via active report. This report, however, constitutes a confounding factor in the study of conscious perception and can also be biased in the context of certain experimental manipulations. One approach to circumvent these problems is to track perceptual alternations using signals from the eyes or the brain instead of observers' reports...
December 30, 2017: NeuroImage
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