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https://www.readbyqxmd.com/read/28439231/informing-the-structure-of-executive-function-in-children-a-meta-analysis-of-functional-neuroimaging-data
#1
Róisín McKenna, T Rushe, Kate A Woodcock
The structure of executive function (EF) has been the focus of much debate for decades. What is more, the complexity and diversity provided by the developmental period only adds to this contention. The development of executive function plays an integral part in the expression of children's behavioral, cognitive, social, and emotional capabilities. Understanding how these processes are constructed during development allows for effective measurement of EF in this population. This meta-analysis aims to contribute to a better understanding of the structure of executive function in children...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28439014/brain-networks-for-confidence-weighting-and-hierarchical-inference-during-probabilistic-learning
#2
Florent Meyniel, Stanislas Dehaene
Learning is difficult when the world fluctuates randomly and ceaselessly. Classical learning algorithms, such as the delta rule with constant learning rate, are not optimal. Mathematically, the optimal learning rule requires weighting prior knowledge and incoming evidence according to their respective reliabilities. This "confidence weighting" implies the maintenance of an accurate estimate of the reliability of what has been learned. Here, using fMRI and an ideal-observer analysis, we demonstrate that the brain's learning algorithm relies on confidence weighting...
April 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28434861/representation-of-multiple-body-parts-in-the-missing-hand-territory-of-congenital-one-handers
#3
Avital Hahamy, Scott N Macdonald, Fiona van den Heiligenberg, Paullina Kieliba, Uzay Emir, Rafael Malach, Heidi Johansen-Berg, Peter Brugger, Jody C Culham, Tamar R Makin
Individuals born without one hand (congenital one-handers) provide a unique model for understanding the relationship between focal reorganization in the sensorimotor cortex and everyday behavior. We previously reported that the missing hand's territory of one-handers becomes utilized by its cortical neighbor (residual arm representation), depending on residual arm usage in daily life to substitute for the missing hand's function [1, 2]. However, the repertoire of compensatory behaviors may involve utilization of other body parts that do not cortically neighbor the hand territory...
April 19, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28431740/getting-a-grip-on-reality-grasping-movements-directed-to-real-objects-and-images-rely-on-dissociable-neural-representations
#4
Erez Freud, Scott N Macdonald, Juan Chen, Derek J Quinlan, Melvyn A Goodale, Jody C Culham
In the current era of touchscreen technology, humans commonly execute visually guided actions directed to two-dimensional (2D) images of objects. Although real, three-dimensional (3D), objects and images of the same objects share high degree of visual similarity, they differ fundamentally in the actions that can be performed on them. Indeed, previous behavioral studies have suggested that simulated grasping of images relies on different representations than actual grasping of real 3D objects. Yet the neural underpinnings of this phenomena have not been investigated...
March 18, 2017: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
https://www.readbyqxmd.com/read/28426802/decoding-the-infant-mind-multivariate-pattern-analysis-mvpa-using-fnirs
#5
Lauren L Emberson, Benjamin D Zinszer, Rajeev D S Raizada, Richard N Aslin
The MRI environment restricts the types of populations and tasks that can be studied by cognitive neuroscientists (e.g., young infants, face-to-face communication). FNIRS is a neuroimaging modality that records the same physiological signal as fMRI but without the constraints of MRI, and with better spatial localization than EEG. However, research in the fNIRS community largely lacks the analytic sophistication of analogous fMRI work, restricting the application of this imaging technology. The current paper presents a method of multivariate pattern analysis for fNIRS that allows the authors to decode the infant mind (a key fNIRS population)...
2017: PloS One
https://www.readbyqxmd.com/read/28420788/reconstructing-the-spectrotemporal-modulations-of-real-life-sounds-from-fmri-response-patterns
#6
Roberta Santoro, Michelle Moerel, Federico De Martino, Giancarlo Valente, Kamil Ugurbil, Essa Yacoub, Elia Formisano
Ethological views of brain functioning suggest that sound representations and computations in the auditory neural system are optimized finely to process and discriminate behaviorally relevant acoustic features and sounds (e.g., spectrotemporal modulations in the songs of zebra finches). Here, we show that modeling of neural sound representations in terms of frequency-specific spectrotemporal modulations enables accurate and specific reconstruction of real-life sounds from high-resolution functional magnetic resonance imaging (fMRI) response patterns in the human auditory cortex...
April 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28413706/basic-taste-processing-recruits-bilateral-anteroventral-and-middle-dorsal-insulae-an-activation-likelihood-estimation-meta-analysis-of-fmri-studies
#7
Andy Wai Kan Yeung, Tazuko K Goto, Wai Keung Leung
BACKGROUND AND PURPOSE: Numerous task-based functional magnetic resonance imaging (fMRI) studies have reported the locations of basic taste representations in the human brain, but they usually employed a limited number of subjects (<20) with different methodologies and stimuli. Moreover, the reported brain regions were sometimes inconsistent. Thus, we aimed at performing a meta-analysis of the published data to identify locations consistently activated across studies, and performed a connectivity analysis to reveal how these taste processing regions connect with other brain regions...
April 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28403383/neural-signatures-of-cognitive-flexibility-and-reward-sensitivity-following-nicotinic-receptor-stimulation-in-dependent-smokers-a-randomized-trial
#8
Elise Lesage, Sarah E Aronson, Matthew T Sutherland, Thomas J Ross, Betty Jo Salmeron, Elliot A Stein
Importance: Withdrawal from nicotine is an important contributor to smoking relapse. Understanding how reward-based decision making is affected by abstinence and by pharmacotherapies such as nicotine replacement therapy and varenicline tartrate may aid cessation treatment. Objective: To independently assess the effects of nicotine dependence and stimulation of the nicotinic acetylcholine receptor on the ability to interpret valence information (reward sensitivity) and subsequently alter behavior as reward contingencies change (cognitive flexibility) in a probabilistic reversal learning task...
April 12, 2017: JAMA Psychiatry
https://www.readbyqxmd.com/read/28392488/improved-7-tesla-resting-state-fmri-connectivity-measurements-by-cluster-based-modeling-of-respiratory-volume-and-heart-rate-effects
#9
Joana Pinto, Sandro Nunes, Marta Bianciardi, Afonso Dias, L Miguel Silveira, Lawrence L Wald, Patrícia Figueiredo
Several strategies have been proposed to model and remove physiological noise from resting-state fMRI (rs-fMRI) data, particularly at ultrahigh fields (7 T), including contributions from respiratory volume (RV) and heart rate (HR) signal fluctuations. Recent studies suggest that these contributions are highly variable across subjects and that physiological noise correction may thus benefit from optimization at the subject or even voxel level. Here, we systematically investigated the impact of the degree of spatial specificity (group, subject, newly proposed cluster, and voxel levels) on the optimization of RV and HR models...
April 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/28384099/a-decomposition-model-and-voxel-selection-framework-for-fmri-analysis-to-predict-neural-response-of-visual-stimuli
#10
Savita V Raut, Dinkar M Yadav
This paper presents an fMRI signal analysis methodology using geometric mean curve decomposition (GMCD) and mutual information-based voxel selection framework. Previously, the fMRI signal analysis has been conducted using empirical mean curve decomposition (EMCD) model and voxel selection on raw fMRI signal. The erstwhile methodology loses frequency component, while the latter methodology suffers from signal redundancy. Both challenges are addressed by our methodology in which the frequency component is considered by decomposing the raw fMRI signal using geometric mean rather than arithmetic mean and the voxels are selected from EMCD signal using GMCD components, rather than raw fMRI signal...
April 6, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28375210/corticolimbic-hyper-response-to-emotion-and-glutamatergic-function-in-people-with-high-schizotypy-a-multimodal-fmri-mrs-study
#11
G Modinos, A McLaughlin, A Egerton, K McMullen, V Kumari, G J Barker, C Keysers, S C R Williams
Animal models and human neuroimaging studies suggest that altered levels of glutamatergic metabolites within a corticolimbic circuit have a major role in the pathophysiology of schizophrenia. Rodent models propose that prefrontal glutamate dysfunction could lead to amygdala hyper-response to environmental stress and underlie hippocampal overdrive in schizophrenia. Here we determine whether changes in brain glutamate are present in individuals with high schizotypy (HS), which refers to the presence of schizophrenia-like characteristics in healthy individuals, and whether glutamate levels are related to altered corticolimbic response to emotion...
April 4, 2017: Translational Psychiatry
https://www.readbyqxmd.com/read/28373123/sensitivity-and-specificity-considerations-for-fmri-encoding-decoding-and-mapping-of-auditory-cortex-at-ultra-high-field
#12
Michelle Moerel, Federico De Martino, Valentin G Kemper, Sebastian Schmitter, An T Vu, Kâmil Uğurbil, Elia Formisano, Essa Yacoub
Following rapid technological advances, ultra-high field functional MRI (fMRI) enables exploring correlates of neuronal population activity at an increasing spatial resolution. However, as the fMRI blood-oxygenation-level-dependent (BOLD) contrast is a vascular signal, the spatial specificity of fMRI data is ultimately determined by the characteristics of the underlying vasculature. At 7T, fMRI measurement parameters determine the relative contribution of the macro- and microvasculature to the acquired signal...
March 31, 2017: NeuroImage
https://www.readbyqxmd.com/read/28367256/investigating-differences-in-brain-functional-networks-using-hierarchical-covariate-adjusted-independent-component-analysis
#13
Ran Shi, Ying Guo
Human brains perform tasks via complex functional networks consisting of separated brain regions. A popular approach to characterize brain functional networks in fMRI studies is independent component analysis (ICA), which is a powerful method to reconstruct latent source signals from their linear mixtures. In many fMRI studies, an important goal is to investigate how brain functional networks change according to specific clinical and demographic variabilities. Existing ICA methods, however, cannot directly incorporate covariate effects in ICA decomposition...
December 2016: Annals of Applied Statistics
https://www.readbyqxmd.com/read/28364005/presurgical-brain-mapping-of-the-ventral-somatomotor-network-in-patients-with-brain-tumors-using-resting-state-fmri
#14
N Yahyavi-Firouz-Abadi, J J Pillai, M A Lindquist, V D Calhoun, S Agarwal, R D Airan, B Caffo, B Gujar, H I Sair
BACKGROUND AND PURPOSE: Resting-state fMRI readily identifies the dorsal but less consistently the ventral somatomotor network. Our aim was to assess the relative utility of resting-state fMRI in the identification of the ventral somatomotor network via comparison with task-based fMRI in patients with brain tumor. MATERIALS AND METHODS: We identified 26 surgically na|fkve patients referred for presurgical fMRI brain mapping who had undergone both satisfactory ventral motor activation tasks and resting-state fMRI...
March 31, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28363450/a-new-method-for-independent-component-analysis-with-priori-information-based-on-multi-objective-optimization
#15
Yuhu Shi, Weiming Zeng, Nizhuan Wang, Le Zhao
BACKGROUND: Currently the problem of incorporating priori information into an independent component analysis (ICA) model is often solved under the framework of constrained ICA, which utilizes the priori information as a reference signal to form a constraint condition and then introduce it into classical ICA. However, it is difficult to pre-determine a suitable threshold parameter to constrain the closeness between the output signal and the reference signal in the constraint condition...
March 29, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28363248/the-resting-state-fmri-regional-homogeneity-reho-metrics-kcc-reho-cohe-reho-are-valid-indicators-of-tumor-related-neurovascular-uncoupling
#16
Shruti Agarwal, Haris I Sair, Jay J Pillai
AIM: To determine whether regional homogeneity (ReHo) of resting state BOLD fMRI (rsfMRI) data based on Kendall's coefficient of concordance (KCC-ReHo) & Coherence (Cohe-ReHo) metrics may allow detection of brain tumor-induced NVU in the sensorimotor network similar to findings in standard motor task-based BOLD fMRI (tbfMRI) activation. METHODS: Twelve de novo brain tumor patients undergoing clinical fMRI exams (tbfMRI and rsfMRI) were included in this IRB-approved study...
March 31, 2017: Brain Connectivity
https://www.readbyqxmd.com/read/28362834/the-impact-of-inspired-oxygen-levels-on-calibrated-fmri-measurements-of-m-oef-and-resting-cmro2-using-combined-hypercapnia-and-hyperoxia
#17
Isabelle Lajoie, Felipe B Tancredi, Richard D Hoge
Recent calibrated fMRI techniques using combined hypercapnia and hyperoxia allow the mapping of resting cerebral metabolic rate of oxygen (CMRO2) in absolute units, oxygen extraction fraction (OEF) and calibration parameter M (maximum BOLD). The adoption of such technique necessitates knowledge about the precision and accuracy of the model-derived parameters. One of the factors that may impact the precision and accuracy is the level of oxygen provided during periods of hyperoxia (HO). A high level of oxygen may bring the BOLD responses closer to the maximum M value, and hence reduce the error associated with the M interpolation...
2017: PloS One
https://www.readbyqxmd.com/read/28348512/using-dual-regression-to-investigate-network-shape-and-amplitude-in-functional-connectivity-analyses
#18
Lisa D Nickerson, Stephen M Smith, Döst Öngür, Christian F Beckmann
Independent Component Analysis (ICA) is one of the most popular techniques for the analysis of resting state FMRI data because it has several advantageous properties when compared with other techniques. Most notably, in contrast to a conventional seed-based correlation analysis, it is model-free and multivariate, thus switching the focus from evaluating the functional connectivity of single brain regions identified a priori to evaluating brain connectivity in terms of all brain resting state networks (RSNs) that simultaneously engage in oscillatory activity...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28345153/the-functional-architectures-of-addition-and-subtraction-network-discovery-using-fmri-and-dcm
#19
Yang Yang, Ning Zhong, Karl Friston, Kazuyuki Imamura, Shengfu Lu, Mi Li, Haiyan Zhou, Haiyuan Wang, Kuncheng Li, Bin Hu
The neuronal mechanisms underlying arithmetic calculations are not well understood but the differences between mental addition and subtraction could be particularly revealing. Using fMRI and dynamic causal modeling (DCM), this study aimed to identify the distinct neuronal architectures engaged by the cognitive processes of simple addition and subtraction. Our results revealed significantly greater activation during subtraction in regions along the dorsal pathway, including the left inferior frontal gyrus (IFG), middle portion of dorsolateral prefrontal cortex (mDLPFC), and supplementary motor area (SMA), compared with addition...
March 27, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28343986/the-hemodynamic-signal-as-a-first-order-low-pass-temporal-filter-evidence-and-implications-for-neuroimaging-studies
#20
Antoine Sauvage, Guillaume Hubert, Jonathan Touboul, Jérôme Ribot
Neuronal activation triggers local changes in blood flow and hemoglobin oxygenation. These hemodynamic signals can be recorded through functional magnetic resonance imaging or intrinsic optical imaging, and allows inferring neural activity in response to stimuli. These techniques are widely used to uncover functional brain architectures. However, their accuracy suffers from distortions inherent to hemodynamic responses and noise. The analysis of these signals currently relies on models of impulse hemodynamic responses to brief stimuli...
March 23, 2017: NeuroImage
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