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Michael S Beauchamp - One of the best experts on this subject based on the ideXlab platform.
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converging evidence from electrocorticography and bold fmri for a sharp Functional Boundary in superior temporal gyrus related to multisensory speech processing
Frontiers in Human Neuroscience, 2018Co-Authors: Muge Ozker, Daniel Yoshor, Michael S BeauchampAbstract:Although humans can understand speech using the auditory modality alone, in noisy environments visual speech information from the talker's mouth can rescue otherwise unintelligible auditory speech. To investigate the neural substrates of multisensory speech perception, we compared neural activity from the human superior temporal gyrus in two datasets. One dataset consisted of direct neural recordings (electrocorticography, ECoG) from surface electrodes implanted in epilepsy patients (this dataset has been previously published). The second dataset consisting of indirect measures of neural activity using blood oxygen level dependent Functional magnetic resonance imaging (BOLD fMRI). Both ECoG and fMRI participants viewed the same clear and noisy audiovisual speech stimuli and performed the same speech recognition task. Both techniques demonstrated a sharp Functional Boundary in the STG, spatially coincident with an anatomical Boundary defined by the posterior edge of Heschl's gyrus. Cortex on the anterior side of the Boundary responded more strongly to clear audiovisual speech than to noisy audiovisual speech while cortex on the posterior side of the Boundary did not. For both ECoG and fMRI measurements, the transition between the Functionally distinct regions happened within 10 mm of anterior-to-posterior distance along the STG. We relate this Boundary to the multisensory neural code underlying speech perception and propose that it represents an important Functional division within the human speech perception network.
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converging evidence from electrocorticography and bold fmri for a sharp Functional Boundary in superior temporal gyrus related to multisensory speech processing
bioRxiv, 2018Co-Authors: Michael S Beauchamp, Muge OzkerAbstract:Although humans can understand speech using the auditory modality alone, in noisy environments visual speech information from the talker's mouth can rescue otherwise unintelligible auditory speech. To investigate the neural substrates of multisensory speech perception, we recorded neural activity from the human superior temporal gyrus using two very different techniques: either directly, using surface electrodes implanted in five participants with epilepsy (electrocorticography, ECOG), or indirectly, using blood oxygen level dependent Functional magnetic resonance imaging (BOLD fMRI) in six healthy control fMRI participants. Both ECOG and fMRI participants viewed the same clear and noisy audiovisual speech stimuli and performed the same speech recognition task. Both techniques demonstrated a sharp Functional Boundary in the STG, which corresponded to an anatomical Boundary defined by the posterior edge of Heschl's gyrus. On the anterior side of the Boundary, cortex responded more strongly to clear audiovisual speech than to noisy audiovisual speech, suggesting that anterior STG is primarily involved in processing unisensory auditory speech. On the posterior side of the Boundary, cortex preferred noisy audiovisual speech or showed no preference and showed robust responses to auditory-only and visual-only speech, suggesting that posterior STG is specialized for processing multisensory audiovisual speech. For both ECOG and fMRI, the transition between the Functionally distinct regions happened within 10 mm of anterior-to-posterior distance along the STG. We relate this Boundary to the multisensory neural code underlying speech perception and propose that it represents an important Functional division within the human speech perception network.
Kimmo Tuominen - One of the best experts on this subject based on the ideXlab platform.
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Mass anomalous dimension of SU(2) using the spectral density method
arXiv: High Energy Physics - Lattice, 2016Co-Authors: Joni M. Suorsa, Viljami Leino, Jarno Rantaharju, Teemu Rantalaiho, Kari Rummukainen, Kimmo Tuominen, Sara TähtinenAbstract:SU(2) with N_f = 6 and N_f = 8 are believed to have an infrared conformal fixed point. We use the spectral density method cross referenced with the mass step scaling method to evaluate the coupling constant dependence of the mass anomalous dimension for massless HEX smeared, clover improved Wilson fermions with Schr\"odinger Functional Boundary conditions.
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Mass anomalous dimension of SU(2) with Nf=8 using the spectral density method
arXiv: High Energy Physics - Lattice, 2015Co-Authors: Joni M. Suorsa, Viljami Leino, Jarno Rantaharju, Teemu Rantalaiho, Kari Rummukainen, Kimmo Tuominen, David J. WeirAbstract:SU(2) with Nf=8 is believed to have an infrared conformal fixed point. We use the spectral density method to evaluate the coupling constant dependence of the mass anomalous dimension for massless HEX smeared, clover improved Wilson fermions with Schr\"odinger Functional Boundary conditions.
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Effect of the Schrödinger Functional Boundary conditions on the convergence of step scaling
Proceedings of The 30th International Symposium on Lattice Field Theory — PoS(Lattice 2012), 2012Co-Authors: Tuomas Karavirta, Kari Rummukainen, Kimmo TuominenAbstract:Recently several lattice collaborations have studied the scale dependence of the coupling in theories with different gauge groups and fermion representations using the Schrodinger Functional method. This has motivated us to look at the convergence of the perturbative step scaling to its continuum limit with gauge groups SU(2) and SU(3) with Wilson fermions in the fundamental, adjoint or sextet representations. We have found that while the improved Wilson action does remove the linear terms from the step scaling, the convergence is extremely slow with the standard choices of the Boundary conditions for the background field. We show that the situation can be improved by careful choice of the Boundary fields.
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Effect of the Schr\"odinger Functional Boundary conditions on the convergence of step scaling
arXiv: High Energy Physics - Lattice, 2012Co-Authors: Tuomas Karavirta, Kari Rummukainen, Kimmo TuominenAbstract:Recently several lattice collaborations have studied the scale dependence of the coupling in theories with different gauge groups and fermion representations using the Schr\"odinger Functional method. This has motivated us to look at the convergence of the perturbative step scaling to its continuum limit with gauge groups SU(2) and SU(3) with Wilson fermions in the fundamental, adjoint or sextet representations. We have found that while the improved Wilson action does remove the linear terms from the step scaling, the convergence is extremely slow with the standard choices of the Boundary conditions for the background field. We show that the situation can be improved by careful choice of the Boundary fields.
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Perturbative improvement of SU(2) gauge theory with two Wilson fermions in the adjoint representation
arXiv: High Energy Physics - Lattice, 2010Co-Authors: Tuomas Karavirta, Jarno Rantaharju, Kari Rummukainen, Anne-mari Mykkanen, Kimmo TuominenAbstract:We present a perturbative calculation of the improvement coefficients of SU(2) gauge theory with adjoint representation Wilson-clover fermions and using Schrodinger Functional Boundary conditions. The computation of the Boundary improvement terms is necessary for the full O(a) improvement. With two flavours of adjoint representation fermions this theory is called Minimal Walking Technicolor model.
Muge Ozker - One of the best experts on this subject based on the ideXlab platform.
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converging evidence from electrocorticography and bold fmri for a sharp Functional Boundary in superior temporal gyrus related to multisensory speech processing
Frontiers in Human Neuroscience, 2018Co-Authors: Muge Ozker, Daniel Yoshor, Michael S BeauchampAbstract:Although humans can understand speech using the auditory modality alone, in noisy environments visual speech information from the talker's mouth can rescue otherwise unintelligible auditory speech. To investigate the neural substrates of multisensory speech perception, we compared neural activity from the human superior temporal gyrus in two datasets. One dataset consisted of direct neural recordings (electrocorticography, ECoG) from surface electrodes implanted in epilepsy patients (this dataset has been previously published). The second dataset consisting of indirect measures of neural activity using blood oxygen level dependent Functional magnetic resonance imaging (BOLD fMRI). Both ECoG and fMRI participants viewed the same clear and noisy audiovisual speech stimuli and performed the same speech recognition task. Both techniques demonstrated a sharp Functional Boundary in the STG, spatially coincident with an anatomical Boundary defined by the posterior edge of Heschl's gyrus. Cortex on the anterior side of the Boundary responded more strongly to clear audiovisual speech than to noisy audiovisual speech while cortex on the posterior side of the Boundary did not. For both ECoG and fMRI measurements, the transition between the Functionally distinct regions happened within 10 mm of anterior-to-posterior distance along the STG. We relate this Boundary to the multisensory neural code underlying speech perception and propose that it represents an important Functional division within the human speech perception network.
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converging evidence from electrocorticography and bold fmri for a sharp Functional Boundary in superior temporal gyrus related to multisensory speech processing
bioRxiv, 2018Co-Authors: Michael S Beauchamp, Muge OzkerAbstract:Although humans can understand speech using the auditory modality alone, in noisy environments visual speech information from the talker's mouth can rescue otherwise unintelligible auditory speech. To investigate the neural substrates of multisensory speech perception, we recorded neural activity from the human superior temporal gyrus using two very different techniques: either directly, using surface electrodes implanted in five participants with epilepsy (electrocorticography, ECOG), or indirectly, using blood oxygen level dependent Functional magnetic resonance imaging (BOLD fMRI) in six healthy control fMRI participants. Both ECOG and fMRI participants viewed the same clear and noisy audiovisual speech stimuli and performed the same speech recognition task. Both techniques demonstrated a sharp Functional Boundary in the STG, which corresponded to an anatomical Boundary defined by the posterior edge of Heschl's gyrus. On the anterior side of the Boundary, cortex responded more strongly to clear audiovisual speech than to noisy audiovisual speech, suggesting that anterior STG is primarily involved in processing unisensory auditory speech. On the posterior side of the Boundary, cortex preferred noisy audiovisual speech or showed no preference and showed robust responses to auditory-only and visual-only speech, suggesting that posterior STG is specialized for processing multisensory audiovisual speech. For both ECOG and fMRI, the transition between the Functionally distinct regions happened within 10 mm of anterior-to-posterior distance along the STG. We relate this Boundary to the multisensory neural code underlying speech perception and propose that it represents an important Functional division within the human speech perception network.
Feliz Minhós - One of the best experts on this subject based on the ideXlab platform.
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First Order Coupled Systems With Functional and Periodic Boundary Conditions: Existence Results and Application to an SIRS Model
Axioms, 2019Co-Authors: João Fialho, Feliz MinhósAbstract:The results presented in this paper deal with the existence of solutions of a first order fully coupled system of three equations, and they are split in two parts: 1. Case with coupled Functional Boundary conditions, and 2. Case with periodic Boundary conditions. Functional Boundary conditions, which are becoming increasingly popular in the literature, as they generalize most of the classical cases and in addition can be used to tackle global conditions, such as maximum or minimum conditions. The arguments used are based on the Arzela Ascoli theorem and Schauder’s fixed point theorem. The existence results are directly applied to an epidemic SIRS (Susceptible-Infectious-Recovered-Susceptible) model, with global Boundary conditions.
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Sufficient conditions for the solvability of some third order Functional Boundary value problems on the half-line
Commentationes Mathematicae Universitatis Carolinae, 2018Co-Authors: Hugo Carrasco, Feliz MinhósAbstract:This paper is concerned with the existence of bounded or unbounded solutions to third-order Boundary value problem on the half-line with Functional Boundary conditions. The arguments are based on the Green functions, a Nagumo condition, Schauder fixed point theorem and lower and upper solutions method. An application to a Falkner-Skan equation with Functional Boundary conditions is given to illustrate our results.
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Extremal solutions to fourth order discontinuous Functional Boundary value problems
Mathematische Nachrichten, 2013Co-Authors: Alberto Cabada, João Fialho, Feliz MinhósAbstract:In this paper, given a L1-Caratheodory function, it is considered the Functional fourth order equation together with the nonlinear Functional Boundary conditions Here , , satisfy some adequate monotonicity assumptions and are not necessarily continuous functions. It will be proved an existence and location result in presence of non ordered lower and upper solutions.
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Higher order Functional Boundary value problems without monotone assumptions
Boundary Value Problems, 2013Co-Authors: João Fialho, Feliz MinhósAbstract:In this paper, given f : [ a , b ] × ( C ( [ a , b ] ) ) n − 2 × R 2 → R Open image in new window a L 1 Open image in new window-Caratheodory function, it is considered the Functional higher order equation
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New Trends on Nonlocal and Functional Boundary Value Problems
Journal of Function Spaces and Applications, 2013Co-Authors: Gennaro Infante, Feliz MinhósAbstract:In the last decades, Boundary value problems with nonlocal and Functional Boundary conditions have become a rapidly growing area of research. The study of this type of problems not only has a theoretical interest that includes a huge variety of differential, integrodifferential, and abstract equations, but also is motivated by the fact that these problems can be used as a model for several phenomena in engineering, physics, and life sciences that standard Boundary conditions cannot describe. In this framework, fall problems with feedback controls, such as the steady states of a thermostat, where a controller at one of its ends adds or removes heat depending upon the temperature registered in another point, or phenomena with Functional dependence in the equation and/or in the Boundary conditions, with delays or advances, maximum or minimum arguments, such as beams where the maximum (minimum) of the deflection is attained in some interior or endpoint of the beam. Topological and Functional analysis tools, for example, degree theory, fixed point theorems, or variational principles, have played a key role in the developing of this subject. This volume contains a variety of contributions within this area of research. The articles deal with second and higher order Boundary value problems with nonlocal and Functional conditions for ordinary, impulsive, partial, and fractional differential equations on bounded and unbounded domains. In the contributions, existence, uniqueness, and asymptotic behaviour of solutions are considered by using several methods as fixed point theorems, spectral analysis, and oscillation theory. Acknowledgments
Alberto Cabada - One of the best experts on this subject based on the ideXlab platform.
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Extremal solutions to fourth order discontinuous Functional Boundary value problems
Mathematische Nachrichten, 2013Co-Authors: Alberto Cabada, João Fialho, Feliz MinhósAbstract:In this paper, given a L1-Caratheodory function, it is considered the Functional fourth order equation together with the nonlinear Functional Boundary conditions Here , , satisfy some adequate monotonicity assumptions and are not necessarily continuous functions. It will be proved an existence and location result in presence of non ordered lower and upper solutions.
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Non ordered lower and upper solutions to fourth order problems with Functional Boundary conditions
Conference Publications 2011, 2011Co-Authors: Alberto Cabada, João Fialho, Feliz MinhósAbstract:In this paper, given $f : I \times (C(I))^2 \times \mathbb{R}^2 \leftarrow \mathbb{R}$ a $L^1$ Caratheodory function, it is considered the Functional fourth order equation $u^(iv) (x) = f(x, u, u', u'' (x), u''' (x))$ together with the nonlinear Functional Boundary conditions $L_0(u, u', u'', u (a)) = 0 = L_1(u, u', u'', u' (a))$ $L_2(u, u', u'', u'' (a), u''' (a)) = 0 = L_3(u, u', u'', u'' (b}, u''' (b)):$ Here $L_i, i$ = 0; 1; 2; 3, are continuous functions satisfying some adequate monotonicity assumptions. It will be proved an existence and location result in presence of non ordered lower and upper solutions and without monotone assumptions on the right hand side of the equation.
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Nonlinear second-order equations with Functional implicit impulses and nonlinear Functional Boundary conditions
Nonlinear Analysis: Theory Methods & Applications, 2011Co-Authors: Alberto Cabada, Bevan ThompsonAbstract:Abstract In this paper we present existence results for solutions of nonlinear second-order Boundary value problems with impulses. Our impulses are applied at p points in the interval and given implicitly by nonlinear functions of the solution. Moreover we allow Functional dependence on the solution. Our existence results follow from the existence of a pair of well ordered lower and upper solutions. We generalize earlier results of Cabada and Tomec˘ek, allowing more general compatible Boundary conditions, impulses and φ -Laplacian equations.
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Extremal solutions to fourth-order Functional Boundary value problems including multipoint conditions
Nonlinear Analysis: Real World Applications, 2009Co-Authors: Alberto Cabada, Rodrigo L. Pouso, Feliz MinhósAbstract:Abstract This paper concerns the fully fourth-order nonlinear Functional equation (E) − d d t ( ϕ ∘ u ‴ ) ( t ) = f ( t , u ″ ( t ) , u ‴ ( t ) , u , u ′ , u ″ ) , for a.a. t ∈ I = [ a , b ] , with the Functional Boundary conditions (BC) B 1 ( u ( b ) , u , u ′ , u ″ ) = 0 = B 2 ( u ′ ( b ) , u , u ′ , u ″ ) , B 3 ( u ″ ( a ) , u ″ ( b ) , u ‴ ( a ) , u ‴ ( b ) , u , u ′ , u ″ ) = 0 = L 2 ( u ″ ( a ) , u ″ ( b ) ) , where ϕ : R ⟶ R is an increasing homeomorphism, f : I × R 2 × ( C ( I ) ) 3 ⟶ R , B i , i = 1 , 2 , 3 , and L 2 are suitable functions. The existence of extremal solutions for problem (E) -(BC) is proved by defining a convenient partial ordering. Some sufficient conditions to obtain lower and upper solutions are given.
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Fully nonlinear fourth-order equations with Functional Boundary conditions
Journal of Mathematical Analysis and Applications, 2008Co-Authors: Alberto Cabada, Feliz MinhósAbstract:Abstract The aim of this paper consists in to give sufficient conditions to ensure the existence and location of the solutions of a nonlinear fully fourth-order equation with Functional Boundary conditions. The arguments make use of the upper and lower solutions method, a ϕ -Laplacian operator and a fixed point theorem. An application of the beam theory to a nonlinear continuous model of the human spine allows to estimate its deformation under some loading forces.
