Veronica Maki-Marttunen*, Ibai Diez*, Jesus M. Cortes, Dante R. Chialvo and Mirta Villarreal (*Equal contribution). Disruption of transfer entropy and inter-hemispheric brain functional connectivity in patients with disorder of consciousness. Frontiers in Neuroinformatics 7:24, 2013 [pdf] Severe traumatic brain injury can lead to disorders of consciousness (DOC) characterized by deficit in conscious awareness and cognitive impairment including coma, vegetative state, minimally consciousness, and lock-in syndrome. Of crucial importance is to […]
Jesus M Cortes*, Mathieu Desroches*, Serafim Rodrigues*, Romain Veltz , Miguel A. Muñoz and Terrence J. Sejnowski (* Equal Contribution). Short-term synaptic plasticity in the deterministic Tsodyks-Markram model leads to unpredictable network dynamics. Proc Natl Acad Sci USA 110:16610-16615, 2013 [pdf] Short-term synaptic plasticity strongly affects the neural dynamics of cortical networks. The Tsodyks and Markram (TM) model for short-term synaptic plasticity accurately accounts for a wide range of physiological […]
D. Marinazzo, M. Pellicoro, Guo-Rong Wu, L. Angelini, J.M. Cortes and S. Stramaglia. Information Transfer and Criticality in the Ising Model on the Human Connectome. PLoS One 9: e93616, 2014 [pdf] We implement the Ising model on a structural connectivity matrix describing the brain at two different resolutions. Tuning the model temperature to its critical value, i.e. at the susceptibility peak, we find a maximal amount of total information transfer […]
Ildefonso M. de la Fuente, Jesus M. Cortes, David A. Pelta, Juan Veguillas. Attractor Metabolic Networks. PLoS One 8: e58284, 2013 [pdf] Background The experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a Systemic Metabolic Structure in the cell, characterized by a set of different enzymatic reactions always locked into active states (metabolic core) while the […]
J.M. Cortes, A. Lopez, R. Molina and A.K. Katsaggelos. Variational Bayesian localization of EEG sources with generalized Gaussian priors. EPJ-Plus 127: 140, 2012 [pdf] Front cover [pdf] Although in the last decades the use of Magnetic Resonance Imaging has grown in popularity as a tool for the structural analysis of the brain, including MRI, fMRI and recently DTI, the ElectroEncephaloGraphy (EEG) is still-today an interesting technique for the understanding of […]
Jorge Hidalgo, Luis F Seoane, Jesus M Cortes and Miguel A Munoz. Stochastic amplification of fluctuations in cortical up-states. PLoS ONE 7: e40710, 2012 [pdf] Cortical neurons are bistable; as a consequence their local field potentials can fluctuate between quiescent and active states, generating slow 0.5-2 Hz oscillations which are widely known as transitions between Up and Down States. Despite a large number of studies on Up-Down transitions, deciphering its […]
Ildefonso M. De la Fuente, Jesus M. Cortes, Martin-Blas Perez-Pinilla, Vicente Ruiz-Rodriguez and Juan Veguillas. The metabolic core and catalytic switches are fundamental elements in the self-regulation of the Systemic Metabolic Structure of Cells. PLoS ONE 6:e27224, 2011 [pdf] Background. Experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a metabolic core formed by a set of […]
Ildefonso M. De la Fuente and Jesus M. Cortes. Quantitative analysis of the effective inter-enzyme connectivity in glycolysis. PLoS ONE 7:e30162, 2012 [pdf] Yeast glycolysis is considered the prototype of dissipative biochemical oscillator. In cellular conditions, under sinusoidal source of glucose, the activity of enzymes can display either periodic, quasi-periodic or chaotic behavior. By means of a system of non-linear differential equations with delay we have obtained different time series […]
J. M. Cortes, D. Marinazzo, P. Series, M.W. Oram, T.J. Sejnowski and M.C.W. van Rossum. The effect of neural adaptation on population coding accuracy. Journal of Computational Neuroscience 32:387-402, 2012 [pdf] Most neurons in the primary visual cortex initially respond vigorously when a preferred stimulus is presented, but adapt as stimulation continues. The functional consequences of adaptation are unclear. Typically a reduction of firing rate would reduce single neuron accuracy […]
J.M. Cortes, A. Greve, A. Barrett and M.C.W. van Rossum. Dynamics and Robustness of Familiarity Memory. Neural Computation 22: 448-466, 2010 [pdf] When presented with an item or a face, one might have a sense of recognition without the ability to recall when or where the stimulus has been encountered before. This sense of recognition is called familiarity memory. Following previous computational studies of familiarity memory, we investigate the dynamical […]
J.J. Torres, J. Marro, J.M. Cortes and B. Wemmenhove. Instabilities in attractor networks with fast synaptic fluctuations and partial updating of the neurons activity. Neural Networks 21: 1272-1277, 2008 [pdf] We present and study a probabilistic neural automaton in which the fraction of simultaneously-updated neurons is a parameter, rhoin(0,1). For small rho, there is relaxation towards one of the attractors and a great sensibility to external stimuli and, for rho […]
J. Marro, J.J. Torres and J.M. Cortes. Complex behavior in a network with time-dependent connections and silent nodes. Journal of Statistical Mechanics P02017, 2008 [pdf] We studied, both analytically and numerically, excitable networks in which connections are time-dependent and some of the nodes remain silent at each time step, and we show that these two features may induce intriguing functional complexity. More specifically, we consider (a) a heterogeneous distribution of […]
J.M.A.M. Kusters, J.M. Cortes, W.P.M. van Meerwijk, D.L. Ypey, A.P.R. Theuvenet and C.C.A.M. Gielen. Hysteresis and bi-stability by an interplay of calcium oscillations and action potential firing. Physical Review Letters 98: 098107, 2007. Nomination of PRL HighLights in the Magazine The Biological Physicist 7, April 2007 [pdf] Many cells reveal oscillatory behavior. Some cells reveal action-potential firing resulting from Hodgkin-Huxley (HH) type dynamics of ion channels in the cell membrane. […]
J. Marro, J.J. Torres and J.M. Cortes. Networks with Heterogeneously Weighted Connections and Partial Synchronization of Nodes. Computer Physics Communications 177: 180-183, 2007 [pdf] A network of stochastic nodes in which connections are heterogeneously weighted and dynamics may by varied from single-node updating to full synchronization as in familiar cellular automata is studied concerning computational strategies and states of attention in the brain.
J.J. Torres, J. M. Cortes, J. Marro and H.J. Kappen. Attractor Neural Networks with Activity-Dependent Synapses: The Role of Synaptic Facilitation. Neurocomputing 70: 2022-2025, 2007 [pdf] We studied an autoassociative neural network with dynamic synapses which include a facilitating mechanism. We have developed a general mean-field framework to study the relevance of the different parameters defining the dynamics of the synapses and their influence on the collective properties of the […]
J. Marro, J.J. Torres and J.M. Cortes. Chaotic hopping between attractors in neural automata. Neural Networks 20: 230-235, 2007 [pdf] We present a neurobiologically-inspired stochastic cellular automaton whose state jumps with time between the attractors corresponding to a series of stored patterns. The jumping varies from regular to chaotic as the model parameters are modified. The resulting irregular behavior, which mimics the state of attention in which a system shows […]
J.J. Torres, J.M. Cortes, J. Marro and H.J. Kappen. Competition between synaptic depression and facilitation in attractor neural networks. Neural Computation 19: 2739-2755, 2007 [pdf] We study the effect of competition between short-term synaptic depression and facilitation on the dynamic properties of attractor neural networks, using Monte Carlo simulation and a mean-field analysis. Depending on the balance of depression, facilitation, and the underlying noise, the network displays different behaviors, including […]
J. M. Cortes, J. Marro and J. J. Torres. Control of neural chaos by synaptic noise. Biosystems 87: 186-190, 2007 [pdf] We study neural automata or neurobiologically inspired cellular automata which exhibits chaotic itinerancy among the different stored patterns or memories. This is a consequence of activity-dependent synaptic fluctuations, which continuously destabilize the attractor and induce irregular hopping to other possible attractors. The nature of these irregularities depends on the […]
J. M. Cortes, J. J. Torres, J. Marro, P. L. Garrido and H. J. Kappen. Effects of fast presynaptic noise in attractor neural networks. Neural Computation 18: 614-633, 2006 [pdf] We study both analytically and numerically the effect of presynaptic noise on the transmission of information in attractor neural networks. The noise occurs on a very short timescale compared to that for the neuron dynamics and it produces short-time synaptic […]
J. J. Torres, J. Marro, P. L. Garrido, J. M. Cortes, F. Ramos and M. A. Munoz. Effects of static and dynamic disorder on the performance of neural automata. Biophysical Chemistry 115: 285-288, 2005 [pdf] We report on both analytical and numerical results concerning stochastic Hopfield-like neural automata exhibiting the following (biologically inspired) features: (1) Neurons and synapses evolve in time as in contact with respective baths at different temperatures; […]
Sebastiano Stramaglia, Leonardo Angelini, Jesus M. Cortes and Daniele Marinazzo. Synergy, redundancy and unnormalized Granger causality. EMBS 4037-4040, 2015 [arXiv:1504.03584] [pdf]
S. Stramaglia, J.M. Cortes, L. Angelini, M. Pellicoro and D. Marinazzo. Information flow in Ising models on brain networks. V.M. Mladenov and P.C. Ivanov (Eds.): NDES 2014, CCIS 438, pp. 301–308, 2014 [pdf]. We analyze the information flow in the Ising model on two real networks, describing the brain at the mesoscale, with Glauber dynamics. We find that the critical state is characterized by the maximal amount of information flow […]
J. Hidalgo, L.F. Seoane, J.M. Cortes and M.A. Muñoz. Does the phenomenon of stochastic amplification of fluctuations play a relevant role in cortical dynamics? AIP Conference Proceedings 1510: 94-100, 2012 [pdf] We review the mechanism of stochastic amplification of fluctuations in the context of fast cortical oscillations observed during up-states both in vitro and in vivo. For this purpose, we employ minimalistic models based on short-time synaptic depression with or […]
A. Lopez, J.M. Cortes, D. Lopez-Oller, R. Molina and A.K. Katsaggelos. Hyperparameters Estimation for the Bayesian Localization of the EEG Sources with TV Priors. EUSIPCO 2012: 20th European Signal Processing Conference , pags 489-493, 2012 [pdf] In this work we propose a new Bayesian method for the non-invasive localization of EEG sources. For this problem, most of the existing methods assume that the sources are distributed throughout the brain volume […]
J.M. Cortes, D. Marinazzo, T.J. Sejnowski and M.C.W. van Rossum. The Direction of Tilt Aftereffects Depends on Short-term Inhibitory Facilitation. NIPS 2011, Submitted but Rejected [pdf] Neural adaptation leads to changes in the responses of single neurons and neural populations during continued exposure to a stimulus. At the single neuron level, adaptation reduces responses to a constant stimulus. At the perceptual level, adaptation can manifest itself as aftereffects. For instance, […]
J.M. Cortes. Interfaces cerebro-maquina, un gran paso hacia la Inteligencia Artificial. Ciencia Cognitiva: Revista Electronica de Divulgacion 3: 24-26, 2009 [pdf] Dentro de la Neurociencia Computacional, la Neuro-ingeniería desarrolla sistemas de comunicación entre una máquina y alguna parte del sistema nervioso. Sin lugar a dudas, estos sistemas constituyen un gran reto científico, ingenieril y ético. Sin embargo, su correcto funcionamiento todavía plantea muchos problemas.
J.M. Cortes. La Neurociencia Computacional hoy: I. Que es y por que es dificil su estudio. Ciencia Cognitiva: Revista Electronica de Divulgacion 3: 5-7, 2009 [pdf] La Neurociencia Computacional es una disciplina consolidada, con más de 20 años de desarrollo, y que emplea técnicas muy diversas para entender diferentes computaciones cerebrales. Aquí se introduce brevemente mediante dos artículos. En el primero, “Qué es y por qué es difícil su estudio”, […]
J.M. Cortes. La Neurociencia Computacional hoy: II. Un ejemplo muy representativo en el campo. Ciencia Cognitiva: Revista Electronica de Divulgacion 3: 8-11, 2009 [pdf] La Neurociencia Computacional es un campo reciente, pero bien establecido dentro de las Neurociencias. En un primer artículo Cortes 2009, “Qué es y por qué es difícil su estudio”, explico su principal paradigma: todo proceso mental que tiene lugar en nuestro cerebro tiene un circuito o […]
J.M.A.M. Kusters, J.M. Cortes, W.P.M. van Meerwijk, D.L.Ypey, A.P.R. Theuvenet and C.C.A.M. Gielen. Oscillatory activity in cells: multi-stability and hysteresis. AIP Conference Proceedings 887: 40-50, 2007 [pdf] Oscillatory activity of cells has been the topic of many studies. Oscillatory activity can be due to action potential firing corresponding to the well-known Hodgkin-Huxley (HH) type dynamics of ion-channels in the cell membrane or due to IP3-mediated calcium oscillations in the endoplasmic […]
J.J. Torres, J. M. Cortes and J. Marro. Information processing with unstable memories. AIP Conference Proceedings 887: 115-128, 2007 [pdf] We present a theoretical framework which allows one to study both theoretically and numerically the effect of including activity dependent mechanisms in the dynamics of synapses in simple neural networks. In particular, we study synaptic changes at different time scales from less than the millisecond (fast synaptic noise) to the […]