Publications by authors named "Joaquin Torres"

We introduce the Visual Experience Dataset (VEDB), a compilation of more than 240 hours of egocentric video combined with gaze- and head-tracking data that offer an unprecedented view of the visual world as experienced by human observers. The dataset consists of 717 sessions, recorded by 56 observers ranging from 7 to 46 years of age. This article outlines the data collection, processing, and labeling protocols undertaken to ensure a representative sample and discusses the potential sources of error or bias within the dataset.

View Article and Find Full Text PDF

The relation between electroencephalography (EEG) rhythms, brain functions, and behavioral correlates is well-established. Some physiological mechanisms underlying rhythm generation are understood, enabling the replication of brain rhythms in silico. This offers a pathway to explore connections between neural oscillations and specific neuronal circuits, potentially yielding fundamental insights into the functional properties of brain waves.

View Article and Find Full Text PDF

Triadic interactions are higher-order interactions which occur when a set of nodes affects the interaction between two other nodes. Examples of triadic interactions are present in the brain when glia modulate the synaptic signals among neuron pairs or when interneuron axo-axonic synapses enable presynaptic inhibition and facilitation, and in ecosystems when one or more species can affect the interaction among two other species. On random graphs, triadic percolation has been recently shown to turn percolation into a fully fledged dynamical process in which the size of the giant component undergoes a route to chaos.

View Article and Find Full Text PDF

Background: Latin America has a high prevalence of Helicobacter pylori in children that may lead to peptic ulcer disease and eventually gastric cancer in adulthood. Successful eradication is hindered by rising antimicrobial resistance. We summarize H.

View Article and Find Full Text PDF

The properties of complex networked systems arise from the interplay between the dynamics of their elements and the underlying topology. Thus, to understand their behavior, it is crucial to convene as much information as possible about their topological organization. However, in large systems, such as neuronal networks, the reconstruction of such topology is usually carried out from the information encoded in the dynamics on the network, such as spike train time series, and by measuring the transfer entropy between system elements.

View Article and Find Full Text PDF
Article Synopsis
  • Recent advancements in neuroscience have enhanced our understanding of brain function, particularly through the study of neuron interactions and synaptic activity.
  • Essential cognitive processes, like consciousness and identity, emerge from complex networks of neurons working together and adapting to their environment.
  • The article highlights the relevance of physics concepts in brain activity and how these interactions can be observed in EEG recordings, linking them to significant phenomena in memory tasks.
View Article and Find Full Text PDF

We here study a network of synaptic relations mingling excitatory and inhibitory neuron nodes that displays oscillations quite similar to electroencephalogram (EEG) brain waves, and identify abrupt variations brought about by swift synaptic mediations. We thus conclude that corresponding changes in EEG series surely come from the slowdown of the activity in neuron populations due to synaptic restrictions. The latter happens to generate an imbalance between excitation and inhibition causing a quick explosive increase of excitatory activity, which turns out to be a (first-order) transition among dynamic mental phases.

View Article and Find Full Text PDF
Article Synopsis
  • The study explores how the interplay between structural changes and functional behavior in neural networks influences their ability to process and store information.
  • It demonstrates that a temporary phase of high synaptic connectivity is essential for memory recovery, especially in noisy environments, and that maintaining intermediate synaptic densities optimizes energy use during development.
  • The findings provide insights into the characteristic patterns of synaptic pruning in the brain and offer guidance for designing neural networks that mimic biological systems for enhanced information processing.
View Article and Find Full Text PDF
Article Synopsis
  • The higher-order interactions in complex systems like the brain are represented by simplicial complexes, influencing their dynamics significantly.
  • Existing models typically assume that dynamics occur only at the nodes, which limits their accuracy.
  • The new higher-order Kuramoto model allows for interactions on nodes, links, and triangles, demonstrating that it can lead to explosive synchronization through adaptive coupling strategies.
View Article and Find Full Text PDF

Here we study the emergence of chimera states, a recently reported phenomenon referring to the coexistence of synchronized and unsynchronized dynamical units, in a population of Morris-Lecar neurons which are coupled by both electrical and chemical synapses, constituting a hybrid synaptic architecture, as in actual brain connectivity. This scheme consists of a nonlocal network where the nearest neighbor neurons are coupled by electrical synapses, while the synapses from more distant neurons are of the chemical type. We demonstrate that peculiar dynamical behaviors, including chimera state and traveling wave, exist in such a hybrid coupled neural system, and analyze how the relative abundance of chemical and electrical synapses affects the features of chimera and different synchrony states (i.

View Article and Find Full Text PDF
Article Synopsis
  • The brain's structure dynamically evolves through the creation and elimination of synaptic connections between neurons, shaping how memories are formed and consolidated.
  • Recent models suggest that the processes of adding and removing synapses are influenced by both local neuronal activity and overall network connectivity, creating a feedback loop between brain structure and function.
  • This feedback leads to oscillating patterns in brain activity, which are linked to long-term memory storage mechanisms, as changes in synaptic structure can introduce noise, affecting memory retrieval and storage dynamics.
View Article and Find Full Text PDF

Recently there is a surge of interest in network geometry and topology. Here we show that the spectral dimension plays a fundamental role in establishing a clear relation between the topological and geometrical properties of a network and its dynamics. Specifically we explore the role of the spectral dimension in determining the synchronization properties of the Kuramoto model.

View Article and Find Full Text PDF

We observe and study a self-organized phenomenon whereby the activity in a network of spiking neurons spontaneously terminates. We consider different types of populations, consisting of bistable model neurons connected electrically by gap junctions, or by either excitatory or inhibitory synapses, in a scale-free connection topology. We find that strongly synchronized population spiking events lead to complete cessation of activity in excitatory networks, but not in gap junction or inhibitory networks.

View Article and Find Full Text PDF

The dynamics of networks of neuronal cultures has been recently shown to be strongly dependent on the network geometry and in particular on their dimensionality. However, this phenomenon has been so far mostly unexplored from the theoretical point of view. Here we reveal the rich interplay between network geometry and synchronization of coupled oscillators in the context of a simplicial complex model of manifolds called Complex Network Manifold.

View Article and Find Full Text PDF
Article Synopsis
  • Inverse Stochastic Resonance (ISR) shows that a neuron's average spiking rate can reach a minimum when noise is present, and this study explores ISR in scale-free networks.
  • The research employs Hodgkin-Huxley model neurons with channel noise and examines how network connections, like gap junctions and synapses, affect ISR.
  • Findings indicate that weak connectivity enhances ISR under certain conditions, especially highlighting that network structure plays a crucial role in the neuron's response to noise, which could inform experimental observations of ISR in real neuronal systems.
View Article and Find Full Text PDF

We investigate the behavior of a model neuron that receives a biophysically realistic noisy postsynaptic current based on uncorrelated spiking activity from a large number of afferents. We show that, with static synapses, such noise can give rise to inverse stochastic resonance (ISR) as a function of the presynaptic firing rate. We compare this to the case with dynamic synapses that feature short-term synaptic plasticity and show that the interval of presynaptic firing rate over which ISR exists can be extended or diminished.

View Article and Find Full Text PDF
Article Synopsis
  • The text includes a collection of research topics related to neural circuits, mental disorders, and computational models in neuroscience.
  • It features various studies examining the functional advantages of neural heterogeneity, propagation waves in the visual cortex, and dendritic mechanisms crucial for precise neuronal functioning.
  • The research covers a range of applications, from understanding complex brain rhythms to modeling auditory processing and investigating the effects of neural regulation on behavior.
View Article and Find Full Text PDF

In the last years, network scientists have directed their interest to the multi-layer character of real-world systems, and explicitly considered the structural and dynamical organization of graphs made of diverse layers between its constituents. Most complex systems include multiple subsystems and layers of connectivity and, in many cases, the interdependent components of systems interact through many different channels. Such a new perspective is indeed found to be the adequate representation for a wealth of features exhibited by networked systems in the real world.

View Article and Find Full Text PDF

In this paper we analyze the interplay between the subthreshold oscillations of a single neuron conductance-based model and the short-term plasticity of a dynamic synapse with a depressing mechanism. In previous research, the computational properties of subthreshold oscillations and dynamic synapses have been studied separately. Our results show that dynamic synapses can influence different aspects of the dynamics of neuronal subthreshold oscillations.

View Article and Find Full Text PDF

We here illustrate how a well-founded study of the brain may originate in assuming analogies with phase-transition phenomena. Analyzing to what extent a weak signal endures in noisy environments, we identify the underlying mechanisms, and it results a description of how the excitability associated to (non-equilibrium) phase changes and criticality optimizes the processing of the signal. Our setting is a network of integrate-and-fire nodes in which connections are heterogeneous with rapid time-varying intensities mimicking fatigue and potentiation.

View Article and Find Full Text PDF

We investigate the efficient transmission and processing of weak, subthreshold signals in a realistic neural medium in the presence of different levels of the underlying noise. Assuming Hebbian weights for maximal synaptic conductances--that naturally balances the network with excitatory and inhibitory synapses--and considering short-term synaptic plasticity affecting such conductances, we found different dynamic phases in the system. This includes a memory phase where population of neurons remain synchronized, an oscillatory phase where transitions between different synchronized populations of neurons appears and an asynchronous or noisy phase.

View Article and Find Full Text PDF

In this paper we review our research on the effect and computational role of dynamical synapses on feed-forward and recurrent neural networks. Among others, we report on the appearance of a new class of dynamical memories which result from the destabilization of learned memory attractors. This has important consequences for dynamic information processing allowing the system to sequentially access the information stored in the memories under changing stimuli.

View Article and Find Full Text PDF

Short-term memory in the brain cannot in general be explained the way long-term memory can--as a gradual modification of synaptic weights--since it takes place too quickly. Theories based on some form of cellular bistability, however, do not seem able to account for the fact that noisy neurons can collectively store information in a robust manner. We show how a sufficiently clustered network of simple model neurons can be instantly induced into metastable states capable of retaining information for a short time (a few seconds).

View Article and Find Full Text PDF

Here we numerically study the emergence of stochastic resonance as a mild phenomenon and how this transforms into an amazing enhancement of the signal-to-noise ratio at several levels of a disturbing ambient noise. The setting is a cooperative, interacting complex system modelled as an Ising-Hopfield network in which the intensity of mutual interactions or "synapses" varies with time in such a way that it accounts for, e.g.

View Article and Find Full Text PDF

The performance of attractor neural networks has been shown to depend crucially on the heterogeneity of the underlying topology. We take this analysis a step further by examining the effect of degree-degree correlations--assortativity--on neural-network behavior. We make use of a method recently put forward for studying correlated networks and dynamics thereon, both analytically and computationally, which is independent of how the topology may have evolved.

View Article and Find Full Text PDF