History-Dependent Excitability as a Single-Cell Substrate of Transient Memory for Information Discrimination

Abstract

Neurons react differently to incoming stimuli depending upon their previous history of stimulation. This property can be considered as a single-cell substrate for transient memory, or context-dependent information processing: depending upon the current context that the neuron “sees” through the subset of the network impinging on it in the immediate past, the same synaptic event can evoke a postsynaptic spike or just a subthreshold depolarization. We propose a formal definition of History-Dependent Excitability (HDE) as a measure of the propensity to firing in any moment in time, linking the subthreshold history-dependent dynamics with spike generation. This definition allows the quantitative assessment of the intrinsic memory for different single-neuron dynamics and input statistics. We illustrate the concept of HDE by considering two general dynamical mechanisms: the passive behavior of an Integrate and Fire (IF) neuron, and the inductive behavior of a Generalized Integrate and Fire (GIF) neuron with subthreshold damped oscillations. This framework allows us to characterize the sensitivity of different model neurons to the detailed temporal structure of incoming stimuli. While a neuron with intrinsic oscillations discriminates equally well between input trains with the same or different frequency, a passive neuron discriminates better between inputs with different frequencies. This suggests that passive neurons are better suited to rate-based computation, while neurons with subthreshold oscillations are advantageous in a temporal coding scheme. We also address the influence of intrinsic properties in single-cell processing as a function of input statistics, and show that intrinsic oscillations enhance discrimination sensitivity at high input rates. Finally, we discuss how the recognition of these cell-specific discrimination properties might further our understanding of neuronal network computations and their relationships to the distribution and functional connectivity of different neuronal types.

Removal of Default State-Associated Inhibition during Repetition Priming Improves Response Articulation

“…6). Excitability modulation has been demonstrated in a number of systems as a mechanism by which recent history can implement longer lasting temporal dynamics in the response properties of a neuron (Byrne and Kandel, 1996; Destexhe and Marder, 2004; Baroni et al, 2010; Steinert et al, 2011). Our data, in combination with previous work on the cellular mechanisms underlying repetition priming (Friedman and Weiss, 2010), suggest that multiple mechanisms induce changes in motor neuron excitability and that their implementation may be segregated based on functional traits of target motor neurons.…”

Analysis of mobile applications that help skin care through facial recognition: A systematic analysis

“…De 31 publicaciones referenciadas en el presente trabajo, 18 informan de sistemas que aplican tecnologías que diagnostican enfermedades de la piel, la mayor parte de referencias lo hacen mediante un algoritmos, métodos y herramientas [24,25]; 5 documentos aportan a la tele dermatología como una tecnología para el diagnóstico y cuidado de la piel mediante asistencia remota, para el desarrollo de estos sistemas se han aplicado métodos y modelos ayudan al autocuidado de la piel [26], reconocimiento de lesiones [27]; 2 obras tratan de aplicaciones móviles desarrollada para el cuidado de la piel [28,29] estos pueden analizar imágenes de la piel y dar un diagnóstico de las posibles patologías; y finalmente 3 obras tratan de aplicaciones móviles mismos que mediante un teléfono inteligente pueden notificar recomendaciones adecuadas para el cuidado de la piel en base al índice ultravioleta (UVI) [30], hay aplicaciones que desarrollan conductas de prevención del cáncer de piel [5], e incluyen aplicaciones asisten al cuidado de la piel de personas con espina bífida que son más propenso a lesiones cutáneas [31].…”

Neural dynamics based on the recognition of neural fingerprints

“…Model simulations support the hypothesis that intraburst neural signatures could be part of a multiplexed code where the neuron identity could be transmitted together with the circumstantial message (Latorre et al, 2006 , 2007 ). Readers of these signals can take advantage of these multiple simultaneous codes and process them one by one or simultaneously to perform different tasks (Latorre et al, 2006 ; Baroni et al, 2010 ). Thus, if a neural system is able to recognize different neural fingerprints in its input signals and adjust its behavior to them, it could discriminate or contextualize their inputs as a function of general aspect of the signal like specific interspike frequencies via resonance (Izhikevich et al, 2003 ;), but also as a function of a specific emitter or task.…”