3,711 research outputs found
In Favour of Machines (But Not Forgetting the Workers): Some Considerations on the Fourth Industrial Revolution
No full textThis chapter aims to guide the reader in the analysis of some of the main themes proposed by the debate related to the Fourth Industrial Revolution (4IR). First, we discuss the impact of the 4IR on employment by reviewing the results of the relevant economic literature, drawing some suggestions for future research. Second, we review some of the policies developed by governments to support the digital revolution. We argue that while Industry 4.0-type policies are common to all advanced countries, policies in favour of digital technologies in the service sector are more fragmented, difficult to implement, and face a stronger resistance from workers. We finish the paper with a discussion of the main policy issues related to the workers and the labour market, with a focus on robot tax, shared robot ownership, and universal basic income. We conclude by emphasizing that while policies in favour of machines are widespread and supported by wide social consensus, effective polices in favour of workers are much weaker and still unable to mitigate the negative effects of the digital revolution
Action potential processing in a detailed Purkinje cell model reveals a critical role for axonal compartmentalization
No full textThe Purkinje cell (PC) is among the most complex neurons in the brain and plays a critical role for cerebellar functioning. PCs operate as fast pacemakers modulated by synaptic inputs but can switch from simple spikes to complex bursts and, in some conditions, show bistability. In contrast to original works emphasizing dendritic Ca-dependent mechanisms, recent experiments have supported a primary role for axonal Na-dependent processing, which could effectively regulate spike generation and transmission to deep cerebellar nuclei (DCN). In order to account for the numerous ionic mechanisms involved (at present including Nav1.6, Cav2.1, Cav3.1, Cav3.2, Cav3.3, Kv1.1, Kv1.5, Kv3.3, Kv3.4, Kv4.3, KCa1.1, KCa2.2, KCa3.1, Kir2.x, HCN1), we have elaborated a multicompartmental model incorporating available knowledge on localization and gating of PC ionic channels. The axon, including initial segment (AIS) and Ranvier nodes (RNs), proved critical to obtain appropriate pacemaking and firing frequency modulation. Simple spikes initiated in the AIS and protracted discharges were stabilized in the soma through Na-dependent mechanisms, while somato-dendritic Ca channels contributed to sustain pacemaking and to generate complex bursting at high discharge regimes. Bistability occurred only following Na and Ca channel down-regulation. In addition, specific properties in RNs K currents were required to limit spike transmission frequency along the axon. The model showed how organized electroresponsive functions could emerge from the molecular complexity of PCs and showed that the axon is fundamental to complement ionic channel compartmentalization enabling action potential processing and transmission of specific spike patterns to DCN
Ensemble neuronal responses in a large-scale realistic model of the cerebellar cortex
No full textRealistic simulation of central networks remains a challenge due to the complexity of internal connectivity and cellular mechanisms involved. We have recently built a realistic model of the cerebellar granular layer..
Il contributo di Sergio Torsello alla renaissance salentina del primo quindicennio del 2000
No full textQuesto contributo mira a descrivere le tre “anime” di Sergio Torsello – Direttore Artistico del Festival La Notte della Taranta, Consulente Scientifico dell’Istituto Diego Carpitella, e Mediatore Culturale tra e per i talenti artistici del suo territorio. Il punto di partenza della narrazione è un articolo di Sergio Torsello, pubblicato nel 2011 in un volume di cui l’autore della narrazione è stato curatore. L’autore sottolinea la stretta connessione tra le tre anime di Sergio Torsello, che emerge non solo dal suo articolo del 2011 ma anche dalle numerose interazioni avvenute tra Sergio Torsello e l’autore. La descrizione del rilievo scientifico della figura di Sergio Torsello è sicuramente parziale, circoscritta nel tempo (gli 8 anni, dal 2007 al 2015 in cui ha interagito con l’autore) e nello spazio (inteso come insieme di argomenti delle loro conversazioni scientifiche e culturali). Ma rende merito del cruciale contributo di Sergio Torsello alla renaissance culturale salentina degli anni dal 2001 al 2015.This contribution aims to describe the three “souls” of Sergio Torsello – Artistic Director of “La Notte della Taranta” Festival, Scientific Consultant of “Diego Carpitella” Institute, and Cultural Mediator
between and for the artistic talents of his territory. The starting point of the description is an article by Sergio Torsello, published in 2011 in a book of which the author of the description was the editor. The author highlights the close connection between the three souls of Sergio Torsello, which emerges not only from the above-mentioned article, but also from the numerous interactions between Sergio Torsello and the author. The description of the scientific significance of Sergio Torsello’s figure is certainly partial, limited in time (the 8 years, from 2007 to 2015, in which he interacted with the author) and in space (in terms of set of topics of their scientific and cultural conversations). But it gives merit to Sergio Torsello’s key contribution to the cultural renaissance of Salento in the years from 2001 to 2015
A hybrid model for the computationally-efficient simulation of the cerebellar granular layer
No full textThe aim of the present paper is to efficiently describe the membrane potential dynamics of neural populations formed by species having a high density difference in specific brain areas. We propose a hybrid model whose main ingredients are a conductance-based model (ODE system) and its continuous counterpart (PDE system) obtained through a limit process in which the number of neurons confined in a bounded region of the brain tissue is sent to infinity. Specifically, in the discrete model, each cell is described by a set of time-dependent variables, whereas in the continuum model, cells are grouped into populations that are described by a set of continuous variables.Communications between populations, which translate into interactions among the discrete and the continuous models, are the essence of the hybrid model we present here. The cerebellum and cerebellum-like structures show in their granular layer a large difference in the relative density of neuronal species making them a natural testing ground for our hybrid model. By reconstructing the ensemble activity of the cerebellar granular layer network and by comparing our results to a more realistic computational network, we demonstrate that our description of the network activity, even though it is not biophysically detailed, is still capable of reproducing salient features of neural network dynamics. Our modeling approach yields a significant computational cost reduction by increasing the simulation speed at least times. The hybrid model reproduces interesting dynamics such as local microcircuit synchronization, traveling waves, center-surround and time-windowing
High-Voltage-Activated Calcium Channels
No full textThe annual Computational Neuroscience Meeting (CNS) began in 1990 as a small workshop called Analysis and Modeling of Neural Systems. The goal of the workshop was to explore the boundary between neuroscience and computation. Riding on the success of several seminal papers, physicists had made "Neural Networks" fashionable, and soon the quantitative methods used in these abstract model networks started permeating the methods and ideas of experimental neuroscientists. Although experimental neurophysiological approaches provided many advances, it became increasingly evident that mathematical and computational techniques would be required to achieve a comprehensive and quantitative understanding of neural system function. “Computational Neuroscience” emerged to complement experimental neurophysiology. In 2002, the non-profit organization, Organization for Computational Neuroscience (OCNS) was formed. OCNS has now become the first professional society serving the global computational neuroscience community. OCNS as a society lives at the interface where experimental neuroscience meets theoretical, statistical and computer-simulation analyses, with the hope of turning large collections of experimental results into a principled understanding of nervous systems. It also supports the development of new engineering, computational and informatics techniques for data collection, analyses and management
Fast-reset of pacemaking and theta-frequency resonance patterns in cerebellar golgi cells: Simulations of their impact <I>in vivo</I>
No full textThe Golgi cells are inhibitory interneurons of the cerebellar granular layer, which respond to afferent stimulation in vivo with a burst-pause sequence interrupting their irregular background low-frequency firing (Vos et al., 1999a. Eur. J. Neurosci. 11, 2621–2634). However, Golgi cells in vitro are regular pacemakers (Forti et al., 2006. J. Physiol. 574, 711–729), raising the question how their ionic mechanisms could impact on responses during physiological activity. Using patch-clamp recordings in cerebellar slices we show that the pacemaker cycle can be suddenly reset by spikes, making the cell highly sensitive to input variations. Moreover, the neuron resonates around the pacemaker frequency, making it specifically sensitive to patterned stimulation in the theta-frequency band. Computational analysis based on a model developed to reproduce Golgi cell pacemaking (Solinas et al., 2008 Front. Neurosci., 1:2) predicted that phase-reset required spike-triggered activation of SK channels and that resonance was sustained by a slow voltage-dependent potassium current and amplified by a persistent sodium current. Adding balanced synaptic noise to mimic the irregular discharge observed in vivo, we found that pacemaking converts into spontaneous irregular discharge, that phase-reset plays an important role in generating the burst-pause pattern evoked by sensory stimulation, and that repetitive stimulation at theta-frequency enhances the time-precision of spike coding in the burst. These results suggest that Golgi cell intrinsic properties exert a profound impact on time-dependent signal processing in the cerebellar granular layer
Computational reconstruction of pacemaking and intrinsic electroresponsiveness in cerebellar golgi cells
No full textThe Golgi cells have been recently shown to beat regularly in vitro (Forti et al., 2006. J. Physiol. 574, 711-729). Four main currents were shown to be involved, namely a persistent sodium current (INa-p), an h current (Ih), an SK-type calcium-dependent potassium current (IK-AHP), and a slow M-like potassium current (IK-slow). These ionic currents could take part, together with others, also to different aspects of neuronal excitability like responses to depolarizing and hyperpolarizing current injection. However, the ionic mechanisms and their interactions remained largely hypothetical. In this work, we have investigated the mechanisms of Golgi cell excitability by developing a computational model. The model predicts that pacemaking is sustained by subthreshold oscillations tightly coupled to spikes. INa-p and IK-slow emerged as the critical determinants of oscillations. Ih also played a role by setting the oscillatory mechanism into the appropriate membrane potential range. IK-AHP, though taking part to the oscillation, appeared primarily involved in regulating the ISI following spikes. The combination with other currents, in particular a resurgent sodium current (INa-r) and an A-current (IK-A), allowed a precise regulation of response frequency and delay. These results provide a coherent reconstruction of the ionic mechanisms determining Golgi cell intrinsic electroresponsiveness and suggests important implications for cerebellar signal processing, which will be fully developed in a companion paper (Solinas et al., 2008. Front. Neurosci. 1:4)
Stochastic Generalized Nash Equilibrium-Seeking in Merely Monotone Games
No full textWe solve the stochastic generalized Nash equilibrium (SGNE) problem in merely monotone games with expected value cost functions. Specifically, we present the first distributed SGNE-seeking algorithm for monotone games that require one proximal computation (e.g., one projection step) and one pseudogradient evaluation per iteration. Our main contribution is to extend the relaxed forward–backward operator splitting by the Malitsky (Mathematical Programming, 2019) to the stochastic case and in turn to show almost sure convergence to an SGNE when the expected value of the pseudogradient is approximated by the average over a number of random samples.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Sergio GrammaticoTeam Bart De Schutte
Sergio Bettini e la critica d’arte
No full textOn the occasion of the publication of two books about Sergio Bettini’s works (unpublished studies, conference proceedings and critical apparatus) the author analyzes the scientific production of this scholar during his life (1930-1986). Furtherly this essay analyzes the great scholar’s relationship with the School of Wien and first of all his deep connection with all European different critical and comparative points of view
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