Study of sequential information processing in electroreception through modelling and closed-loop stimulation techniques

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Escuela Politécnica Superior, Departamento de Ingenieria Informática. Fecha de Lectura: 20-01-202

Estudio del procesamiento de información en peces eléctricos mediante técnicas lazo cerrado de estimulación en tiempo real

Los peces de la especie Gnathonemus Petersii hacen uso de la electrorrecepciónn activa (generación y detección de campos eléctricos) para la comunicación con otros individuos y la localización de objetos. Dichos procesos exigen un procesamiento de la información (codificación, decodificación...). El objetivo de este proyecto es comprender qué procesos básicos guían la actividad eléctrica del pez a la hora de comunicarse y orientarse. Para ello, se ha adaptado una plataforma hardware-software dedicada en tiempo real para la adquisición de la señal emitida por el sistema biológico y la estimulación artificial del mismo mediante técnicas en ciclo cerrado operando en tiempo real. Esto hace posible una interacción optima y controlada entre los dispositivos artificiales y los sistemas de procesamiento de información naturales del pez. Este modelo en ciclo cerrado resulta fundamental para caracterizar y extraer información del sistema en vivo. Además, en dicha plataforma se han implementado una serie de módulos y mejoras que permiten un mayor control de la actividad del pez y el uso de nuevos protocolos de estimulación en ciclo cerrado. Por otro lado, el uso de técnicas de teoría de la información ha permitido tanto caracterizar la actividad eléctrica del pez como estudiar cambios en el procesamiento de información. Dado un modelo de codificación de la información sobre la señal eléctrica del pez, el cálculo de la entropía sobre la serie de códigos resultante permite estudiar la capacidad de transmisión de información de dicha señal. Se ha realizado un estudio entrópico de la evolución de la actividad eléctrica del pez sin estimulación en periodos largos de tiempo que muestra variaciones en la entrop ía de la señal incluso en ausencia de estimulación artificial. Este estudio nos permite además seleccionar los parámetros para la digitalización que guiarán el establecimiento del ciclo cerrado en la estimulación dependiente de actividad dirigida por códigos. También se ha realizado un análisis (basado en el uso de una codificación digital binaria) sobre la influencia de una memoria a corto plazo. Mediante la implementación de un módulo de digitalización y binarización on-line de la señal adquirida, ha sido posible caracterizar la información en forma de códigos binarios y establecer en función de ellos un ciclo cerrado de estimulación. Los resultados de dicho análisis muestran variaciones en el procesamiento de información cuando la estimulación depende de la actividad eléctrica del pez en un rango de tiempo, lo que da indicios prometedores de la influencia de la memoria en el procesamiento de información. Finalmente, el uso de metodología estadística aplicada a la teoría matemática de la comunicación nos permite un análisis no lineal de los resultados, necesario para extraer información sobre los cambios en el procesamiento de información en función de la estimulación presentada.Active electro-reception (the generation and detection of electric elds) is used by Gnathonemus Petersii sh in order to communicate with other individuals and to locate objects. Such processes require an information processing (code, decode...). The aim of this work is to understand which processes guide the sh's electric activity so it would be able to communicate and orientate. During our investigation we have used a hardware-software platform to collect the signal emitted by the biological system and also to stimulate it by closed-loop techniques that operate in real time. This method allows a positive and controlled interaction between the arti cial mechanisms and the sh's natural systems of information processing. Such a closed-loop model is essential in the in vivo characterization and extraction of information from the sh. Additionally we have manage to implement a certain amount of modules and improvements on the platform which enable a better control of the sh's activity and the use of new closed-loop stimulation protocols. On the other hand, the characterization of the sh's electric activity and the study of the changes done during the information processing as well have been made possible by using techniques from the information theory. In that order, given a coding model of information over the sh's electric signal and having the entropy of the groups of codes calculated, the result evaluates the signal's capacity of data transmission. We have also made an entropic study of the development of the sh's activity with no stimulation during long time periods that shows entropy variations even in absence of stimulation. This study has enabled us to select the parameters for the digitalization which will lead the establishment of the closed-loop along the stimulation that depends on the activity run by codes. Furthermore, we have done an analysis about the in uence of a short-time memory based on a binary digital coding. Through the implementation of digitalization and binarization on-line module of the collected signal, it has been possible to characterize the information into binary codes by mean of which we have established closed-loop stimulation. These results show variations in the information processing when the stimulation takes shorttime range electrical activity into account, which provide promising indications about the in uence of the memory. In the end, using statistics applied into the mathematical theory of communication has allows us to make a non-lineal analysis of our study's results. Such type of research is essential for the extraction of information about the changes along the data processing which depends on the stimulation appeare

Modeling the sequential pattern variability of the electromotor command system of pulse electric fish

This study was supported by AEI/FEDER grants TIN2017-84452-R, PID2020-114867RB-I00, and PGC2018-095895-B-I0

Temporal code-driven stimulation: definition and application to electric fish signaling

This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permissionClosed-loop activity-dependent stimulation is a powerful methodology to assess information processing in biological systems. In this context, the development of novel protocols, their implementation in bioinformatics toolboxes and their application to different description levels open up a wide range of possibilities in the study of biological systems. We developed a methodology for studying biological signals representing them as temporal sequences of binary events. A specific sequence of these events (code) is chosen to deliver a predefined stimulation in a closed-loop manner. The response to this code-driven stimulation can be used to characterize the system. This methodology was implemented in a real time toolbox and tested in the context of electric fish signaling. We show that while there are codes that evoke a response that cannot be distinguished from a control recording without stimulation, other codes evoke a characteristic distinct response. We also compare the code-driven response to open-loop stimulation. The discussed experiments validate the proposed methodology and the software toolbox.This work was funded by Spanish projects of Ministerio de Economia y Competitividad/FEDER TIN-2010-19607, TIN2014-54580-R, TIN-2012-30883, DPI2015 65833-P (http://www.mineco.gob.es/), ONRG grant N62909-14-1-N279, Brazilian Agency of Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (http://www.cnpq.br/) and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (www.fapesp.br). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

Assessing Energy Descent Scenarios for the Ecological Transition in Spain 2020–2030

A global energy consumption reduction is essential to address the many dimensions of the current ecological crisis. In this paper we have compiled the reasons that justify the necessity to start this energy descent process in the countries of the global North, where the annual per capita final energy consumption was 118 GJ in 2017. Based on recent research, we approach the necessary redistribution of energy consumption at the global level and the elements that should be present in energy descent strategies. We establish an approximate threshold of minimum and maximum per capita final energy consumption, between 15.6 GJ and 31.0 GJ for the year 2050, which serves as a reference for evaluating scenarios. We continue with an analysis of two ecological transition scenarios for Spain between 2020 and 2030, Green New Deal and Degrowth. Based on a schematic calculation model defined in “Labor Scenarios in the Ecosocial Transition 2020–2030” report, we evaluate the variations in energy consumption for 86 sectors of economic activity. Results show an annual final energy consumption per capita in 2030 of 44.6 GJ and 36.8 GJ for each scenario. We conclude by analyzing the hypothetical main drivers of this sharp decline in energy consumption

BtM, a Low-cost Open-source Datalogger to Estimate the Water Content of Nonvascular Cryptogams

Communities of nonvascular cryptogams, such as mosses or lichens, are an important part of the Earth's biodiversity, contributing to theregulation of the carbon and nitrogen cycles in many ecosystems. Being poikilohydric organisms, they do not actively control their internal watercontent and need a humid environment to activate their metabolism. Therefore, studying water relationships of nonvascular cryptogams iscrucial to understand both their diversity patterns and their functions in the ecosystems. We present the BtM datalogger, a low-cost open-sourceplatform for the study of the water content of nonvascular cryptogams. The datalogger is designed to measure ambient temperature, humidity,and conductance from up to eight samples simultaneously. We provide a design for a printed circuit board (PCB), a detailed protocol to assemblethe components, and the required source code. All this makes the assembly of the BtM datalogger accessible to any research group, even tothose without previous specialized knowledge. Therefore, the design presented here has the potential to help popularize the use of this type ofdevice among ecologists and field biologists