Modèle de Hodgkin–Huxley | EPFL Graph Search

droite|vignette|350x350px| Composants de base des modèles de type Hodgkin-Huxley. Les modèles de type Hodgkin-Huxley représentent la caractéristique biophysique des membranes cellulaires. La bicouche lipidique est représentée par une capacité (C m). Les canaux ioniques voltage-dépendants et de fuite sont représentés par des conductances non linéaires (g n) et linéaires (g L), respectivement. Les gradients électrochimiques entraînant le flux d'ions sont représentés par des batteries (E), et les pompes et échangeurs d'ions sont représentés par des sources de courant (I p). Le modèle Hodgkin-Huxley est un modèle mathématique qui décrit comment les potentiels d'action des neurones sont initiés et propagés. Il s'agit d'un ensemble d'équations différentielles non linéaires qui se rapprochent des caractéristiques électriques de cellules excitables telles que les neurones ou les myocytes cardiaques. C'est un système dynamique en temps continu. Originellement le modèle fut décrit en 1952 par A

A Pipeline Based Approach for Experimental Neuroscience Data Management

Muhammad Asif Jan

The field of neuroscience is witnessing a huge influx of experimental data thanks to the improvements in the data acquisition tools and techniques. Most of this data is being collected by thousands of experimenters located in various institutions around the world. There is also a growing interest in using this experimental data for building biologically realistic computational models of the neuronal systems. One such project i.e. the Blue Brain Project is developing a bottom-up neuronal modeling and simulation framework using experimental data collected at laboratories worldwide. However, to use the experimental data effectively in computational neuroscience research, the data needs to be annotated with metadata such as details of the experimental protocols and conditions, animal subject used etc. Most of the platforms for experimental neuroscience data management operate under the assumption that the primary data has been validated, and properly annotated before it is uploaded to the system. Thus putting the responsibility of validating, and annotating the experimental data with the experimenter conducting the study. Consequently, most experimenters maintain their own data using ad-hoc systems with non-standard metadata schemes; and only upload the final set of data to the data management platform. As a result, the metadata is usually incomplete, and does not always comply with the requirements of the data management platform, negatively impacting the reusability of their data. The current thesis work explored the question of the experimental data management within the context of the Blue Brain Project, and designs a data management pipeline catering for the acquisition, annotation and validation of the experimental data and associated metadata, in order to ensure that the data is usable for the computational modeling purposes. The pipeline enforces a data review process whereby incoming experimental data was made to go through a series of steps, analogous to the scientific review process, systematically improving the quality of the experimental data and associated metadata.

EPFL2011

Consideration of the effect of the anesthesia in the thalamocortical assemblies

Martin Hasler, Borja Ibarz Gabardos, Kumiko Oshima

Despite intensive research efforts, the effects of anesthesia on brain physiology and function have not been satisfactorily explained yet. Nevertheless, from what has been discovered up to now, we can attribute the effect of the anesthetics to changes in calcium(Ca2+) channels and in Gamma-aminobutyric acid type A(GABAA) synaptic receptors. In this paper, we investigate through simulations the consequences of such changes in a Hodgkin-Huxley-based model of thalamocortical assemblies.

2007

Neuronal medium that supports basic synaptic functions and activity of human neurons in vitro

Cynthia Marchand

Human cell reprogramming technologies offer access to live human neurons from patients and provide a new alternative for modeling neurological disorders in vitro. Neural electrical activity is the essence of nervous system function in vivo. Therefore, we examined neuronal activity in media widely used to culture neurons. We found that classic basal media, as well as serum, impair action potential generation and synaptic communication. To overcome this problem, we designed a new neuronal medium (BrainPhys basal + serum-free supplements) in which we adjusted the concentrations of inorganic salts, neuroactive amino acids, and energetic substrates. We then tested that this medium adequately supports neuronal activity and survival of human neurons in culture. Long-term exposure to this physiological medium also improved the proportion of neurons that were synaptically active. The medium was designed to culture human neurons but also proved adequate for rodent neurons. The improvement in BrainPhys basal medium to support neurophysiological activity is an important step toward reducing the gap between brain physiological conditions in vivo and neuronal models in vitro.

Natl Acad Sciences2015

A Pipeline Based Approach for Experimental Neuroscience Data Management

Muhammad Asif Jan

EPFL2011