NeuroML is an XML (Extensible Markup Language) based model description language that aims to provide a common data format for defining and exchanging models in computational neuroscience. The focus of NeuroML is on models which are based on the biophysical and anatomical properties of real neurons. [1]
The idea of creating NeuroML as a language for describing neuroscience models was first introduced by Goddard et al. (2001) [2] following meetings in Edinburgh where initial templates for the language structures were discussed. This initial proposal was based on general purpose structures proposed by Gardner et al. (2001). [3] At that time, the concept of NeuroML was closely linked with the idea of developing a software architecture in which a base application loads a range of plug-in components to handle different aspects of a simulation problem. Neosim (2003) was developed based on this goal, and early NeuroML development was closely aligned to this approach. Along with creating Neosim, Howell and Cannon developed a software library, the NeuroML Development Kit (NDK), to simplify the process of serializing models in XML. The NeuroML Development Kit implemented a particular dialect of XML, including the "listOfXXX" structure, which also found its way into SBML (Systems Biology Markup Language), but did not define any particular structures at the model description level. Instead, developers of plug-ins for Neosim were free to invent their own structures and serialize them via the NDK, in the hope that some consensus would emerge around the most useful ones. In practice, few developers beyond the Edinburgh group developed or used such structures and the resulting XML was too application specific to gain wider adoption. The Neosim project ended in 2005.
Based on the ideas in Goddard et al. (2001) and discussions with the Edinburgh group, Sharon Crook began a collaborative effort to develop a language for describing neuronal morphologies in XML called MorphML. [3] From the beginning, the idea behind MorphML was to develop a format for describing morphological structures that would include all of the necessary components to serve as a common data format with the added advantages of XML. At the same time, Padraig Gleeson and Angus Silver were developing neuroConstruct [4] for generating neuronal simulations for the NEURON and GENESIS simulators. At that time, neuroConstruct utilized an internal simulator-independent representation for morphologies, channel and networks. It was agreed that these efforts should be merged under the banner of NeuroML, and the current structure of NeuroML was created. The schema was divided into levels (e.g. MorphML, ChannelML, and NetworkML) to allow different applications to support different part of the language. [5] Since 2006 the XML Schema files for this version of the standard have been available from the NeuroML development site.
The main aims of the NeuroML initiative are to:
NeuroML is focused on biophysical and anatomical detailed models, i.e. incorporating real neuronal morphologies and membrane conductances (conductance based models), and network models based on known anatomical connectivity. The NeuroML structure is composed of Levels, where each Level deals with a particular biophysical scale. The modular nature of the specifications makes them easier to develop, understand, and use since one can focus on one module at a time; however, the modules are designed to fit together seamlessly. There are currently three Levels of NeuroML defined:
Current schemas in readable form are available on the NeuroML specifications page.
A list of software packages which support all or part of NeuroML is available on the NeuroML website.
NeuroML is an international, free and open community effort.
The NeuroML Team implements the NeuroML specifications, maintains the website and the validator, organizes annual workshops and other events, and manages specific funding for coordinating the further development of NeuroML. Version 2.0 of the NeuroML language is being developed by the Specification Committees. NeuroML also participates in the International Neuroinformatics Coordinating Facility Program on Multiscale Modeling.
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Neuroscience is the scientific study of the nervous system, its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developmental biology, cytology, psychology, physics, computer science, chemistry, medicine, statistics, and mathematical modeling to understand the fundamental and emergent properties of neurons, glia and neural circuits. The understanding of the biological basis of learning, memory, behavior, perception, and consciousness has been described by Eric Kandel as the "epic challenge" of the biological sciences.
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Computational neuroscience is a branch of neuroscience which employs mathematics, computer science, theoretical analysis and abstractions of the brain to understand the principles that govern the development, structure, physiology and cognitive abilities of the nervous system.
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Neuromorphology is the study of nervous system form, shape, and structure. The study involves looking at a particular part of the nervous system from a molecular and cellular level and connecting it to a physiological and anatomical point of view. The field also explores the communications and interactions within and between each specialized section of the nervous system. Morphology is distinct from morphogenesis. Morphology is the study of the shape and structure of biological organisms, while morphogenesis is the study of the biological development of the shape and structure of organisms. Therefore, neuromorphology focuses on the specifics of the structure of the nervous system and not the process by which the structure was developed. Neuromorphology and morphogenesis, while two different entities, are nonetheless closely linked.
GENESIS is a simulation environment for constructing realistic models of neurobiological systems at many levels of scale including: sub-cellular processes, individual neurons, networks of neurons, and neuronal systems. These simulations are “computer-based implementations of models whose primary objective is to capture what is known of the anatomical structure and physiological characteristics of the neural system of interest”. GENESIS is intended to quantify the physical framework of the nervous system in a way that allows for easy understanding of the physical structure of the nerves in question. “At present only GENESIS allows parallelized modeling of single neurons and networks on multiple-instruction-multiple-data parallel computers.” Development of GENESIS software spread from its home at Caltech to labs at the University of Texas at San Antonio, the University of Antwerp, the National Centre for Biological Sciences in Bangalore, the University of Colorado, the Pittsburgh Supercomputing Center, the San Diego Supercomputer Center, and Emory University.
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The network of the human nervous system is composed of nodes that are connected by links. The connectivity may be viewed anatomically, functionally, or electrophysiologically. These are presented in several Wikipedia articles that include Connectionism, Biological neural network, Artificial neural network, Computational neuroscience, as well as in several books by Ascoli, G. A. (2002), Sterratt, D., Graham, B., Gillies, A., & Willshaw, D. (2011), Gerstner, W., & Kistler, W. (2002), and Rumelhart, J. L., McClelland, J. L., and PDP Research Group (1986) among others. The focus of this article is a comprehensive view of modeling a neural network. Once an approach based on the perspective and connectivity is chosen, the models are developed at microscopic, mesoscopic, or macroscopic (system) levels. Computational modeling refers to models that are developed using computing tools.
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