Increasing availability of comprehensive experimental datasets and of high-performance computing resources are driving rapid growth in scale, complexity, and biological realism of computational models in neuroscience. To support construction and simulation, as well as sharing of such large-scale models, a broadly applicable, flexible, and high-performance data format is necessary. To address this need, we have developed the Scalable Open Network Architecture TemplAte (SONATA) data format. It is designed for memory and computational efficiency and works across multiple platforms. The format represents neuronal circuits and simulation inputs and outputs via standardized files and provides much flexibility for adding new conventions or extensions. SONATA is used in multiple modeling and visualization tools, and we also provide reference Application Programming Interfaces and model examples to catalyze further adoption. SONATA format is free and open for the community to use and build upon with the goal of enabling efficient model building, sharing, and reproducibility.

The function of the neocortex is fundamentally determined by its repeating microcircuit motif, but also by its rich, hierarchical, interregional structure with a highly specific laminar architecture. The last decade has seen the emergence of extensive new data sets on anatomy and connectivity at the whole brain scale, providing promising new directions for studies of cortical function that take into account the inseparability of whole-brain and microcircuit architectures. Here, we present a data-driven computational model of the anatomy of non-barrel primary somatosensory cortex of juvenile rat, which integrates whole-brain scale data while providing cellular and subcellular specificity. This multiscale integration was achieved by building the morphologically detailed model of cortical circuitry embedded within a volumetric, digital brain atlas. The model consists of 4.2 million morphologically detailed neurons belonging to 60 different morphological types, placed in the nonbarrel subregions of the Paxinos and Watson atlas. They are connected by 13.2 billion synapses determined by axo-dendritic overlap, comprising local connectivity and long-range connectivity defined by topographic mappings between subregions and laminar axonal projection profiles, both parameterized by whole brain data sets. Additionally, we incorporated core- and matrix-type thalamocortical projection systems, associated with sensory and higher-order extrinsic inputs, respectively. An analysis of the modeled synaptic connectivity revealed a highly nonrandom topology with substantial structural differences but also synergy between local and long-range connectivity. Long-range connections featured a more divergent structure with a comparatively small group of neurons serving as hubs to distribute excitation to far away locations. Taken together with analyses at different spatial granularities, these results support the notion that local and interregional connectivity exist on a spectrum of scales, rather than as separate and distinct networks, as is commonly assumed. Finally, we predicted how the emergence of primary sensory cortical maps is constrained by the anatomy of thalamo-cortical projections. A subvolume of the model comprising 211,712 neurons in the front limb, jaw, and dysgranular zone has been made freely and openly available to the community.

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22Increasing availability of comprehensive experimental datasets and of high-performance 23 computing resources are driving rapid growth in scale, complexity, and biological realism of 24 computational models in neuroscience. To support construction and simulation, as well as 25 sharing of such large-scale models, a broadly applicable, flexible, and high-performance data 26 format is necessary. To address this need, we have developed the Scalable Open Network 27 Architecture TemplAte (SONATA) data format. It is designed for memory and computational 28 efficiency and works across multiple platforms. The format represents neuronal circuits and 29 simulation inputs and outputs via standardized files and provides much flexibility for adding new 30 conventions or extensions. SONATA is used in multiple modeling and visualization tools, and 31 we also provide reference Application Programming Interfaces and model examples to catalyze 32 further adoption. SONATA format is free and open for the community to use and build upon 33 with the goal of enabling efficient model building, sharing, and reproducibility.34 68 compute environments. Another is that existing formats describe either static models or 69 simulation outputs, but not both. And, for broad adoption of a modeling data format, it needs to 70 be flexible enough to represent a variety of model types (point neuron, biophysically detailed, 71 etc.) and compatible with more specialized formats (e.g., SWC for neuronal morphologies 72 (Cannon et al., 1998)), without compromising computational performance. 73 3 74

Recently the importance of clustering storage nodes across site boundaries is becoming more clear, thanks also to the recent ongoing initiatives in the CMS and ATLAS experiments. These approaches are supposed to promote simplicity in accessing the data and offering new possibilities for resilience and data placement strategies, that may also lead to a better utilization of the available CPU slots. Here we report on work that seeks to exploit the federation potential of redirectable protocols like HTTP/WebDAV and build a dynamic, scalable, persistency-free system that offers a unique view of the storage and metadata ensemble and the possibility of integration of other compatible resources such as those from cloud providers. The challenge, here undertaken by the providers of dCache and DPM, partially in the context of EMI-data, and pragmatically open to any other Grid and Cloud storage solutions, is to build such a system while being able to accommodate name translations from existing catalogues (e.g. LFCs), experiment-based metadata catalogues, or stateless algorithmic name translations, also known as "trivial file catalogues". Other technical challenges that will determine the success of this initiative include performance, latency and scalability, and the ability to create worldwide storage federations that are able to redirect clients to repositories that they can efficiently access, for instance trying to choose the endpoints that are closer or applying other criteria. One of the key requirements is to use standard clients (provided by OS'es or open source distributions, e.g. Web browsers) to access an already aggregated system. This was accomplished by exploiting the possibilities offered by the DMLite framework, in order to integrate with existing frontends like the Apache server. We believe that the features of a loosely coupled federation of open-protocols-based storage elements will open many possibilities of evolving the current computing models without disrupting them, and, at the same time, can operate with the existing infrastructures, follow their evolution path and add storage centers that can be acquired as a third-party service.