A new approach to the spatio-temporal pattern identification in neuronal multi-electrode registrations

A lot of methods were created in last decade for the spatio-temporal analysis of multi-electrode array (MEA) neuronal data sets. All these methods were implemented starting from a channel to channel analysis, with a great computational effort and onerous spatial pattern recognition task. 
Our idea is to approach the MEA data collection from a different point of view, i.e. considering all channels simultaneously. We transform the 2D plus time MEA signal in a mono-dimensional plus time signal and elaborate it as a normal 1D signal, using the Space-Amplitude Transform method. 
This geometrical transformation is completely invertible and allows to employ very fast processing algorithms. 
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A NEW APPROACH TO THE SPATIO-TEMPORAL PATTERN IDENTIFICATION IN NEURONAL MULTI-ELECTRODE REGISTRATIONS

A lot of methods were created in last decade for the spatio-temporal analysis of multi-electrode array (MEA) neuronal data sets. All these methods were implemented starting from a channel to channel analysis, with a great computational effort and onerous spatial pattern recognition task. Our idea is to approach the MEA data collection from a different point of view, i.e. considering all channels simultaneously. We transform the 2D plus time MEA signal in a mono-dimensional plus time signal and elaborate it as a normal 1D signal, using the Space-Amplitude Transform method. This geometrical transformation is completely invertible and allows to employ very fast processing algorithms

The FPGA based trigger and data acquisition system for the CERN NA62 experiment

The main goal of the NA62 experiment at CERN is to measure the branching ratio of the ultra-rare K+ → π+vv decay, collecting about 100 events to test the Standard Model of Particle Physics. Readout uniformity of sub-detectors, scalability, efficient online selection and lossless high rate readout are key issues. The TDCB and TEL62 boards are the common blocks of the NA62 TDAQ system. TDCBs measure hit times from sub-detectors, TEL62s process and store them in a buffer, extracting only those requested by the trigger system following the matching of trigger primitives produced inside TEL62s themselves. During the NA62 Technical Run at the end of 2012 the TALK board has been used as prototype version of the L0 Trigger Processor

A high-resolution TDC-based board for a fully digital trigger and data acquisition system in the NA62 experiment at CERN

A Time to Digital Converter (TDC) based system, to be used for most sub-detectors in the high-flux rare-decay experiment NA62 at CERN SPS, was built as part of the NA62 fully digital Trigger and Data AcQuisition system (TDAQ), in which the TDC Board (TDCB) and a general-purpose motherboard (TEL62) will play a fundamental role. While TDCBs, housing four High Performance Time to Digital Converters (HPTDC), measure hit times from sub-detectors, the motherboard processes and stores them in a buffer, produces trigger primitives from different detectors and extracts only data related to the lowest trigger level decision, once this is taken on the basis of the trigger primitives themselves. The features of the TDCB board developed by the Pisa NA62 group are extensively discussed and performance data is presented in order to show its compliance with the experiment requirements.Comment: 6 pages, 7 figures, presented to IEEE RT 2014 Conference and I want to publish in TN

Modular sito-specific grassing as an agroecological strategy in viticultural systems

Currently, agriculture is strongly dependent on the availability of fossil fuels, other external inputs and natural resources contributing about one fifth to the global emission of greenhouse gases into the atmosphere. There are, however, ample opportunities to mitigate the impact of agricultural activities on the climate. By appropriate soil management, organic and biodynamic woody systems can become quantitatively important sites for the provision of ecosystem services (protection of water, soil, biodiversity and landscape, carbon sequestration and efficient use of water resources), able to actively counteract climate change. The agroecological system developed proposed by the "AgroEcology Participatory Research Group\u201d (University of Bologna), introduce, among the innovative and highly sustainable techniques of soil management, the "stripped" biodiverse grassing, already successfully adopted in Italy and abroad. The system consists in the cultivation, along the row, of legumes and grasses with low water requirements, some of which are self-reseeding (eg. subterranean clover, burclover) and of a mixture of herbaceous species (eg. French honeysuckle, field beans, barley) in the alley. Noteworthy, the inclusion of these species, particularly of self-reseeding legumes, does not imply additional water consumption during the summer period. The soil protection provided by herbaceous species after cutting (or rolling) in the alleys and by self-reseeding legumes in the row, reduce soil evaporation and organic matter oxidation phenomena. Field trials conducted in different Italian farms have demonstrated the multiple benefits of the modular sito-specific grassing enhancing carbon sequestration, biodiversity, resilience and productivity of the viticultural systems

A pre-docking source for the power-law behavior of spontaneous quantal release: application to the analysis of LTP

In neurons, power-law behavior with different scaling exponents has been reported at many different levels, including fluctuations in membrane potentials, synaptic transmission up to neuronal network dynamics. Unfortunately in most cases the source of this nonlinear feature remains controversial. Here we have analyzed the dynamics of spontaneous quantal release at hippocampal synapses and characterized their power-law behavior. While in control conditions a fractal exponent greater than zero was rarely observed, its value was greatly increased by α-latrotoxin (α-LTX), a potent stimulator of spontaneous release, known to act at the very last step of vesicle fusion. Based on computer modeling, we confirmed that at an increase in fusion probability would unmask a pre-docking phenomenon with 1/f structure, where α estimated from the release series appears to sense the increase in release probability independently from the number of active sites. In the simplest scenario the pre-docking 1/f process could coincide with the Brownian diffusion of synaptic vesicles. Interestingly, when the effect of long-term potentiation (LTP) was tested, a ∼200% long-lasting increase in quantal frequency was accompanied by a significant increase in the scaling exponent. The similarity between the action of LTP and of α-LTX suggests an increased contribution of high release probability sites following the induction of LTP. In conclusion, our results indicate that the source of the synaptic powerlaw behavior arises before synaptic vesicles dock to the active zone and that the fractal exponent α is capable of sensing a change in release probability independently from the number of active sites or synapses. © 2015 Lamanna, Signorini, Cerutti and Malgaroli

Nanotopography and microconfinement impact on primary hippocampal astrocyte morphology, cytoskeleton and spontaneous calcium wave signalling

Astrocytes' organisation affects the functioning and the fine morphology of the brain, both in physiological and pathological contexts. Although many aspects of their role have been characterised, their complex functions remain, to a certain extent, unclear with respect to their contribution to brain cell communication. Here, we studied the effects of nanotopography and microconfinement on primary hippocampal rat astrocytes. For this purpose, we fabricated nanostructured zirconia surfaces as homogenous substrates and as micrometric patterns, the latter produced by a combination of an additive nanofabrication and micropatterning technique. These engineered substrates reproduce both nanotopographical features and microscale geometries that astrocytes encounter in their natural environment, such as basement membrane topography, as well as blood vessels and axonal fibre topology. The impact of restrictive adhesion manifests in the modulation of several cellular properties of single cells (morphological and actin cytoskeletal changes) and the network organisation and functioning. Calcium wave signalling was observed only in astrocytes grown in confined geometries, with an activity enhancement in cells forming elongated agglomerates with dimensions typical of blood vessels or axon fibres. Our results suggest that calcium oscillation and wave propagation are closely related to astrocytic morphology and actin cytoskeleton organisation

Scale invariant disordered nanotopography promotes hippocampal neuron development and maturation with involvement of mechanotransductive pathways

The identification of biomaterials which promote neuronal maturation up to the generation of integrated neural circuits is fundamental for modern neuroscience. The development of neural circuits arises from complex maturative processes regulated by poorly understood signaling events,often guided by the extracellular matrix (ECM). Here we report that nanostructured zirconia surfaces,produced by supersonic cluster beam deposition of zirconia nanoparticles and characterized by ECM-like nanotopographical features,can direct the maturation of neural networks. Hippocampal neurons cultured on such cluster-assembled surfaces displayed enhanced differentiation paralleled by functional changes. The latter was demonstrated by single-cell electrophysiology showing earlier action potential generation and increased spontaneous postsynaptic currents compared to the neurons grown on the featureless unnaturally flat standard control surfaces. Label-free shotgun proteomics broadly confirmed the functional changes and suggests furthermore a vast impact of the neuron/nanotopography interaction on mechanotransductive machinery components,known to control physiological in vivo ECM-regulated axon guidance and synaptic plasticity. Our results indicate a potential of cluster-assembled zirconia nanotopography exploitable for the creation of efficient neural tissue interfaces and cell culture devices promoting neurogenic events,but also for unveiling mechanotransductive aspects of neuronal development and maturation

Micropatterning of substrates for the culture of cell networks by stencil-assisted additive nanofabrication

The fabrication of in vitro neuronal cell networks where cells are chemically or electrically connected to form functional circuits with useful properties is of great interest. Standard cell culture substrates provide ensembles of cells that scarcely reproduce physiological structures since their spatial organization and connectivity cannot be controlled. Supersonic Cluster Beam Deposition (SCBD) has been used as an effective additive method for the large-scale fabrication of interfaces with extracellular matrix-mimicking surface nanotopography and reproducible morphological properties for cell culture. Due to the high collimation of SCBD, it is possible to exploit stencil masks for the fabrication of patterned films and reproduce features as small as tens of micrometers. Here, we present a protocol to fabricate micropatterned cell culture substrates based on the deposition of nanostructured cluster-assembled zirconia films by stencil-assisted SCBD. The effectiveness of this approach is demonstrated by the fabrication of micrometric patterns able to confine primary astrocytes. Calcium waves propagating in the astrocyte networks are shown