scholarly journals Large-scale algorithmic search identifies stiff and sloppy dimensions in synaptic architectures consistent with murine neocortical wiring

2021 ◽  
Author(s):  
Tarek Jabri ◽  
Jason N MacLean
Keyword(s):  
Visual Cortex ◽  
Large Scale ◽  
Normal Range ◽  
Dynamical Regimes ◽  
Algorithmic Search ◽  
Short And Long Term ◽  
Mouse Visual Cortex ◽  
Parameter Values ◽  
Connectivity Parameter

Complex systems can be defined by "sloppy" dimensions, meaning that their behavior is unmodified by large changes to specific parameter combinations, and "stiff" dimensions whose changes result in considerable modifications. In the case of the neocortex, sloppiness in synaptic architectures would be crucial to allow for the maintenance of spiking dynamics in the normal range despite a diversity of inputs and both short- and long-term changes to connectivity. Using simulations on neural networks with spiking matched to murine visual cortex, we determined the stiff and sloppy parameters of synaptic architectures across three classes of input (brief, continuous, and cyclical). Large-scale algorithmically-generated connectivity parameter values revealed that specific combinations of excitatory and inhibitory connectivity are stiff and that all other architectural details are sloppy. Stiff dimensions are consistent across a range of different input classes with self-sustaining synaptic architectures occupying a smaller subspace as compared to the other input classes. We also find that experimentally estimated connectivity probabilities from mouse visual cortex are similarly stiff and sloppy when compared to the architectures that we identified algorithmically. This suggests that simple statistical descriptions of spiking dynamics are a sufficient and parsimonious description of neocortical activity when examining structure-function relationships at the mesoscopic scale. Moreover, this study provides further evidence of the importance of the interrelationship of excitatory and inhibitory connectivity to establish and maintain stable spiking dynamical regimes in neocortex.

scholarly journals A Novel Iron Chloride Red-Ox Concentration Flow Cell Battery (ICFB) Concept; Power and Electrode Optimization

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1109
Author(s):  
Robert Bock ◽  
Björn Kleinsteinberg ◽  
Bjørn Selnes-Volseth ◽  
Odne Stokke Burheim
Keyword(s):  
Energy Storage ◽  
Large Scale ◽  
Fossil Fuels ◽  
Flow Cell ◽  
Iron Chloride ◽  
Carbon Electrodes ◽  
Concentration Difference ◽  
Term Energy ◽  
Short And Long Term

For renewable energies to succeed in replacing fossil fuels, large-scale and affordable solutions are needed for short and long-term energy storage. A potentially inexpensive approach of storing large amounts of energy is through the use of a concentration flow cell that is based on cheap and abundant materials. Here, we propose to use aqueous iron chloride as a reacting solvent on carbon electrodes. We suggest to use it in a red-ox concentration flow cell with two compartments separated by a hydrocarbon-based membrane. In both compartments the red-ox couple of iron II and III reacts, oxidation at the anode and reduction at the cathode. When charging, a concentration difference between the two species grows. When discharging, this concentration difference between iron II and iron III is used to drive the reaction. In this respect it is a concentration driven flow cell redox battery using iron chloride in both solutions. Here, we investigate material combinations, power, and concentration relations.

scholarly journals NMDAR-independent acetylcholine, serotonin, and norepinephrine mediated modulation of synaptic eligibility traces into LTD in mice visual cortex

2020 ◽  
Author(s):  
Shumsuzzaman Khan
Keyword(s):  
Visual Cortex ◽  
Ex Vivo ◽  
Brain Slices ◽  
Low Frequency ◽  
Decay Kinetics ◽  
Low Frequency Stimulation ◽  
Long Term Changes ◽  
Frequency Stimulation ◽  
Mouse Visual Cortex

AbstractIn reward-based learning, synaptic eligibility traces are a well-defined theoretical solution for the conversion of initial co-activation of pre and postsynaptic neurons into long-term changes in synaptic strength by reward-linked neuromodulators. However, the types of neuromodulators involved in such a phenomenon in mouse visual cortex remain unknown. To characterize the Ex vivo condition, we used optogenetic stimulation of channelrhodopsin-(ChR2) expressing Cre/Ai32(ChR2-eYFP); Tph2-Cre/Ai32(ChR2-eYFP); Thi-Cre/Ai32(ChR2-eYFP) homozygous mice, which release acetylcholine, serotonin, and norepinephrine, respectively. With these mice it is possible to measure the transformation of eligibility traces into long-term changes by endogenous neuromodulators. Here we delineated that layer 2/3 neurons in the visual cortex showed no LTD after conditioning with paired-pulse low-frequency stimulation (ppLFS; 2Hz, 15 min). However, if conditioning was paired with acetylcholine, serotonin, or norepinephrine release upon 473 nm optical stimulation in brain slices, LTD occurs in every case. Thus, our data suggests a new pathway to connect the gap between stimulus and reward. Moreover, we found that stimulation by theta-glass or metal stimulators evoked IPSC traces with the same amplitudes but differences in decay kinetics, further questioning the appropriate use of stimulators in brain slices for evoking an event.

scholarly journals Transient and localized optogenetic activation of somatostatin-interneurons in mouse visual cortex abolishes long-term cortical plasticity due to vision loss

2018 ◽  
Vol 223 (5) ◽  
pp. 2073-2095 ◽  
Author(s):  
Isabelle Scheyltjens ◽  
Samme Vreysen ◽  
Chris Van den Haute ◽  
Victor Sabanov ◽  
Detlef Balschun ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Vision Loss ◽  
Cortical Plasticity ◽  
Mouse Visual Cortex

scholarly journals Modelling large timescale and small timescale service variability

2019 ◽  
Vol 293 (1) ◽  
pp. 123-140
Author(s):  
Marco Gribaudo ◽  
Illés Horváth ◽  
Daniele Manini ◽  
Miklós Telek
Keyword(s):  
Service Time ◽  
Large Scale ◽  
Service Time Distribution ◽  
Efficient Computation ◽  
Short Term ◽  
Service Unit ◽  
Long Term Effect ◽  
Short And Long Term ◽  
Short Term Variability

Abstract The performance of service units may depend on various randomly changing environmental effects. It is quite often the case that these effects vary on different timescales. In this paper, we consider small and large scale (short and long term) service variability, where the short term variability affects the instantaneous service speed of the service unit and a modulating background Markov chain characterizes the long term effect. The main modelling challenge in this work is that the considered small and long term variation results in randomness along different axes: short term variability along the time axis and long term variability along the work axis. We present a simulation approach and an explicit analytic formula for the service time distribution in the double transform domain that allows for the efficient computation of service time moments. Finally, we compare the simulation results with analytic ones.

scholarly journals A short and sudden increase of the magnetic field strength and the accompanying spectral variability in the O9.7 V star HD 54879

2019 ◽  
Vol 484 (4) ◽  
pp. 4495-4506 ◽  
Author(s):  
S Hubrig ◽  
M Küker ◽  
S P Järvinen ◽  
A F Kholtygin ◽  
M Schöller ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Longitudinal Magnetic Field ◽  
Sudden Increase ◽  
Spectral Variability ◽  
Dipole Strength ◽  
Large Program ◽  
Short And Long Term ◽  
The Magnetic Field

Abstract Only 11 O-type stars have been confirmed to possess large-scale organized magnetic fields. The presence of a −600 G longitudinal magnetic field in the O9.7 V star HD 54879 with a lower limit of the dipole strength of ∼2 kG was discovered a few years ago in the framework of the ESO large program ‘B-fields in OB stars’. Our FORS 2 spectropolarimetric observations from 2017 October 4 to 2018 February 21 reveal the presence of short- and long-term spectral variability and a gradual magnetic field decrease from about −300 G down to about −90 G. Different scenarios are discussed in an attempt to interpret our observations. Our FORS 2 radial velocity measurements indicate that HD 54879 is a member of a long-period binary.

scholarly journals Short- and Long-Term Effects of Nonconsciously Processed Ambient Scents in a Servicescape: Findings From Two Field Experiments

2019 ◽  
Vol 22 (4) ◽  
pp. 440-455 ◽  
Author(s):  
Anna Girard ◽  
Marcel Lichters ◽  
Marko Sarstedt ◽  
Dipayan Biswas
Keyword(s):  
Large Scale ◽  
Field Experiments ◽  
Field Studies ◽  
Long Term Effects ◽  
Short Term ◽  
Railway Company ◽  
Short And Long Term ◽  
Ambient Scents ◽  
Short Term Effects

Ambient scents are being increasingly used in different service environments. While there is emerging research on the effects of scents, almost nothing is known about the long-term effects of consumers’ repeated exposure to ambient scents in a service environment as prior studies on ambient scents have been lab or field studies examining short-term effects of scent exposure only. Addressing this limitation, we examine the short- and long-term effects of ambient scents. Specifically, we present a conceptual framework for the short- and long-term effects of nonconsciously processed ambient scent in olfactory-rich servicescapes. We empirically test this framework with the help of two large-scale field experiments, conducted in collaboration with a major German railway company, in which consumers were exposed to a pleasant, nonconsciously processed scent. The first experiment demonstrates ambient scent’s positive short-term effects on consumers’ service perceptions. The second experiment—a longitudinal study conducted over a 4-month period—examines scent’s long-term effects on consumers’ reactions and demonstrates that the effects persist even when the scent has been removed from the servicescape.

scholarly journals Reciprocal Homosynaptic and Heterosynaptic Long-Term Plasticity of Corticogeniculate Projection Neurons in Layer VI of the Mouse Visual Cortex

2013 ◽  
Vol 33 (18) ◽  
pp. 7787-7798 ◽  
Author(s):  
M. K. Arami ◽  
K. Sohya ◽  
A. Sarihi ◽  
B. Jiang ◽  
Y. Yanagawa ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Projection Neurons ◽  
Mouse Visual Cortex ◽  
Layer Vi

scholarly journals Dalkurd FF

2020 ◽  
Vol 29 (supl) ◽  
pp. 105-113
Author(s):  
Tiago Duarte Dias
Keyword(s):  
Large Scale ◽  
First Year ◽  
Football Club ◽  
Local Institution ◽  
Long Term Changes ◽  
Short And Long Term ◽  
The City ◽  
Do So

As the whole world struggles with the appearance of a large-scale pandemic, individuals and institutions begin to cope with the perspective of both short and long-term changes to their plans. What had been planned out by many during January and February of 2020, no longer became feasible already during the following months. Thus, with the impossibility of knowing for how long this situation will persist, both individuals and institutions have changed their plans with a focus on when the situation will reverse to a degree of normalcy. This article aims to briefly understand and analyses the strategies centered around a Swedish football club founded by Kurdish individuals regarded to the consequences of the coronavirus crisis in the country. Both fans and employees at the club have changed their strategies regarding the first year they would be playing in their new hometown of Uppsala. The author will argue that, although, the crisis has changed their strategy and hampered their plans of becoming a local institution, it has not, in fact, changed their plans to be an integrated part of the city, but it has provided the club with newer opportunities to do so.

scholarly journals mGluR5-dependent acetylcholine, serotonin, and norepinephrine mediated modulation of synaptic eligibility traces into LTD in mice visual cortex

2021 ◽  
Author(s):  
Shumsuzzaman Khan
Keyword(s):  
Visual Cortex ◽  
Ex Vivo ◽  
Brain Slices ◽  
Low Frequency ◽  
Decay Kinetics ◽  
Low Frequency Stimulation ◽  
Long Term Changes ◽  
Frequency Stimulation ◽  
Mouse Visual Cortex

Abstract In reward-based learning, synaptic eligibility traces are a well-defined theoretical solution for the conversion of initial co-activation of pre and postsynaptic neurons into long-term changes in synaptic strength by reward-linked neuromodulators. However, the types of neuromodulators involved in such a phenomenon in mouse visual cortex remain unknown. To characterize the Ex vivo condition, we used optogenetic stimulation of channelrhodopsin-(ChR2) expressing Cre/Ai32(ChR2-eYFP); Tph2-Cre/Ai32(ChR2-eYFP); Thi-Cre/Ai32(ChR2-eYFP) homozygous mice, which release acetylcholine, serotonin, and norepinephrine, respectively. With these mice it is possible to measure the transformation of eligibility traces into long-term changes by endogenous neuromodulators. Here we delineated that layer 2/3 neurons in the visual cortex showed no LTD after conditioning with paired-pulse low-frequency stimulation (ppLFS; 2Hz, 15 min). However, if conditioning was paired with acetylcholine, serotonin, or norepinephrine release upon 473 nm optical stimulation in brain slices, LTD occurs in every case. Thus, our data suggests a new pathway to connect the gap between stimulus and reward. Moreover, we found that stimulation by theta-glass or metal stimulators evoked IPSC traces with the same amplitudes but differences in decay kinetics, further questioning the appropriate use of stimulators in brain slices for evoking an event.

scholarly journals A Scalable and Modular Automated Pipeline for Stitching of Large Electron Microscopy Datasets

2021 ◽  
Author(s):  
Gayathri Mahalingam ◽  
Russel Torres ◽  
Daniel Kapner ◽  
Eric T Trautman ◽  
Tim Fliss ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visual Cortex ◽  
High Throughput ◽  
Serial Section ◽  
Large Scale ◽  
Software Pipeline ◽  
Array Tomography ◽  
Automated Quality Control ◽  
Mouse Visual Cortex ◽  
The Brain

Serial section Electron Microscopy can produce high throughput imaging of large biological specimen volumes. The high-resolution images are necessary to reconstruct dense neural wiring diagrams in the brain, so called connectomes. A high fidelity volume assembly is required to correctly reconstruct neural anatomy and synaptic connections. It involves seamless 2D stitching of the images within a serial section followed by 3D alignment of the stitched sections. The high throughput of ssEM necessitates 2D stitching to be done at the pace of imaging, which currently produces tens of terabytes per day. To achieve this, we present a modular volume assembly software pipeline ASAP(Assembly Stitching and Alignment Pipeline) that is scalable and parallelized to work with distributed systems. The pipeline is built on top of the Render [18] services used in the volume assembly of the brain of adult Drosophila melanogaster [2]. It achieves high throughput by operating on the meta-data and transformations of each image stored in a database, thus eliminating the need to render intermediate output. The modularity of ASAP allows for easy adaptation to new algorithms without significant changes to the workflow. The software pipeline includes a complete set of tools to do stitching, automated quality control, 3D section alignment, and rendering of the assembled volume to disk. We also implemented a workflow engine that executes the volume assembly workflow in an automated fashion triggered following the transfer of raw data. ASAP has been successfully utilized for continuous processing of several large-scale datasets of the mouse visual cortex and human brain samples including one cubic millimeter of mouse visual cortex [1, 25]. The pipeline also has multi-channel processing capabilities and can be applied to fluorescence and multi-modal datasets like array tomography.

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