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Primeur weekly 2020-09-14

Focus

Some RISC-V high performance implementations presented at RISC-V Global Forum by European Processor Initiative, NSITEXE, OpenBLAS, and SemiDynamics ...

Exascale supercomputing

Combustion pioneer named Department of Energy fellow ...

Quantum computing

New method prevents quantum computers from crashing ...

Q-CTRL and Quantum Machines announce partnership to accelerate quantum computing development ...

Cambridge Quantum Computing welcomes Mehdi Bozzo-Rey ...

Focus on Europe

Researchers develop molecule to store solar energy ...

First release of PROCESS software now available ...

From artificial intelligence to nanomaterials and astrophysics - Seven Irish research projects to benefit from EuroHPC Academic Flagship Programme ...

Middleware

SDSC to help create science gateway for new materials discovery ...

Hardware

NCSA's Donna J. Cox honoured with rare IPS Technology Innovation Award ...

Advanced NVMe controller technology for next generation memory devices ...

Credo announces the DOVE platform, its second generation of low power PAM4 DSPs for 100G/200G/400G data networks ...

Tachyum opens U.S., EU and NATO Government Business Unit ...

National Science Foundation awards CENIC an international networking grant for operation of Pacific Wave ...

UCF Consortium receives open source contribution from Arm to speed access to persistent memory storage ...

Liqid announces agreement with Arrow Electronics to bring composable disaggregated infrastructure solutions to data centres worldwide ...

Research and Markets to issue Global Hybrid Memory Cube (HMC) and High-Bandwidth Memory (HBM) Suppliers Strategic Positioning and Leadership Quadrant Report 2020 ...

Genomics England scales up genomic sequencing with Quantum ActiveScale object storage ...

NVIDIA to acquire Arm for $40 billion, creating world's premier computing company for the age of AI ...

Applications

NCSA and University of Illinois announce new Center for AstroPhysical Surveys ...

Lead lab selected for next-generation cosmic microwave background experiment ...

Insilico announces the launch of AI-powered COVIDomic to support COVID-19 research worldwide ...

Model shows that the speed neurons fire impacts their ability to synchronize ...

Physicists achieve tunable spin wave excitation ...

EBRAINS makes bid to enter the European Research Infrastructure Roadmap with ten-country strong coalition and France as lead country ...

Mysterious cellular droplets come into focus ...

The presence of resonating cavities above sunspots has been confirmed ...

The Hospital Clínic and BSC will use artificial intelligence to predict the evolution of patients with COVID-19 ...

ORIGINS - answers to existential questions ...

Altair announces 2020 Global Technology Conference to explore "The Future of..." ...

The Cloud

National Science Foundation-funded CloudBank now operational ...

Schlumberger, IBM and Red Hat announce major hybrid Cloud collaboration for the energy industry ...

Red Hat Marketplace aims to accelerate open hybrid Cloud innovation with certified software solutions ready to run on any Cloud ...

Renesas introduces DDR5 data buffer for high-performance server and Cloud service applications ...

NETINT deploys video transcoding technology in the Nimbix Cloud ...

Model shows that the speed neurons fire impacts their ability to synchronize


Cell membranes have a voltage across them due to the uneven distribution of charged particles, called ions, between the inside and outside of the cell. Neurons can shuttle ions across their membrane through channels and pumps, which changes the voltage of the membrane. Fast firing Purkinje neurons have a higher membrane voltage than slow firing neurons. Credit: Image modified from: How neurons communicate, by OpenStax College, Biology (CC BY 4.0).
8 Sep 2020 Okinawa - Research conducted by the Computational Neuroscience Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) has shown for the first time that a computer model can replicate and explain a unique property displayed by a crucial brain cell. Their findings, published in eLife , shed light on how groups of neurons can self-organize by synchronizing when they fire fast.

The model focuses on Purkinje neurons, which are found within the cerebellum. This dense region of the hindbrain receives inputs from the body and other areas of the brain in order to fine-tune the accuracy and timing of movement, among other tasks.

"Purkinje cells are an attractive target for computational modeling as there has always been a lot of experimental data to draw from", stated Professor Erik De Schutter, who leads the Computation Neuroscience Unit. "But a few years ago, experimental research into these neurons uncovered a strange behavior that couldn't be replicated in any existing models."

These studies showed that the firing rate of a Purkinje neuron affected how it reacted to signals fired from other neighboring neurons.

The rate at which a neuron fires electrical signals is one of the most crucial means of transmitting information to other neurons. Spikes, or action potentials, follow an "all or nothing" principle - either they occur, or they don't - but the size of the electrical signal never changes, only the frequency. The stronger the input to a neuron, the quicker that neuron fires.

But neurons don't fire in an independent manner. "Neurons are connected and entangled with many other neurons that are also transmitting electrical signals. These spikes can perturb neighboring neurons through synaptic connections and alter their firing pattern", explained Prof. De Schutter.

Interestingly, when a Purkinje cell fires slowly, spikes from connected cells have little effect on the neuron's spiking. But, when the firing rate is high, the impact of input spikes grows and makes the Purkinje cell fire earlier.

"The existing models could not replicate this behaviour and therefore could not explain why this happened. Although the models were good at mimicking spikes, they lacked data about how the neurons acted in the intervals between spikes", Prof. De Schutter stated. "It was clear that a newer model including more data was needed."

Fortunately, Prof. De Schutter's unit had just finished developing an updated model, an immense task primarily undertaken by now former postdoctoral researcher, Dr. Yunliang Zang.

Once completed, the team found that for the first time, the new model was able to replicate the unique firing-rate dependent behaviour.

In the model, they saw that in the interval between spikes, the Purkinje neuron's membrane voltage in slowly firing neurons was much lower than the rapidly firing ones.

"In order to trigger a new spike, the membrane voltage has to be high enough to reach a threshold. When the neurons fire at a high rate, their higher membrane voltage makes it easier for perturbing inputs, which slightly increase the membrane voltage, to cross this threshold and cause a new spike", explained Prof. De Schutter.

The researchers found that these differences in the membrane voltage between fast and slow firing neurons were because of the specific types of potassium ion channels in Purkinje neurons.

"The previous models were developed with only the generic types of potassium channels that we knew about. But the new model is much more detailed and complex, including data about many Purkinje cell-specific types of potassium channels. So that's why this unique behavior could finally be replicated and understood", stated Prof. De Schutter.

The researchers then decided to use their model to explore the effects of this behaviour on a larger-scale, across a network of Purkinje neurons. They found that at high firing rates, the neurons started to loosely synchronize and fire together at the same time. Then when the firing rate slowed down, this coordination was quickly lost.

Using a simpler, mathematical model, Dr. Sungho Hong, a group leader in the unit, then confirmed this link was due to the difference in how fast and slow firing Purkinje neurons responded to spikes from connected neurons.

"This makes intuitive sense", stated Prof. De Schutter. He explained that for neurons to be able to sync up, they need to be able to adapt their firing rate in response to inputs to the cerebellum. "So this syncing with other spikes only occurs when Purkinje neurons are firing rapidly", he added.

The role of synchrony is still controversial in neuroscience, with its exact function remaining poorly understood. But many researchers believe that synchronization of neural activity plays a role in cognitive processes, allowing communication between distant regions of the brain. For Purkinje neurons, they allow strong and timely signals to be sent out, which experimental studies have suggested could be important for initiating movement.

"This is the first time that research has explored whether the rate at which neurons fire affects their ability to synchronize and explains how these assemblies of synchronized neurons quickly appear and disappear", stated Prof. De Schutter. "We may find that other circuits in the brain also rely on this rate-dependent mechanism."

The team now plans to continue using the model to probe deeper into how these brain cells function, both individually and as a network. And, as technology develops and computing power strengthens, Prof. De Schutter has an ultimate life ambition.

"My goal is to build the most complex and realistic model of a neuron possible", stated Prof. De Schutter. "OIST has the resources and computing power to do that, to carry out really fun science that pushes the boundary of what's possible. Only by delving into deeper and deeper detail in neurons, can we really start to better understand what's going on."

Source: Okinawa Institute of Science and Technology (OIST) Graduate University

Back to Table of contents

Primeur weekly 2020-09-14

Focus

Some RISC-V high performance implementations presented at RISC-V Global Forum by European Processor Initiative, NSITEXE, OpenBLAS, and SemiDynamics ...

Exascale supercomputing

Combustion pioneer named Department of Energy fellow ...

Quantum computing

New method prevents quantum computers from crashing ...

Q-CTRL and Quantum Machines announce partnership to accelerate quantum computing development ...

Cambridge Quantum Computing welcomes Mehdi Bozzo-Rey ...

Focus on Europe

Researchers develop molecule to store solar energy ...

First release of PROCESS software now available ...

From artificial intelligence to nanomaterials and astrophysics - Seven Irish research projects to benefit from EuroHPC Academic Flagship Programme ...

Middleware

SDSC to help create science gateway for new materials discovery ...

Hardware

NCSA's Donna J. Cox honoured with rare IPS Technology Innovation Award ...

Advanced NVMe controller technology for next generation memory devices ...

Credo announces the DOVE platform, its second generation of low power PAM4 DSPs for 100G/200G/400G data networks ...

Tachyum opens U.S., EU and NATO Government Business Unit ...

National Science Foundation awards CENIC an international networking grant for operation of Pacific Wave ...

UCF Consortium receives open source contribution from Arm to speed access to persistent memory storage ...

Liqid announces agreement with Arrow Electronics to bring composable disaggregated infrastructure solutions to data centres worldwide ...

Research and Markets to issue Global Hybrid Memory Cube (HMC) and High-Bandwidth Memory (HBM) Suppliers Strategic Positioning and Leadership Quadrant Report 2020 ...

Genomics England scales up genomic sequencing with Quantum ActiveScale object storage ...

NVIDIA to acquire Arm for $40 billion, creating world's premier computing company for the age of AI ...

Applications

NCSA and University of Illinois announce new Center for AstroPhysical Surveys ...

Lead lab selected for next-generation cosmic microwave background experiment ...

Insilico announces the launch of AI-powered COVIDomic to support COVID-19 research worldwide ...

Model shows that the speed neurons fire impacts their ability to synchronize ...

Physicists achieve tunable spin wave excitation ...

EBRAINS makes bid to enter the European Research Infrastructure Roadmap with ten-country strong coalition and France as lead country ...

Mysterious cellular droplets come into focus ...

The presence of resonating cavities above sunspots has been confirmed ...

The Hospital Clínic and BSC will use artificial intelligence to predict the evolution of patients with COVID-19 ...

ORIGINS - answers to existential questions ...

Altair announces 2020 Global Technology Conference to explore "The Future of..." ...

The Cloud

National Science Foundation-funded CloudBank now operational ...

Schlumberger, IBM and Red Hat announce major hybrid Cloud collaboration for the energy industry ...

Red Hat Marketplace aims to accelerate open hybrid Cloud innovation with certified software solutions ready to run on any Cloud ...

Renesas introduces DDR5 data buffer for high-performance server and Cloud service applications ...

NETINT deploys video transcoding technology in the Nimbix Cloud ...