Neuronal Networks Of The Mammalian Brain Have Functionally Different Classes Of Neurons: Suggestions For A Taxonomy Of Membrane Ionic Conductances

Deuterated Glutamate-Mediated Neuronal Activity on Micro-Electrode Arrays

Micromachines ◽

10.3390/mi11090830 ◽

2020 ◽

Vol 11 (9) ◽

pp. 830

Author(s):

Wataru Minoshima ◽

Kyoko Masui ◽

Tomomi Tani ◽

Yasunori Nawa ◽

Satoshi Fujita ◽

...

Keyword(s):

Spontaneous Activity ◽

Neuronal Activity ◽

Hippocampal Neurons ◽

Neuronal Networks ◽

Microelectrode Array ◽

Mammalian Brain ◽

Electrode Arrays ◽

Physiological Properties ◽

Micro Electrode Arrays

The excitatory synaptic transmission is mediated by glutamate (GLU) in neuronal networks of the mammalian brain. In addition to the synaptic GLU, extra-synaptic GLU is known to modulate the neuronal activity. In neuronal networks, GLU uptake is an important role of neurons and glial cells for lowering the concentration of extracellular GLU and to avoid the excitotoxicity. Monitoring the spatial distribution of intracellular GLU is important to study the uptake of GLU, but the approach has been hampered by the absence of appropriate GLU analogs that report the localization of GLU. Deuterium-labeled glutamate (GLU-D) is a promising tracer for monitoring the intracellular concentration of glutamate, but physiological properties of GLU-D have not been studied. Here we study the effects of extracellular GLU-D for the neuronal activity by using primary cultured rat hippocampal neurons that form neuronal networks on microelectrode array. The frequency of firing in the spontaneous activity of neurons increased with the increasing concentration of extracellular GLU-D. The frequency of synchronized burst activity in neurons increased similarly as we observed in the spontaneous activity. These changes of the neuronal activity with extracellular GLU-D were suppressed by antagonists of glutamate receptors. These results suggest that GLU-D can be used as an analog of GLU with equivalent effects for facilitating the neuronal activity. We anticipate GLU-D developing as a promising analog of GLU for studying the dynamics of glutamate during neuronal activity.

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Long-range temporal correlations in scale-free neuromorphic networks

Network Neuroscience ◽

10.1162/netn_a_00128 ◽

2020 ◽

Vol 4 (2) ◽

pp. 432-447 ◽

Cited By ~ 3

Author(s):

Shota Shirai ◽

Susant Kumar Acharya ◽

Saurabh Kumar Bose ◽

Joshua Brian Mallinson ◽

Edoardo Galli ◽

...

Keyword(s):

Long Range ◽

Neuronal Networks ◽

Temporal Dynamics ◽

Structural Characteristics ◽

Small World ◽

Mammalian Brain ◽

Scale Free ◽

Temporal Correlations ◽

Significant Step ◽

Computational Ability

Biological neuronal networks are the computing engines of the mammalian brain. These networks exhibit structural characteristics such as hierarchical architectures, small-world attributes, and scale-free topologies, providing the basis for the emergence of rich temporal characteristics such as scale-free dynamics and long-range temporal correlations. Devices that have both the topological and the temporal features of a neuronal network would be a significant step toward constructing a neuromorphic system that can emulate the computational ability and energy efficiency of the human brain. Here we use numerical simulations to show that percolating networks of nanoparticles exhibit structural properties that are reminiscent of biological neuronal networks, and then show experimentally that stimulation of percolating networks by an external voltage stimulus produces temporal dynamics that are self-similar, follow power-law scaling, and exhibit long-range temporal correlations. These results are expected to have important implications for the development of neuromorphic devices, especially for those based on the concept of reservoir computing.

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The effect of pulse width on the dynamics of pulse-coupled oscillators

10.1101/2021.02.06.430000 ◽

2021 ◽

Author(s):

Afifurrahman ◽

Ekkehard Ullner ◽

Antonio Politi

Keyword(s):

Pulse Width ◽

Neuronal Networks ◽

Finite Size ◽

Network Size ◽

Finite Size Effect ◽

Mammalian Brain ◽

Finite Width ◽

Numerical Studies ◽

First Order Phase Transition ◽

First Order Phase

Neuronal networks with a nearly balanced excitatory/inhibitory activity evoke significant interest in neuroscience due to the resulting emergence of strong fluctuations akin to those observed in the resting state of the mammalian brain. While most studies are limited to a δ-like pulse setup, much less is known about the collective behavior in the presence of finite pulse-widths. In this paper, we investigate exponential pulses, with the goal of testing the robustness of previously identified regimes such as the spontaneous emergence of collective irregular dynamics (CID). Moreover, the finite-width assumption paves the way to the investigation of a new ingredient, present in real neuronal networks: the asymmetry between excitatory and inhibitory pulses. Our numerical studies confirm the emergence of CID also in the presence of finite pulse-width, although with a couple of warnings: (i) the amplitude of the collective fluctuations decreases significantly when the pulse-width is comparable to the interspike interval; (ii) CID collapses onto a fully synchronous regime when the inhibitory pulses are sufficient longer than the excitatory ones. Both restrictions are compatible with the recorded behavior of real neurons. Additionally, we find that a seemingly first-order phase transition to a (quasi)-synchronous regime disappears in the presence of a finite width, confirming the peculiarity of the δ-spikes. A tran-sition to synchrony is instead observed upon increasing the ratio between the width of inhibitory and excitatory pulses: this transition is accompanied by a hysteretic region, which shrinks upon increasing the network size. Interestingly, for a connectivity comparable to that of the mammalian brain, such a finite-size effect is still sizable. Our numerical studies might help to understand abnormal synchronisation in neurological disorders.

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