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Synaptic transmission as a cooperative phenomenon in confined systems
In this review paper, the theory of synaptic transmission (ST) was developed
and discussed. We used the hypothesis of isomorphism between: (a) the
cooperative behavior of mediators --- acetylcholine molecules (ACh) and
cholinoreceptors in a synaptic cleft with binding into mediator-receptor (AChR)
complexes, (b) the critical phenomena in confined binary liquid mixtures. The
systems of two (or three) nonlinear differential equations were proposed to
find the change of concentrations of ACh, AChR complexes, and ferment
acetylcholinesterase. The main findings of our study: the linear size of the
activation zone was evaluated; the process of postsynaptic membrane activation
was described as a cooperative process; different approximations of ACh
synchronous release were examined; stationary states and types of singular
points were studied for the proposed models of ST; the nonlinear kinetic model
with three order parameters demonstrated a strange-attractor behavior.Comment: 12 pages, 1 figur
The Evolution of Reaction-diffusion Controllers for Minimally Cognitive Agents
No description supplie
Mammalian Brain As a Network of Networks
Acknowledgements AZ, SG and AL acknowledge support from the Russian Science Foundation (16-12-00077). Authors thank T. Kuznetsova for Fig. 6.Peer reviewedPublisher PD
Modeling co-operative volume signaling in a plexus of nitric oxide synthase-expressing neurons
In vertebrate and invertebrate brains, nitric oxide (NO) synthase (NOS) is frequently expressed in extensive meshworks (plexuses) of exceedingly fine fibers. In this paper, we investigate the functional implications of this morphology by modeling NO diffusion in fiber systems of varying fineness and dispersal. Because size severely limits the signaling ability of an NO-producing fiber, the predominance of fine fibers seems paradoxical. Our modeling reveals, however, that cooperation between many fibers of low individual efficacy can generate an extensive and strong volume signal. Importantly, the signal produced by such a system of cooperating dispersed fibers is significantly more homogeneous in both space and time than that produced by fewer larger sources. Signals generated by plexuses of fine fibers are also better centered on the active region and less dependent on their particular branching morphology. We conclude that an ultrafine plexus is configured to target a volume of the brain with a homogeneous volume signal. Moreover, by translating only persistent regional activity into an effective NO volume signal, dispersed sources integrate neural activity over both space and time. In the mammalian cerebral cortex, for example, the NOS plexus would preferentially translate persistent regional increases in neural activity into a signal that targets blood vessels residing in the same region of the cortex, resulting in an increased regional blood flow. We propose that the fineness-dependent properties of volume signals may in part account for the presence of similar NOS plexus morphologies in distantly related animals
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