Two simple yet biologically realistic models of synapses to be used in neuronal networks.
Item
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Title
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Two simple yet biologically realistic models of synapses to be used in neuronal networks.
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Identifier
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AAI9630501
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identifier
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9630501
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Creator
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Salcedo, Michaelangelo.
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Contributor
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Adviser: Thomas C. Wesselkamper
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Date
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1996
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Language
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English
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Publisher
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City University of New York.
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Subject
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Computer Science | Biology, Neuroscience
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Abstract
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The connections between neurons where information is processed, transformed, and communicated is at the synapse. A common paradigm in Computer Science for the connection is a link between the two neurons, where the influence of the first neuron to the second is determined by an arbitrary weight, generally assigned by the implementor. A more biologically realistic paradigm is proposed and implemented. A single neuron may have thousands of synapses with other neurons, and several with another neuron. The connection is dynamic, based on the prior activity of the synapse, and the impact of the action potential invading the presynaptic terminal at the time. Two examples of synapses are studied, one at the giant synapse of the Loligo pealii, which is a neuromuscular junction, and the other is the Schaffer collateral/CA1 synapse of the Hippocampus, a central synapse, of a rodent. Experimental data is reviewed for these synapses, and the basic primitives responsible for communication at the synapse, their functions and relationships, are identified from the research to build models that are easily implemented and computed, yet are biologically realistic, though not as detailed as those proposed by neuroscientists. State diagrams are given for both synapses, as well as the equations and relations necessary for their implementation.;The model of the Schaffer collateral/CA1 synapse is implemented in Qbasic, and data for a run of 5000 milliseconds is presented. The model demonstrated the feasibility of easy implementation. It is not as detailed as a model implemented by a neuroscientist, but maintains the primitive mechanisms responsible for dynamic communication and modulation over time at the synapse. The primitives and their relationships are listed and implemented in the Qbasic program. The data generated by the program is included and commented on. The data shows that the synapse responds according to the expected behavior: depletion and replenishment of available vesicular pool, failure of release, though invaded by action potential, multiquantal release, refractory periods, synaptic enhancement. This model offers a template that may serve to implement other types of central synapses that are based on the same kind of primitives, by adjusting the variables between the functions according to experimental data for a synapse under consideration. The next step in this research would be the expansion of synaptic enhancement to include PostTetanic Potentiation, and Long-Term Potentiation.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
