Spelling suggestions: "subject:"neurons - amathematical models."" "subject:"neurons - dmathematical models.""
1 |
Bilinear system model of the action potential of a single neuronYahiaoui, Youcef 07 June 1999 (has links)
Neurons are characterized by an electric potential which is established between their inside
and outside media. They exhibit specific voltage fluctuations, in response to strong enough
current impulses, called action potentials.
In this work, a bang-bang controlled bilinear system (BLS) is derived to approximate
the generation of a simple neuron's action potential. The shape of the response, as well as
the timing seem to be useful for experimental planning and interpretation to neural physiologists.
The BLS-model has the potential to aid the design and fabrication of commercial
neural networks for communication, control and computing.
In this manner, a variable-structure membrane impedance, such as exhibited by a
stable focus and a saddle point in state space, and/or other modes, arises naturally. Added
positive and negative stimuli, such as from other neurons, have the capability to alter the
voltage across the inside and the outside media of the neuron and elicit an advanced or
delayed response in the action potential. Such latency is significant as noted above, and is
an active area of experimental research.
The response shape and the timing with respect to some other event(latency} are
related to experimental data. This simple model is compared to the complex and highly
celebrated Hodgkin-Huxley model for the squid giant axon. The bang-bang feedback control
is given a biological interpretation of sodium and potassium ion channels in this axon, that
yields a variable-structure membrane impedance. / Graduation date: 2000
|
2 |
Expert system in stochastic analysis of neuronal signals鄭嘉亨, Cheng, Ka-hang. January 1993 (has links)
published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
|
3 |
Exploring the feasibility of the detection of neuronal activity evoked by dendrite currents using MRIDolasinski, Brian D. 29 June 2011 (has links)
MRI has been applied to directly detecting neuronal activity. The direct detection of multiple dendrite sites within the brain offers an important tool in the analysis of the brain for mapping cognition. In this, multiple dendrite contributions can be applied with the same model between the parallel and anti-parallel orientations depending on a spatial depolarization and re-polarization wave. Once the strength of the dendritic contribution was calculated, the spatially dependent phase shifts were theoretically modeled. In the construction of this column the dendrites were modeled as having cylindrical symmetry, uniform current density, and the intracellular current was taken as the primary current contribution to the volume dendrite model.
The method examined the system using the known volume density of the dendrites treated with the current dipole model over a voxel. The maximum effect of the field strength, phase, and percent signal change was theoretically calculated. The maximum field was calculated as 1.07 nT, the maximum phase was calculated as 2.14 mrad, and the maximum percent signal increase was calculated as 0.217 %. / Overview of the basics of MRI imaging -- Overview of neural activation and imaging of the activation -- Theory and methods -- Results. / Department of Physics and Astronomy
|
4 |
Détection précoce de crises d'épilepsie à l'aide d'une modélisation du comportement oscillatoire neuronalHocepied, Gatien 17 September 2012 (has links)
Détection précoce de crises<p>d’épilepsie à l’aide d’une<p>modélisation du comportement<p>oscillatoire neuronal / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
|
5 |
Avaliação da estabilidade do sincronismo entre sistemas dinâmicos não-lineares : aspectos teóricos e aplicações / Analysis of the stability the synchronism between nonlinear dynamical systems : theoretical aspects and applicationsSantos, Odair Vieira dos, 1973- 26 February 2015 (has links)
Orientadores: Romis Ribeiro de Faissol Attux, Diogo Coutinho Soariano, Filipe Ieda Fazanaro / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-27T04:17:12Z (GMT). No. of bitstreams: 1
Santos_OdairVieirados_D.pdf: 3365036 bytes, checksum: 967476ee0acb26bf5197de95e344c6c9 (MD5)
Previous issue date: 2015 / Resumo: O problema de análise do sincronismo entre sistemas dinâmicos se reveste de enorme importância prática, uma vez que ocorre em uma miríade de contextos naturais e artificiais. Para avaliar a ocorrência desse fenômeno, é usual lançar mão dos expoentes de Lyapunov condicionados, que refletem, em sua definição, o acoplamento entre sistemas. Nesta tese, é proposto um novo método para cálculo desses expoentes, que pode ser extremamente útil quando há descontinuidades ou quando o cálculo da matriz jacobiana é proibitivo. Esse método tem por base o método das dinâmicas clonadas para estimação do espectro convencional de Lyapunov. A nova proposta é validada em diversos cenários, partindo de sistemas clássicos e chegando aos modelos neuronais de Hindmarsh-Rose e Hodgkin-Huxley. O estudo do sincronismo uni- e bidirecional desses modelos, aliás, constitui também uma contribuição original do trabalho / Abstract: The problem of analyzing synchronism between dynamical systems is of enormous practical significance, as this phenomenon arises in several natural and artificial domains. To characterize the occurrence of synchronism, it is usual to employ the conditioned Lyapunov exponents, which reflect, in their definition, the coupling between systems. In this thesis, a new method for calculating these exponents is proposed, which can be extremely useful in the presence of discontinuities or when to calculate the Jacobian matrix is prohibitive. This method is based on the cloned dynamics approach for estimating the conventional Lyapunov spectrum. The new proposal is validated in a number of scenarios, ranging from classical systems to the Hindmarsh-Rose and Hodgkin-Huxley neuron models. The study of the uniand bidirectional synchronism of these models are apropos also an original contribution of this work / Doutorado / Automação / Doutor em Engenharia Elétrica
|
Page generated in 0.0727 seconds