742 research outputs found
Other Voices piece by Mitch Lansky of Wytopitlock, author of Beyond the Beaut
No full textOther Voices piece by Mitch Lansky of Wytopitlock, author of Beyond the Beauty Strip, on the Compact for Maine\u27s Forests. Lansky writes that it is okay to oppose the compact
Diffusion approximation and first–passage–time problem for a model neuron. III. A birth–and–death process approach
No full textA stochastic model for single neuron's activity is constructed as the continuous limit of a birth-and-death process in the presence of a reversal hyperpolarization potential. The resulting process is a one dimensional diffusion with linear drift and infinitesimal variance, somewhat different from that proposed by Lansky and Lanska in a previous paper. A detailed study is performed for both the discrete process and its continuous approximation. In particular, the neuronal firing time problem is discussed and the moments of the firing time are explicitly obtained. Use of a new computation method is then made to obtain the firing p.d.f.. The behaviour of mean, variance and coefficient of variation of the firing time and of its p.d.f. is analysed to pinpoint the role played by the parameters of the model. A mathematical description of the return process for this neuronal diffusion model is finally provided to obtain closed form expressions for the asymptotic moments and steady state p.d.f. of the neuron's membrane potential
News & Issues piece on a Feb. 13 fire that destroyed the home of Mitch Lansky
No full textNews & Issues piece on a Feb. 13 fire that destroyed the home of Mitch Lansky and Sue Szwed in rural Wytopitlock. Lansky is one of Maine\u27s best-known forest activists and author of Beyond the Beauty Strip: Saving What\u27s Left of Our Forests as well as innumerable newspaper and magazine articles
Diffusion models and neural activity
No full textNeuronal interspike intervals can be characterized in terms of the first-passage time probability density of stochastic diffusion processes under steady state and periodic stimulation. The Wiener and Ornstein–Uhlenbeck models, and models with multiplicative noise, can be used to elucidate neuronal activity
Diffusion models and neural activity
No full textNeuronal interspike intervals can be characterized in terms of the first-passage time probability density of stochastic diffusion processes under steady state and periodic stimulation. The Wiener and Ornstein–Uhlenbeck models, and models with multiplicative noise, can be used to elucidate neuronal activity
An outline of some one-dimensional diffusion neuronal models
No full textStochastic neuronal models with restricted hyperpolarization due to the existence of inhibitory reversal potential are presented. The study focuses on models of diffusion type far which the mathematical theory is the most developed one. The introduction of the inhibitory reversal potential into the models causes that the infinitesimal variance is no more constant. The role of parameters in the models is considered
An outline of some one-dimensional diffusion neuronal models
No full textStochastic neuronal models with restricted hyperpolarization due to the existence of inhibitory reversal potential are presented. The study focuses on models of diffusion type far which the mathematical theory is the most developed one. The introduction of the inhibitory reversal potential into the models causes that the infinitesimal variance is no more constant. The role of parameters in the models is considered
Estimating input parameters from intracellular recordings in the Feller neuronal model
No full textWe study the estimation of the input parameters in a Feller neuronal model from a trajectory of the membrane potential sampled at discrete times. These input parameters are identified with the drift and the infinitesimal variance of the underlying stochastic diffusion process with multiplicative noise. The state space of the process is restricted from below by an inaccessible boundary. Further, the model is characterized by the presence of an absorbing threshold, the first hitting of which determines the length of each trajectory and which constrains the state space from above. We compare, both in the presence and in the absence of the absorbing threshold, the efficiency of different known estimators. In addition, we propose an estimator for the drift term, which is proved to be more efficient than the others, at least in the explored range of the parameters. The presence of the threshold makes the estimates of the drift term biased, and two methods to correct it are proposed
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