IEEE transactions on bio-medical engineering
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IEEE Trans Biomed Eng · Apr 2008
Analysis of cultured neuronal networks using intraburst firing characteristics.
It is an open question whether neuronal networks, cultured on multielectrode arrays, retain any capability to usefully process information (learning and memory). A necessary prerequisite for learning is that stimulation can induce lasting changes in the network. To observe these changes, one needs a method to describe the network in sufficient detail, while stable in normal circumstances. ⋯ The PPs reveal a stable spatiotemporal pattern of activity during bursts over a period of several hours, making them useful for plasticity and learning studies. We also show that PPs can be used to estimate conditional firing probabilities. Doing so, yields an approach in which network bursting behavior and functional connectivity can be studied.
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IEEE Trans Biomed Eng · Apr 2008
Robust unsupervised detection of action potentials with probabilistic models.
We develop a robust and fully unsupervised algorithm for the detection of action potentials from extracellularly recorded data. Using the continuous wavelet transform allied to probabilistic mixture models and Bayesian probability theory, the detection of action potentials is posed as a model selection problem. Our technique provides a robust performance over a wide range of simulated conditions, and compares favorably to selected supervised and unsupervised detection techniques.
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This paper presents a new algorithm for electrocardiogram (ECG) signal compression based on local extreme extraction, adaptive hysteretic filtering and Lempel-Ziv-Welch (LZW) coding. The algorithm has been verified using eight of the most frequent normal and pathological types of cardiac beats and an multi-layer perceptron (MLP) neural network trained with original cardiac patterns and tested with reconstructed ones. Aspects regarding the possibility of using the principal component analysis (PCA) to cardiac pattern classification have been investigated as well. A new compression measure called "quality score," which takes into account both the reconstruction errors and the compression ratio, is proposed.
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IEEE Trans Biomed Eng · Apr 2008
Numerical design of experiment for sensitivity analysis--application to skin burn injury prediction.
Temperature evolution and skin burn process resulting from a laser radiation exposure are investigated in this paper. Transient temperature in skin is numerically estimated using a 1-D multilayered model based on Penne's equation. The degree of burn injury is numerically evaluated by using an Arrhenius-type function. ⋯ Thus, a sensitivity analysis has been performed in order to evaluate the effect of each parameters inaccuracy on temperature estimation and on burn injuries prediction (according to several authors' characterization). Investigated parameters uncertainties that crucially invalidate the thermal model are as follows: epidermis and dermis volumetric heat, extinction coefficient, and skin thickness of the affected area. Considering the damage prediction, the activation energy is a key parameter for the validation of an efficient predictive tool.
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IEEE Trans Biomed Eng · Apr 2008
A mathematical model of respiratory and biothermal dynamics in brain hypothermia treatment.
Brain hypothermia treatment (BHT) requires proper mechanical ventilation and therapeutic cooling. The cooling strategy for BHT has been mainly discussed in the literature while little information is available on the respiratory management. We first developed a mathematical model that integrates the respiratory and biothermal dynamics to discuss the simultaneous managements of mechanical ventilation and therapeutic cooling. ⋯ Second, model-based simulation of the current respiratory management in BHT suggests reduction of minute ventilation in reference to cooled brain temperature to stabilize the states of blood and brain oxygenation. Lastly, the relationship between cooling temperature and minute ventilation is approximated by a linear first-order transfer function of static gain 0.61min(-1) degrees C(-1) and time constant 8.9 h, which is used to develop a feedforward control to tune the mechanical ventilator in concert with temperature regulation of the cooling blanket. Discussion of the model encourages further studies that provide direct evidence from clinical experiments.