Leonel E Medina

Leonel E Medina
University of Santiago, Chile | USACH · Departamento de Ingeniería Informática

PhD

About

19
Publications
2,332
Reads
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221
Citations
Citations since 2016
8 Research Items
165 Citations
2016201720182019202020212022010203040
2016201720182019202020212022010203040
2016201720182019202020212022010203040
2016201720182019202020212022010203040
Additional affiliations
March 2018 - present
University of Santiago, Chile
Position
  • Professor (Assistant)
May 2017 - February 2018
Universidad de Valparaíso (Chile)
Position
  • PostDoc Position
August 2010 - present
Duke University
Position
  • Research Assistant

Publications

Publications (19)
Article
Full-text available
Objective: Incorporating high-frequency components in transcutaneous electrical stimulation (TES) waveforms may make it possible to stimulate deeper nerve fibers since the impedance of tissue declines with increasing frequency. However, the mechanisms of high-frequency TES remain largely unexplored. We investigated the properties of TES with frequ...
Article
Objective: Models of excitable cells consider the membrane specific capacitance as a ubiquitous and constant parameter. However, experimental measurements show that the membrane capacitance declines with increasing frequency, i.e., exhibits dispersion. We quantified the effects of frequency-dependent membrane capacitance, c(f), on the excitability...
Article
Full-text available
Background Incorporating kilohertz-frequency signals in transcutaneous electrical stimulation has been proposed as a means to overcome the impedance of the skin, thereby reaching deeper nerves. In particular, a transdermal amplitude modulated signal (TAMS), composed of a 210 kHz non-zero offset carrier modulated by rectangular pulses, was introduce...
Article
Significance Sensory neuroprostheses offer the promise of restoring perceptual function to people with impaired sensation. Here, we developed a paradigm using intracortical microstimulation (ICMS) for encoding the sensation of fingertip motion against texture. Monkeys learned to interpret time-varying ICMS patterns, evoked by the interplay of their...
Article
Full-text available
Alzheimer’s disease (AD) is one of the most significant health challenges of our time, affecting a growing number of the elderly population. In recent years, the retina has received increased attention as a candidate for AD biomarkers since it appears to manifest the pathological signatures of the disease. Therefore, its electrical activity may hin...
Preprint
Full-text available
The interferential current (IFC) therapy is a noninvasive electrical neurostimulation technique intended to activate deep neurons using surface electrodes. In IFC, two independent kilohertz-frequency currents purportedly intersect where an interference field is generated. However, the effects of IFC on neurons within and outside the interference fi...
Preprint
Alzheimer's disease (AD) is one of the most significant health challenges of our time, affecting a growing number of the elderly population. In recent years, the retina has received increased attention as a candidate for AD biomarkers since it appears to manifest the pathological signatures of the disease. Therefore, its electrical activity may hin...
Preprint
Intracortical microstimulation (ICMS) of the primary somatosensory cortex (S1) can produce percepts that mimic somatic sensation and thus has potential as an approach to sensorize prosthetic limbs. However, it is not known whether ICMS could recreate active texture exploration-the ability to infer information about object texture by using one′s fin...
Conference Paper
Transcutaneous electrical stimulation (TES) of nerve fibers may be optimized by overcoming the impedance of the skin using high-frequency (HF) stimulation signals. The excitation properties of nerve fibers depend on the spatiotemporal distribution of the extracellular field, and therefore quantifying the potentials during HF-TES is warranted. We pr...
Chapter
The annual Computational Neuroscience Meeting (CNS) began in 1990 as a small workshop called Analysis and Modeling of Neural Systems. The goal of the workshop was to explore the boundary between neuroscience and computation. Riding on the success of several seminal papers, physicists had made "Neural Networks" fashionable, and soon the quantitative...
Conference Paper
Electrical stimulation of peripheral nerves is a widespread technique for the treatment of neurological diseases and disorders. However, peripheral stimulation typically requires surgical implantation of an electrode and a pulse generator. Transcutaneous stimulation with an external electrode and pulse generator could provide a noninvasive alternat...
Article
Full-text available
Artificial sensation via electrical or optical stimulation of brain sensory areas offers a promising treatment for sensory deficits. For a brain-machine-brain interface, such artificial sensation conveys feedback signals from a sensorized prosthetic limb. The ways neural tissue can be stimulated to evoke artificial sensation and the parameter space...
Article
In mining, rock classification plays a crucial role at different stages of the extraction process ranging from the design of the mine to mineral grading and plant control. In this paper we present a new method to improve rock classification using digital image analysis, feature selection based on mutual information and a voting process to take into...
Article
Full-text available
The tactile sense is being used in a variety of applications involving tactile human-machine interfaces. In a significant number of publications the classical threshold concept plays a central role in modelling and explaining psychophysical experimental results such as in stochastic resonance (SR) phenomena. In SR, noise enhances detection of sub-t...
Article
Stochastic resonance (SR) is the counterintuitive phenomenon in which noise enhances detection of sub-threshold stimuli. The SR psychophysical threshold theory establishes that the required amplitude to exceed the sensory threshold barrier can be reached by adding noise to a sub-threshold stimulus. The aim of this study was to test the SR theory by...
Thesis
El sentido del tacto ha sido usado en una diversidad de aplicaciones tales como la telecirugía, la robótica y la realidad virtual, entre otras. En la última década han surgido aplicaciones en que la adición de vibraciones mecánicas aleatorias (ruido táctil) permite mejorar la percepción de peque-ños estímulos táctiles. Este fenómeno, denominado res...
Article
Full-text available
This paper compares the classification performance of linear-system- and neural-network-based models in handwritten-digit classification and face recognition. In inputs to a linear classifier, nonlinear inputs are generated based on linear inputs, using different forms of generating products. Using a genetic algorithm, linear and nonlinear inputs t...

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