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Neural signals can be generated or blocked by extracellular electrodes or magnetic coils. New results about artificial excitation are based on a compartmental model of a target neuron and its equivalent electrical network, as well as on the theory of the generalized activating function. The analysis shows that: (i) in most cases, the origin of artificial(More)
OBJECTIVES Analysis of the computed recruitment order of an ensemble of ventral and dorsal root fibers should enlighten the relation between the position of a bipolar electrode and the observed order of muscle twitches. MATERIAL AND METHODS Thresholds of selected spinal root fibers are investigated in a two step procedure. First the electric field(More)
Differences in neural geometry and the fact that the soma of the human cochlear neuron typically is not myelinated are reasons for disagreements between single fiber recordings in animals and the neural code evoked in cochlear implant patients. We introduce a compartment model of the human cochlear neuron to study the excitation and propagation process of(More)
We have demonstrated that non-patterned electrical stimulation of the lumbar cord can induce stepping-like activity in the lower limbs of complete spinal cord injured individuals. This result suggested the existence of a human lumbar locomotor pattern generator, which can convert a tonic input to a rhythmic motor output. We have studied the human lumbar(More)
Continuous epidural stimulation of lumbar posterior root afferents can modify the activity of lumbar cord networks and motoneurons, resulting in suppression of spasticity or elicitation of locomotor-like movements in spinal cord-injured people. The aim of the present study was to demonstrate that posterior root afferents can also be depolarized by(More)
STUDY DESIGN It has been previously demonstrated that sustained nonpatterned electric stimulation of the posterior lumbar spinal cord from the epidural space can induce stepping-like movements in subjects with chronic, complete spinal cord injury. In the present paper, we explore physiologically related components of electromyographic (EMG) recordings(More)
  • F Rattay
  • 1989
This paper presents the mathematical basis for analysis as well as for the computer simulation of the stimulus/response characteristics of nerve or muscle fibers. The results follow from the extracellular potential along the fiber as a function of electrode geometry. The theory is of a general nature but special investigations are made on monopolar,(More)
Four models are discussed which can be used to predict the behavior of warm-blooded axons, when excited by electric fields. Up to now, most results were obtained with the Frankenhaeuser-Huxley model, but nearly all of them are wrong in time scale and the cathodic block phenomenon was not observable because the temperature dependence of the gating mechanism(More)
BACKGROUND Our knowledge about the neural code in the auditory nerve is based to a large extent on experiments on cats. Several anatomical differences between auditory neurons in human and cat are expected to lead to functional differences in speed and safety of spike conduction. METHODOLOGY/PRINCIPAL FINDINGS Confocal microscopy was used to(More)