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We studied the use of physiologically based, multisite, intrafascicular electrical stimulation of the sciatic nerve to achieve ripple-free contractions and sustained, fatigue-resistant forces over a physiological range of forces in cat gastrocnemius muscle. Electrode arrays containing 100, 0.5-1.5-mm-long penetrating microelectrodes were inserted into the(More)
We developed a multicompartmental Hodgkin-Huxley model of the Hermissenda type-B photoreceptor and used it to address the relative contributions of reductions of two K+ currents, I a and I C, to changes in cellular excitability and synaptic strength that occur in these cells after associative learning. We found that reductions of gC, the peak conductance of(More)
Because the Hermissenda eye is relatively simple and its cells well characterized, it provides an attractive preparation for detailed computational analysis. To examine the neural mechanisms of learning in this system, we developed multicompartmental models of the type-A and type-B photoreceptors, simulated the eye, and asked three questions: First, how do(More)
Functional electrical stimulation (FES) is a general term for therapeutic methods that use electrical stimulation to aid or replace lost ability. For FES systems that communicate with the nervous system, one critical component is the electrode interface through which the machine-body information transfer must occur. In this paper, we examine the influence(More)
Neurons are notoriously noisy devices. Although the traditional view posits that noise degrades system performance, recent evidence suggests that noise may instead enhance neural information processing under certain conditions. Here we report that random channel and synaptic noise improve the ability of a biologically realistic computational model of the(More)
We present a phase model of a repetitively firing neuron possessing a phase-dependent stochastic response to periodic inhibition. We analyze the dynamics in terms of a stochastic phase map and determine the invariant phase distribution. We use the latter to compute both the distribution of interspike intervals (ISIs) and the stochastic winding number (mean(More)
In a companion paper we showed that random channel and synaptic noise improve the ability of a biologically realistic, GENESIS-based computational model of the Hermissenda eye to encode light intensity. In this paper we explore mechanisms for noise-induced improvement by examining contextual spike-timing relationships among neurons in the photoreceptor(More)
As the field of neuroprosthetic research continues to grow, studies describing the foreign body reaction surrounding chronic indwelling electrodes or microelectrode arrays will be critical for assessing biocompatibility. Of particular importance is the reaction surrounding penetrating microelectrodes that are used to stimulate and record from peripheral(More)
We report a case of a massive haemothorax following bilateral surgical resection of apical bullae. Occult bleeding was not recognized until the onset of a life-threatening circulatory collapse associated with metabolic acidosis and a fall in haemoglobin level. Using a thoracotomy, large amounts of blood were evacuated from the thoracic cavity and bleeding(More)