Journal of neuroscience methods
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J. Neurosci. Methods · May 1997
Long term chronic recordings from peripheral sensory fibers using a sieve electrode array.
The use of an implanted micromachined silicon sieve electrode array to make long term chronic recordings from the glossopharyngeal nerve is described. The implant consists of an array of small holes in a silicon substrate, four of which are surrounded by electrodes connected with an integrally fabricated ribbon cable to a percutaneous headcap. Using this device we have been able to monitor the integrity of the electrodes from the time of implantation and subsequently to record evoked sensory responses from mechanoreceptors on the tongue.
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J. Neurosci. Methods · Mar 1997
Multi-unit recording from regenerated bullfrog eighth nerve using implantable silicon-substrate microelectrodes.
Multi-microelectrode silicon devices were developed for extracellular recording from multiple axons in regenerated eighth cranial nerves of American bullfrogs. Each includes a photolithographically defined array of holes and adjacent metal microelectrodes. A device is implanted within a transected eighth nerve; regenerating fibers grow through the holes en route to the brainstem. ⋯ The implantation success rate was low, due to surgical morbidity, device extrusion, and lack of nerve regeneration through some devices. Future designs will address these issues and incorporate transistor amplifiers on devices to increase signal-to-noise ratios. The potential of implanted silicon devices to simultaneously record from many axons offers an opportunity for multicellular studies of auditor, vestibular and seismic signal processing in the vertebrate inner ear.
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J. Neurosci. Methods · Mar 1996
Non-invasive measurement of the input-output properties of peripheral nerve stimulating electrodes.
A non-invasive method was developed to determine the input-output (I/O) properties of peripheral nerve stimulating electrodes. An apparatus was fabricated to measure the 3-dimensional (3-D) isometric torque generated at the cat ankle joint by electrical activation of the sciatic nerve. The performance of the apparatus was quantified, and the utility of the method was demonstrated by measuring the recruitment properties of multiple contact nerve cuff electrodes. ⋯ These data allowed determination of the regions of the nerve trunk that were activated by different electrode geometries and stimulus parameters. The positional stability of electrode recruitment properties could be quantified by measuring I/O characteristics at different limb positions. The methods described are useful for characterization of neural stimulating electrodes and for studies of motor system physiology.
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We have developed a flexible physiological monitoring and analysis system for physiological studies in which data are obtained over extended periods. Our system uses low-cost personal computer hardware to concentrate data from existing multiple monitoring devices. All monitored parameters are displayed on a single screen and recorded in a single file. ⋯ This program assigns the analog channels of an A/D board to particular physiological parameters by initially reading a configuration file, which also describes the alarm conditions and analysis routine for each parameter. All hardware specific code is isolated into well-defined modules. The program is both highly flexible with regard to different sets of parameters and highly portable for different experimental and computer environments.
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J. Neurosci. Methods · Apr 1995
On the simultaneous electrophysiological measurements of neurotransmitter release and perineural calcium currents from frog motor nerve endings.
Ca2+ currents from the perineural region of motor nerve endings were measured together with evoked acetylcholine (ACh) release (i.e., end-plate potentials EPPs) in frog skeletal muscle in an attempt to define experimental conditions in which simultaneous measurements of both phenomena were feasible. In a solution containing low Ca2+ (0.9 mM), high Mg2+ (10 mM) and modest concentrations of K+ channel blockers (250 microM tetraethylammonium, 100 microM 3,4,-diaminopyridine), reliable measurements of perineural Ca2+ currents were possible. For convenience, this solution will be termed 'Ca2+ current' Ringer. ⋯ NaF (10 mM), which stimulates ACh release, produced parallel increases in EPPs and perineural Ca2+ currents. NG-cyclohexyladenosine (CHA), an A1 adenosine receptor agonist, inhibits ACh release without effects on perineural currents. The results suggest that the concurrent electrophysiological recording of Ca2+ currents and ACh release in Ca2+ current Ringer is a reliable experimental approach for determining whether drugs or disease states affect ACh release by acting on Ca2+ channels in the presynaptic membrane.