This study determined the response of action potentials during ventricular fibrillation (VF) to timed monophasic and biphasic shocks. A floating glass microelectrode was used to record intracellularly from the anterior right ventricle in 10 open-chest dogs. After 10 seconds of electrically induced VF, 5-millisecond monophasic and 2.5/2.5-millisecond biphasic shocks or 16-millisecond monophasic ...

Dendrodendritic inhibition between mitral and granule cells in the olfactory bulb is thought to play an important role in olfactory discrimination. In this issue of Neuron, explore the propagation of action potentials along the secondary dendrites of mitral cells and their modulation by dendrodendritic inhibition.

The essential optical components include a 5 mW polarized laser (HeNe); single mode, polarization preserving optical fiber with couplers; Wollaston prism, birefringent plate; water immersion 20x microscope objective; electro-optic modulator, and polarization analyzer. The interferometric microscope needs to be compact and stiff, a combination that can be achieved with Microbench components (LIN...

Action potentials have a central role in the nervous system and in many cellular processes, notably those involving ion channels. The accurate measurement of action potentials requires efficient coupling between the cell membrane and the measuring electrodes. Intracellular recording methods such as patch clamping involve measuring the voltage or current across the cell membrane by accessing the...

The potential changes associated with the conduction of impulses in muscle and nerve can be interpreted only if they are led off from small regions of the tissue. This is accomplished most satisfactorily by recording monophasic potentials or by recording the potentials in the intact tissue with differential electrodes. In the study of the stomach only tJhe second of these methods is practical. ...

The goal of assignments related to this document is to experiment with a numerical simulation of the cardiac action potential. The form of this simulation is just as described in class, using the Hodgkin-Huxley formalism and differential equations to reproduce the currents responsible for the action potential. To simulate the cardiac action potential, it is necessary to expand the number of cha...

Medial gastrocnemius and sural nerves in one hindlimb of the cat were transected and prevented from regenerating. After periods ranging from 29-273 days, compound action potentials were recorded from axotomised and contralateral control nerves. The amplitude and integrated area of action potentials decreased and conduction velocity slowed following axotomy. The area under compound action potent...

Noise induced excitability is studied in type I and II Morris–Lecar neurons subject to constant sub threshold input, where fluctuations arise from sodium and potassium ion channels. Ion channels open and close randomly, creating current fluctuations that can induce spontaneous firing of action potentials. Both noise sources are assumed to be weak so that spontaneous action potentials occur on a...

There is growing evidence in support of the hypothesis that far-field potentials are recorded when action potentials encounter discontinuities in the surrounding volume. The present study found further support for this hypothesis using two methods of experimentation. The first method recorded potentials when the action potential from an isolated bullfrog sciatic nerve in a hemicylindrical volum...