Computer simulations indicate that electrical field effects contribute to the shape of the epileptiform field potential

doi:10.1016/0306-4522(85)90245-3

Neuroscience

Volume 15, Issue 4, August 1985, Pages 947-958

https://doi.org/10.1016/0306-4522(85)90245-3 Get rights and content

Abstract

In the presence of convulsant drugs such as picrotoxin, neurons in the hippocampal-slice preparation generate synchronized depolarizing bursts. This synchrony occurs on a time scale of tens of milliseconds and is produced by excitatory synaptic interactions between neurons. The synaptic interactions themselves occur on a time scale of tens of milliseconds. The “epileptiform” local-field potential during such synchronized bursts is comb-shaped (“ringing”), whereas the field potential expected if action potentials in neighboring neurons were uncorrelated is noisy and not comb-shaped. This suggests that individual action potentials are locally synchronized on a time scale of 1 ms. We have previously shown, using computer simulations, that electrical interactions—mediated by currents flowing in the extracellular medium—can plausibly explain action-potential synchronization in experiments where chemical synapses are blocked. The present simulations demonstrate that electrical interactions can also account for action-potential synchronization—and thus the “ringing” shape of the field potential—during epileptiform bursts, where excitatory synapses are functional.

The field potential is thus a modulating influence on, as well as a reflection of, underlying neuronal transmembrane events.

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Research paperComputer simulations indicate that electrical field effects contribute to the shape of the epileptiform field potential

Abstract

Jap. J. Pharmac.

Brain Res. Bull.

Brain Res.

Brain Res.

Brain Res.

Neuroscience

Biophys. J.

Expl Neurol.

Brain Res.

Brain Res.

Brain Res.

Brain Res.

Neuroscience

Neuroscience

Neuroscience

Epileptiform burst afterhyperpolarization: calcium-dependent potassium potential in hippocampal CA1 pyramidal cells

Science, Wash.

Voltage-clamp analysis of mossy fiber synaptic input to hippocampal neurons

J. Neurophysiol.

Mechanisms of facilitation of antidromic population spikes by iontophoretic applications of acetylcholine into hippocampal CA3 region, in situ

Soc. Neurosci. Abstr.

Changes in the extracellular volume in the cerebral cortex of cats in relation to stimulus induced epileptiform afterdischarges

Reduced inhibition during epileptiform activity in the in vitro hippocampal slice

J. Physiol., Lond.

Recent evidence for and possible significance of gap junctions and electrotonic synapses in the mammalian brain

Modification of neuron properties by electrotonic synapses. II. Burst formation by electrotonic synapses

J. Neurophysiol.

Optical monitoring of electrical activity. Detection of spatiotemporal patterns of activity in hippocampal slices by voltage-sensitive probes

Low-calcium field burst discharges of CA1 pyramidal neurones in rat hippocampal slices

J. Physiol., Lond.

Research paper
Computer simulations indicate that electrical field effects contribute to the shape of the epileptiform field potential