Spreading depression: Evidence of five electroencephalogram phases.
Journal article, 2014

Spreading depression (SD), a self-propagating wave of astroglial and neuronal depolarization, is an accompaniment of several neurological disorders including epilepsy. Its well-described features are initial depolarization, followed by EEG flattening. In this in vivo study in awake animals, the relationship of SDs to epileptiform activity was re-examined. We assessed SDs generated by mechanical stimulation and by metabolic inhibition with fluorocitrate. In addition to identifying prolonged EEG depression, we identified two periods, one prior to and another during depression, characterized by increases in power of specific frequencies that were sometimes associated with epileptiform discharges. The first period was characterized by ripple activity close to the induction site (88% of SDs with intracortical electrodes). The second period was characterized by localized low-frequency spikes (100% with dural screw electrodes, 65% with intracortical electrodes). By using fluorocitrate to induce SDs, the initial period was also characterized by runs of spikes (52%). Finally, with SDs induced by both methods, there was a period at the end of depression when additional, unprovoked SDs occurred (20%). Five stages of SD were defined by these phenomena, in the order: excitation, depression, excitation, depression, SD, with metabolic inhibition enhancing the expression of epileptiform spiking.

high-frequency activity

fluorocitrate

epileptiform discharges

impedance

ripples

Author

Marita Broberg

Flinders University

Kenneth Pope

Flinders University

Torsten Olsson

Chalmers, Signals and Systems, Signalbehandling och medicinsk teknik, Biomedical Signals and Systems

C William Shuttleworth

University of New Mexico School of Medicine

John Willoughby

Flinders University

Journal of Neuroscience Research

0360-4012 (ISSN) 1097-4547 (eISSN)

Vol. 92 10 1384-1394

Subject Categories

Medical Laboratory and Measurements Technologies

Neurosciences

Areas of Advance

Life Science Engineering (2010-2018)

DOI

10.1002/jnr.23412

PubMed

24840241

More information

Created

10/8/2017