Inhomogeneous propagation of cortical spreading depression-detection by electro- and magnetoencephalography in rats.
Spreading depression (SD) propagates in cortical regions that are different in their morphological and functional characteristics. We tested whether the propagation pattern of spreading depression was different between parts of the cortex. In six adult rats, we recorded the ECoG by a 4 x 4 electrode array that covered parts of the frontal, parietal cortex and the cingulate cortex. Simultaneously a 16-channel magnetoencephalogram was recorded to characterize the development and direction of intracortical ion movements accompanying this phenomenon. Spreading depression was initiated by occipital application of 0.3 molar KCl solution. Depolarization was observed, at first, at lateral cortical regions and then at medial cortical regions. Thereafter, the propagation velocity increased in medial cortical regions and was faster than in lateral regions. Negative potential shifts were detected by all electrodes, but the depolarization reached a maximum over lateral and caudal cortical regions. The recorded magnetic fields indicated the same orientation of currents underlying these fields, which was perpendicular to the wave front and points away from the depolarization region. Overall, the data indicated that propagation patterns of spreading depression differed between parts of the cortex and, thus, propagation was inhomogeneous. This propagation was accompanied by strong currents parallel to the cortical surface.
Eiselt
Michael
M
Institute of Pathophysiology and Pathobiochemistry, Klinikum der Friedrich-Schiller-Universität, D-07740 Jena, Germany. Michael.Eiselt@mti.uni-jena.de
Giessler
Frank
F
Platzek
Dieter
D
Haueisen
Jens
J
Zwiener
Ulrich
U
Röther
Joachim
J
D000818:Animals; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology; D013181:Cortical Spreading Depression / Q000187:drug effects / Q000502:physiology*; D004569:Electroencephalography; D005625:Frontal Lobe / Q000187:drug effects / Q000502:physiology*; D006179:Gyrus Cinguli / Q000187:drug effects / Q000502:physiology*; D015225:Magnetoencephalography; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D010296:Parietal Lobe / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats
D011188:Potassium