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Coupled intra- and extracellular Ca2+ dynamics in recurrent seizure-like events

Authors

  • Nóra Szilágyi,

    1. Department of Physiology and Neurobiology, Eötvös Loránd University, Múzeum krt. 4/A. H-1088 Budapest, Hungary
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  • Richárd Kovács,

    1. Department of Neurochemistry, Chemical Institute, Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri út 59-67. H-1025 Budapest, Hungary
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  • Julianna Kardos

    1. Department of Neurochemistry, Chemical Institute, Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri út 59-67. H-1025 Budapest, Hungary
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: Dr Julianna Kardos, as above.
E-mail: jkardos@cric.chemres.hu

Abstract

We considered the evolution of Ca2+ oscillation dynamics in recurrent seizure-like events. Dynamic system behaviour was characterized in the state space reconstructed from intra- and extracellular [Ca2+] fluctuations simultaneously measured in cultured rat hippocampal slices under low-[Mg2+] conditions. When associated in the seizure-like event, these fluctuations occurred on a restricted set, the attractor, embedded in the full state space with less than five degrees of freedom. Instantaneous relative phase differences indicated field potential-driven phase jumps locked onto seizure-like events. To account for recurrent dynamics, calculations were performed on different extensions of a model for Ca2+ oscillation. These identified bidirectional, asymmetrical coupling of extracellular with intracellular (cytosolic, Ca2+ store, mitochondrial) Ca2+ dynamics as critical in its development.

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