iScience
Volume 24, Issue 6, 25 June 2021, 102558
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Article
In vivo calcium imaging reveals disordered interictal network dynamics in epileptic stxbp1b zebrafish

https://doi.org/10.1016/j.isci.2021.102558Get rights and content
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Highlights

  • Calcium imaging in genetic epilepsy zebrafish model to study the interictal state

  • Network cascade activity was more prominent in stxbp1b mutant zebrafish

  • stxbp1b mutants characterized by spontaneous hyper-synchronized neuronal ensembles

Summary

STXBP1 mutations are associated with encephalopathy, developmental delay, intellectual disability, and epilepsy. While neural networks are known to operate at a critical state in the healthy brain, network behavior during pathological epileptic states remains unclear. Examining activity during periods between well-characterized ictal-like events (i.e., interictal period) could provide a valuable step toward understanding epileptic networks. To study these networks in the context of STXBP1 mutations, we combine a larval zebrafish model with in vivo fast confocal calcium imaging and extracellular local field potential recordings. Stxbp1b mutants display transient periods of elevated activity among local clusters of interacting neurons. These network “cascade” events were significantly larger in size and duration in mutants. At mesoscale resolution, cascades exhibit neurodevelopmental abnormalities. At single-cell scale, we describe spontaneous hyper-synchronized neuronal ensembles. That calcium imaging reveals uniquely disordered brain states during periods between pathological ictal-like seizure events is striking and represents a potential interictal biomarker.

Subject areas

Optical imaging
Molecular neuroscience
Cellular neuroscience

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