Aberrant Local Synchrony in Distinct Mouse Models of Epileptic Encephalopathy

Identifying and quantifying synchronous activity of primary neuronal networks using multielectrode arrays (MEAs) can potentially provide a medium-throughput platform to screen potential therapeutics for genetic epileptic encephalopathies (EEs). However, successfully identifying screenable synchrony phenotypes in vitro poses significant experimental and analytical challenges. Primary neuronal cultures quickly become highly synchronous and certain measures of synchrony tend to peak and plateau, while other network activity features remain dynamic. High levels of synchrony may confound the ability to identify reproducible phenotypes in vitro for a subset of EEs. Reducing, or delaying the onset of, high levels of synchrony in vitro may increase the dynamic range of global synchrony measures to identify disease-relevant phenotypes in vitro, but such measures have not been established. We hypothesized that an emphasis on local (nearby) connectivity could elucidate reproducible disease-relevant synchrony phenotypes in cortical cultures not identified by current approaches. We show clear evidence of enriched local synchrony in 48-well MEAs that varies in amplitude during development of neuronal networks. Then, we show new topological-based measures are capable of identifying novel phenotypes of aberrant synchrony in distinct mouse models of EEs. Such topological synchrony measures may provide screenable phenotypes for certain brain diseases and may be further enhanced by experimental innovation reducing global levels of synchrony in primary neuronal networks. ### Competing Interest Statement D.B.G. is a founder of and holds equity in Praxis and Actio Bioscience. All other authors declare no competing financial interests.