Coalescence of deep and superficial epileptic foci into larger discharge units in adult rat neocortex

Highlights • Multiple electrode arrays were used to characterize epileptic discharges in adult rat somatosensory cortex slices. • Data show that an epileptic focus consists of multiple, small, discreet firing units over several cortical layers. • During the recording these gradually become coupled, coalescing into larger coherent units. • These findings illustrate an emerging network property in the development of an epileptic focus.