  The dynamics underlying epileptic seizures are well understood. We present a
novel analysis of seizure-like events (SLEs) in an \textit{ex vivo} whole
hippocampus, as well as a modeling study that sheds light on the underlying
network dynamics. We show that every SLE can be divided into two phases. During
the first, SLE dynamics are driven by the intra-network interaction of a
network exhibiting high internal synchrony. The second phase is characterized
by lead switching, with the leading region exhibiting low internal synchrony.
We show that the second phase dynamics are driven by inter-network feedback
among multiple regions of the hippocampus.
