Very fast oscillations (VFOs, >80 Hz) are seen in normal neocortex during the up-state of slow oscillations and cortical activations. However, VFOs are seen more frequently in seizure onset zones, especially at the beginning of seizures. Previous models show that an axonal plexus (network of axons coupled by gap junctions) can easily produce VFOs. Moreover, VFOs and seizures can be blocked by gap junction blockers in experiment. I will present a model of a neocortical axonal plexus, which shows that the somatic voltage can control AP propagation across gap junctions on the main axon but not side collaterals. Therefore, axonal sprouting may lead to many uncontrollable gap junctions which can generate persistent VFOs. Hence, networks of sprouted axons connected by gap junctions may kindle postsynaptic cells, leading to epilepsy.