There is a long-standing controversy regarding the role played by GABA-mediated neurotransmission in the generation of epileptiform activity. While some research suggests that ictogenesis is accompanied by the failure of inhibition to contain the spread of excitation, other studies argue that GABA-mediated signalling may paradoxically contribute to the epileptiform discharges. Using optogenetic approach we aim to understand the role of different populations of interneurones in seizure generation.