Impaired γ-aminobutyric acid (GABA) signalling is known to have a role in epilepsy, highlighting this process as a potential therapeutic target. Hunt et al. grafted GABAergic progenitors into the hippocampus of epileptic adult mice. The cells migrated throughout the hippocampal subfield and differentiated into functional inhibitory interneurons. Moreover, cell transplantation reduced seizure frequency by 92% and restored behavioural deficits in domains such as spatial learning.