Interneuron progenitor cells transplanted into the hippocampus can be incorporated into neuronal circuits and improve outcomes after traumatic brain injury (TBI) in a mouse model, according to new research published in Nature Communications. Bingyao Zhu and colleagues isolated inhibitory interneuron progenitors from the medial ganglionic eminence of mouse embryos and transplanted these cells into the hippocampus in mice that had been subjected to controlled cortical impact — a mechanical model that is thought to accurately replicate the effects of TBI in humans. The cells were shown to undergo maturation and integrate functionally into hippocampal circuits. The mice that received the transplants showed improvements in memory precision and reductions in post-traumatic seizures, indicating restoration of inhibitory network function in the hippocampus.