The nucleus reuniens orchestrates prefrontal-hippocampal synchrony during spatial working memory

•The nucleus reuniens reciprocally connects the hippocampus and prefrontal cortex.•The nucleus reuniens is critical for spatial working memory in rodents.•Inactivation of reuniens disrupts hippocampal-prefrontal synchronization.•Questions remain about communication in the prefrontal-thalamo-hippocampal circuit.