Mother mice instinctively retrieve pups that wander from the nest. Now, that behaviour has been pinpointed to a specific brain circuit.

Previous research suggested that brain regions called the medial preoptic area (MPOA) and the ventral tegmental area (VTA) are important for maternal behaviours in rodents, but the precise pathways involved were not well understood. Scrutinizing the MPOA, Dayu Lin and her colleagues at the New York University School of Medicine found a select group of neurons that are particularly active during pup retrieval.

When the team stimulated these neurons in both mother mice and females that had never given birth, the animals hurried to fetch wandering pups. But when the neurons were chemically suppressed, mice were slower to retrieve wayward youngsters.

The MPOA neurons seem to drive pup retrieval by sending signals to the VTA. When the team blocked activity in the latter region, stimulation of MPOA cells failed to trigger pup retrieval.