By wirelessly recording the brain activity of rat pups during interaction with their mother, Catia Teixeira and colleagues provide evidence for a direct connection between maternal care and the neurotransmitter serotonin -- two factors known to be crucially involved in brain development.

The researchers demonstrate that a mother's presence in the nest increases activity in the pups' prefrontal cortex, a slowly developing brain region rich in serotonin receptors. Blocking these receptors counteracted the effect, while treating isolated pups with the selective-serotonin-reuptake-inhibitor fluoxetine increased prefrontal cortex activity similarly to that observed in the mother's presence.

These results implicate maternal contact and the serotonin system as important regulators of neuronal activity in the developing brain.