This study reveals that neuronal brain activity is not accompanied by a blood-flow response in the brains of newborn mice. Here, mice were observed at three ages (7 days, 13 days and adult). The left column shows the neuronal activity in response to hind-paw stimulation for each age group. The right column shows the blood-flow response to that same stimulus. The complexity of neuronal activity increases between ages 7 and 10 days, though it is not until the mouse reaches adulthood that scientists observe a relationship between that neuronal activity and blood-flow response.