The study looked at 10 healthy infants aged between one and six days old and 10 healthy adults aged 23-36 years. Infants were recruited from the John Radcliffe Hospital, Oxford, and adult volunteers were Oxford University staff or students.
During the research babies, accompanied by parents and clinical staff, were placed in a Magnetic Resonance Imaging (MRI) scanner where they usually fell asleep. MRI scans were then taken of the babies' brains as they were 'poked' on the bottom of their feet with a special retracting rod creating a sensation 'like being poked with a pencil' – mild enough that it did not wake them up. These scans were then compared with brain scans of adults exposed to the same pain stimulus.