Babies distinguish pain from touch at 35-37 weeks

Babies can distinguish painful stimuli as different from general touch from around 35-37 weeks gestation - just before an infant would normally be born - according to new research. In a study published online in the journal Current Biology, scientists show that neural activity in the brain gradually changes from an immature state to a more adult-like state from 35 weeks of development. This change may indicate that neural circuitry allows babies to process pain as a separate sensation from touch. Rebeccah Slater, UCL Neuroscience, Physiology and Pharmacology, said: "Premature babies who are younger than 35 weeks have similar brain responses when they experience touch or pain. After this time there is a gradual change, rather than a sudden shift, when the brain starts to process the two types of stimuli in a distinct manner." Scientists looked at the brain activity of 46 babies at the University College Hospital Elizabeth Garrett Anderson Wing. 21 babies in the study were born prematurely, giving scientists the opportunity to measure activity at different stages of human brain development, from babies at just 28 weeks of development through to those born 'full term' at 37 weeks. Using electroencephalography (EEG), the scientists measured the babies' electrical brain activity when they were undergoing a routine heel lance - a standard procedure essential to collect blood samples for clinical use.