A new study published in the journal Current Biology suggests that babies start to experience pain as early as in the 35th week after conception.
Researchers from the University College London scanned the brain waves of 21 premature and 25 normal term babies and extracted blood by lancing their heels.
The researchers found that premature babies who were 28-35 weeks in womb displayed same level of brain activity for both lancing and touching but after 35 weeks, the brain activity was localized to specific areas for heel lances.
Lead researcher Dr Lorenzo Fabrizi said that the difference in brain activity showed that the babies started to differentiate between touch and pain. "We are asking a fundamental question about human development in this study - when do babies start to distinguish between sensations? In very young brains all stimulations are followed by 'bursts' of activity, but at a critical time in development babies start to respond with activity specific to the type of stimulation", he said.