Pain in infants and very young children

Interesting. Though, as always, these neurological facts don't by themselves entail any ethical conclusions. Of course, it would be nice to see standard practice err on the side of preventing as much pain as is clinically feasible.

"Pain, Hurt, and Harm: The Ethics of Pain Control in Infants and Children" in The New England Journal of Medicine (Vol. 331.8):

Many myths about pain in children have been discredited. One myth was the belief that very young infants do not have the neurologic capacity to experience pain. Neuroanatomical studies, however, have shown that by 29 weeks of gestation, pain pathways and the cortical and subcortical centers involved in the perception of pain are well developed, as are the neurologic systems for the transmission and modulation of painful sensations 15. Behavioral16,17 and physiologic18 studies have shown that even very young infants respond to painful stimuli. Premature infants undergoing surgery with minimal anesthesia, which was once standard practice, have significantly higher stress responses (by hormonal and metabolic measures) and significantly higher rates of complications and mortality than those given deeper anesthesia.19,20

A related misunderstanding is the belief that even if very young children experience pain, they have no memory of it, and therefore it has no lasting effect. However, recent studies have concluded that pain and distress, such as those associated with circumcision, can endure in memory, resulting, for example, in disturbances of feeding, sleeping, and the stability of the state of arousal.21 Preliminary data even suggest that early experiences of pain may produce permanent structural and functional reorganization of developing nociceptive neural pathways, which in turn may affect future experiences of pain.22