Nociceptive pathways are functional following birth, and acute responses to noxious stimuli have been documented from early in development in clinical and laboratory studies. The ability of noxious afferent input to alter the level of sensitivity of nociceptive pathways in the adult nervous system, with, for example, the development of central sensitization, is well established. However, the developing nervous system has additional susceptibilities to alterations in neural activity, and pain in early life may produce effects not seen following the same input at older ages. As a result, early tissue injury may lead to persistent changes in somatosensory processing and altered sensitivity to future noxious stimuli. Furthermore, there is increasing evidence that neonatal pain can result in long-term changes in cognitive and affective behavior. Effects of pain in early life are superimposed on a highly plastic developing system, and long-term outcomes vary depending on the type and severity of the injury, and on the evaluation methods used. Laboratory studies allow evaluation of different injuries, potential confounding factors, underlying mechanisms, and potential analgesic modulation.
Developmental conditions modulate DNA methylation at the glucocorticoid receptor gene with cascading effects on expression and corticosterone levels in zebra finches
