Influences of postconceptional age and postnatal experience on the development of auditory recognition memory in the newborn infant

We evaluated the effects of postconceptional age and postnatal experience on the development of neonatal auditory recognition memory. Three groups were tested: a premature newborn group (tested at 35-38 weeks postconceptional age, < or = 1 week old), a full-term newborn group (tested at 39-42 weeks postconceptional age, < or = 1 week old), and a full-term experienced group (tested at 39-42 weeks postconceptional age, > 1 week old; range 8-30 days). Event-related potentials were collected while infants listened to the maternal voice alternating with a stranger's voice. Postconceptional age was correlated with the development of recognition memory for the maternal voice while there were qualitative effects of postnatal experience on latency measurements. Maturity of auditory cortical responses was not correlated with recognition memory abilities. We conclude that maturation of the recognition memory pathways is primarily a function of postconceptional age with qualitative effects of postnatal experience. Maturation of the auditory recognition memory pathway is not contingent upon maturation of the "P2" peak thought to arise from primary auditory cortex.