Effects of maternity on auditory event-related potentials to human sound

Auditory event-related brain potentials (ERPs) were recorded in response to an emotional (a baby's cry) and a neutral (a word) stimulus in a group of mothers 2-5 days after childbirth (n = 20) and in control women (n = 18) wh o were not in the state of early motherhood. For each mother, her own infan t's cry was recorded and used as the cry stimulus, whereas a strange baby's cry was used for control women. The word stimulus was identical for both g roups. Stimuli were presented in intermittent trains in order to study the arousal responses to the first stimuli of the trains, and refractoriness of ERPs during stimulus repetition. The N100 responses were significantly lar ger in amplitude in mothers than in control women, not only to the emotiona l cry stimuli but also to the neutral word stimuli. The finding suggests a general increase in alertness and arousal in mothers, which may be necessar y in enabling the mother to be continuously alert to her infant's needs. Th is allows good care of the infant and may be essential in building an emoti onal tie between the mother and her child. NeuroReport 12:2975-2979 (C) 200 1 Lippincott Williams & Wilkins.