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

Abstract

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) who were not in the state of early motherhood. For each mother, her own infant'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 groups. 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 larger in amplitude in mothers than in control women, not only to the emotional cry stimuli but also to the neutral word stimuli. The finding suggests a general increase in alertness and arousal in mothers, which may be necessary in enabling the mother to be continuously alert to her infant's needs. This allows good care of the infant and may be essential in building an emotional tie between the mother and her child.

The impact of stimulus type and early motherhood on attentional processing

“…Thus no specificity of responsiveness to infant cries in mothers was shown. This confirms our earlier finding of a general increase in alertness and arousal in mothers presented with human stimuli (Purhonen et al, 2001) and demonstrates that it also extends to conventional tone stimuli.…”

“…These deficits are typically seen in schizophrenia, a disease characterized by difficulties in evaluating stimulus input (Boutros, Belger, Campbell, D'Souza, & Krystal, 1999). Our earlier study (Purhonen et al, 2001) demonstrated that N100 amplitudes in mothers were higher but habituation was the same in mothers and in control women, suggesting that the stimulus gating mechanisms were intact in mothers and function similarly to those of control women. In the present study we saw an enhancement of the N100 amplitude in mothers, but the N200 and P300 amplitudes were similar in mothers and in control women for all studied stimulus types.…”

“…The project consisted of two ERP paradigms: the habituation and a modification of the novelty oddball paradigm. The results of infant paradigms (Purhonen, Kilpeläinen-Lees, Valkonen-Korhonen, Karhu, & Lehtonen, 2004 and of the adult habituation paradigm (Purhonen Kilpeläinen-lees, Pääkkönen, Yppärilä, Lehtonen, & Karhu, 2001) have been already published. The adult habituation paradigm revealed enhanced N100 amplitudes to human stimuli in mothers who had recently given birth compared to control women, which was suggested to reflect an increased level of arousal and alertness in the mothers.…”

Cerebral processing of mother's voice compared to unfamiliar voice in 4-month-old infants

“…In the beginning, family members and especially the mother are the most important caretakers and the interplay between mother and infant is bi-directional (Stern, 1985). We have shown earlier that few days after childbirth the mothers of the infants who were studied in the present study showed an increased level of arousal and alertness to own infant's cry and to other auditory human stimuli (Purhonen et al, 2001). The present study suggests that in infants, the mother's voice is processed differently from, and it may attract more attention than an unfamiliar female's voice.…”

The neural basis of responsive caregiving behaviour: Investigating temporal dynamics within the parental brain

“…For example, mothers were found to demonstrate shorter N1 latencies in response to infant facial expressions [78] and greater amplitude of N1 peaks in response to cry vocalisations [112] and facial expressions [79] compared to non-mothers. However, other studies have demonstrated no effect of parental status on P1 responses [80].…”