Auditory Discrimination during Rem and Non-Rem Sleep in Women before and after Delivery

Abstract

According to Oswald (6), the use of a mother's response to sound from her child as an example of the ability to discriminate auditory stimuli during sleep dates back to 1830. Recent references to this ability in mothers can be found in the papers of Evans et al. (3) and Wilson and Zung (11, 12). Therefore, it is surprising that this response has not been studied in the labora tory, although other forms of auditory dis crimination have been. Oswald found that his subjects were more likely to awaken to the sound of their own name than to the sound of the name of another person. Wilson and Zung (11) reported that there is a difference in the general arousal system between men and women for insignificant stimuli but they found none for significant ones. These authors hypothesized that facili tation of arousal in women is related to the feeding of newborn infants and leads to the capacity of the mother to be alerted to the cry of the infant while she is asleep. Indeed it is known that the sleep architecture is modified during late pregnancy and the early postpartum period (4).The aim of the present study was to deter mine, under laboratory conditions, the dif ferences, in awakening threshold in pregnant women to a baby's cry, to a voice saying "baby is crying" and to a speech noise, both before delivery (phase I of the experiment) and after (phase II). MethodsThe sample consisted of six women, aged 21 to 32 years. They were about 8V2 months pregnant during phase I. Sleep EEG record-

A role for the thalamus in danger discrimination during sleep

“…The absence of sensory-evoked awakenings during REM sleep in our study re ects the higher sensory threshold reported during that state in humans 50,51 and animals 21 in similar experimental paradigms, presumably as a protective mechanism against disruptive environmental stimuli 27 .In addition, the restorative functions of REM sleep are seen as prerequisites for effective waking function with brief awakenings from REM sleep preparing the organism for immediate ght or ight 28,52 , as compared to awakenings from NREM sleep. Our ndings, along with previous research 10,11,22,27,28,30,50,52,53 , collectively support the concept of NREM sleep as a vigilant state for monitoring the environment for potential threats, and REM sleep representing a disconnected state, potentially increasing vulnerability.…”

“…The sleeping brain maintains a residual ability to respond to external sensory information 8,9 as evidenced by the high probability of awakening to personally relevant auditory stimuli in humans (e.g., one's own name, baby cry) 7,[10][11][12] , and the sleep-dependent improvement of performance in word pair learning 13 , semantic discrimination 12,14,15 , and oddball auditory paradigm 2 during sleep. Accordingly, in both humans and animals, auditory evoked responses persist in thalamo-cortical circuits during NREM [16][17][18][19] and REM sleep 20 and arousal circuits 21 that induce sleep-to-wake transitions depending on the brain state, ongoing activity, oscillations, and cue saliency 22 .…”

Effects of an intervention with drinking chamomile tea on sleep quality and depression in sleep disturbed postnatal women: a randomized controlled trial

“…Research has shown that interrupted sleep and increased wake time at night may lead to poor sleep efficiency and less the total sleep time in postpartum women (Poitras et al 1973, Campbell 1986, Lentz & Killien 1991, Swain et al 1997, Gay et al 2004. Known causes of sleep disturbance include physical discomfort, infant crying, disturbance by bed partners, and perceived stress, among others.…”

Biorhythmic variations in consciousness and psychological functions.

“…Using nonsignificant stimuli, the threshold for a behavioral response is in general highest in REM and in stage 4 sleep, and lower in the lighter stages of NREM sleep (Williams, Hammack, Daly, Dement and Lubin, 1964). But with highly significant stimuli, such as pain or the cry of a mother's baby, the threshold appears to be lowered in REM sleep (Koella, 1968;Pisano, Rosadini, Rossi and Zattoni, 1966;Poitras, Thorkildsen, Gagnon and Naiman, 1973;Williams, Morlock and Morlock, Note 2). This issue, however, needs further clarification.…”