Temporal pattern and spectral complexity as stimulus parameters for eliciting a cardiacorienting reflex inhuman fetuses

Abstract

The purpose of this study was to determine whether temporal pattern and/or spectral complexity were important stimulus parameters for eliciting a cardiac orienting reflex (OR) in low-risk human fetuses. Each of28 term fetuses was exposed to four sounds formed from the four different combinations of temporal pattern (pulsed, continuous) and spectral complexity (sine wave, /3/). The fetal cardiac electrical signal was captured transabdominally at a rate of 1024Hz, and fetal R-waves were extracted by using adaptive signal-processing techniques. We found that pulsed sounds elicited a significantly greater decrease in heart rate (HR) than did continuous sounds. However, the HR response was relatively unaffected by spectral complexity. For the pure tone and the phoneme used in this study, our results indicate that temporal characteristics were more effective at eliciting a cardiac OR in human fetuses than was spectral complexity.Successful word recognition involves the perception and discrimination of different sounds, recall of a cognitive representation of specific sounds, and segmentation of speech into the correct sequence of words (Jusczyk, 1993). Although these skills are acquired at different times during development (Jusczyk, 1993), it appears that newborn infants already possess remarkable discriminatory capabilities: Two-day-old infants can discriminate between stop consonant contrasts (e.g., ba vs. da) and between following vowel contrasts (e.g., ba vs. bi; Bertoncini, Bijeljac-Babic, Blumstein, & Mehler, 1987), and by 4 days postnatal age, infants can encode sufficiently detailed information to detect the addition of a new syllable to a set of familiar ones

Fetal responses to induced maternal relaxation during pregnancy

“…This possibility has been broached previously based on the rapidity of onset of a fetal response to a maternal event (DiPietro et al, 2003;Novak, 2004). FHR responses have been observed within seconds of disruptions of the maternal environment in investigations of sensory capacities, including maternal postural changes (Lecaneut et al, 2002) and auditory stimuli (Groome et al, 2000) and it is clear that sounds generated by maternal vasculature and the digestive tract are prominent in the uterine auditory environment (Querleu, Renard, Boutteville, & Crepin, 1989). It is possible that induced maternal relaxation may generate a biphasic response that includes a rapid sensory-mediated component as well as a secondary response mediated by neurohormonal or vasodilatory processes that extends beyond the confines of this study's protocol.…”

Audiotactile interactions in temporal perception

“…Audiotactile interactions in rhythm perception and sensorimotor synchronization Some authors have observed that, whereas the spatial properties of the objects-typically related to visual functions-develop after birth, some temporal properties, such as synchrony, tempo, and rhythm, are experienced during prenatal life, through vestibular, tactile, and auditory stimulation (e.g., Groome et al, 2000;Woodward & Guidozzi, 1992). The different line of development of the sensory modalities would contribute in generating specific "salience hierarchies" for object/event properties, with the processing of auditory-somatosensory synchrony-such as the one elicited by the maternal heartbeat-being one of the first sensory experiences we humans are exposed to (Lickliter & Bahrick, 2000).…”

Effects of prenatal visual stimulation on growth and heart rate in bobwhite quail (Colinus virginianus)

“…Heart rate decreased in response to auditory stimulation, with a greater decrease occurring during active sleep than quiet sleep. A similar study found that pulsed sounds elicited a greater heart rate decrease than did continuous sounds, regardless of the spectral complexity (Groome et al, 2000).…”