Effects of prenatal sensory stimulation on heart rate and behavioral measures of arousal in bobwhite quail embryos.

Although a number of studies have demonstrated the effects of altered prenatal experience on subsequent behavioral development, how these effects are achieved remains a topic of enduring interest. The present study examined the immediate effects of unimodal and multimodal prenatal sensory stimulation on physiological and behavioral arousal in bobwhite quail embryos. Embryos were videotaped and their heart rate was monitored during a 4-min exposure period to (a) no supplemental sensory stimulation, (b) unimodal auditory stimulation, (c) unimodal visual stimulation, (d) two sources of concurrent auditory stimulation, or (e) concurrent auditory/visual stimulation. Results indicated that quail embryos' overall activity levels and heart rate can be significantly affected by the type of prenatal sensory stimulation provided during the period prior to hatching. In particular, multimodal stimulation increased both behavioral activity levels and heart rate compared to controls. Across the unimodal and intramodal groups, however, behavioral and physiological measures revealed different patterns of activity in response to supplemental sensory stimulation, highlighting the value of using multiple levels of analysis in exploring arousal mechanisms involved in prenatal perceptual responsiveness.