The Influence of Maternally Regulated Prenatal Sensory Experience on Postnatal Motor Coordination in Neonatal Bobwhite Quail (Colinus virginianus)

Comparative animal studies aid in understanding how prenatal sensory experiences regulated by maternal activity facilitate or interfere with growth and phenotype development. However, there is a paucity of information on how prenatal sensory experience influence postnatal motor performance. In this series of studies, we used an avian model, the bobwhite quail, to evaluate the effects of prenatal temperature (study 1), prenatal movement (study 2), prenatal light duration (study 3), and prenatal light presentation pattern (study 4) on hatchability, growth and postnatal motor performance in 24hr quail neonates. In study 1, quail embryos were exposed to naturally occurring cool (36.9°C) or warm (38.1°C) temperatures for a brief 4-day period during early incubation. In study 2, quail embryos were exposed to increased or decreased egg turning experience during the second week of incubation. In study 3, quail embryos were exposed to 6hrs or 2hrs of crepuscular light stimulation during the final days of incubation. In study 4, quail embryos were exposed to either sporadic or crepuscular light patterns for either 2hrs or 6hrs durations during the final days of incubation. All studies, except for Study 4, were compared to control chicks who had received industry standard care throughout incubation, which included optimal temperature exposure of 37.5°C, movement every 2 hours, and light exposure for a 12hr on/off cycle. Motor performance, body mass and tarsometatarsus length (indicators of growth) were evaluated 24hrs after hatching. Cool thermal exposure delayed hatching, reduced body mass, and decreased motor performance. Warm thermal exposure delayed bone growth and increased fall frequency. Decreased movement exposure delayed hatching, reduced body mass, and delayed motor performance. Increased movement exposure delayed motor performance and reduced body mass but did not delay hatching. Crepuscular light exposure negatively influenced growth and decreased motor performance, but only delayed hatching in the 2hr crepuscular treatment. Lastly, results from study 4 demonstrated sporadic light presentation improved gait performance in 2hr exposed chicks and improved growth indicators in 6hr exposed chicks. This series of studies provide evidence that maternally regulated prenatal experience contributes to postnatal motor performance and highlights the importance of non-obvious stimulation for typical motor development