Reduction in buoyancy alters parameters of motility in E9 chick embryos.

Over the course of embryonic development, chick embryos express 3 different types of motility (I, II, III). Although neural pattern generators appear to control embryonic motility, the mechanisms responsible for the sequential emergence and/or transformations in these behaviors are not known. Given the early presence of functional sensory connections and substantial changes in movement dynamics associated with body growth in the fixed volume of an egg, it was hypothesized that changes in environmental constraints might contribute to shaping the transformations in motility. In this study, we tested the hypothesis that changes in buoyancy can alter parameters of motility in ovo at embryonic Day 9 (E9). Results demonstrate that attributes of Type I motility can be altered by a reduction in buoyancy. The possible contributions of the environment and experience to transformations in embryonic motor behavior are discussed.