"Science Briefs" summarize the findings and implications of a recent study in basic science or clinical research. This brief reports on the study. This Brief summarizes the findings and implications of "Prenatal Exposure to Ultrasound Waves Impacts Neuronal Migration in Mice" (E. S. B. C. Ang, Jr.; V. Gluncic; A. Duque; M. E. Schafer; and P. Rakic). A study of mice exposed to ultrasound waves showed that the more intense the exposure, the more neurons will be misplaced in the brain and the more likely they are to develop atypical connections. [Title and Authors: Ang, E.S.B.C. Jr, Gluncic, V., Duque, A., Schafer, M.E. and Rakic, P. (2006). Prenatal Exposure to ultrasound waves impacts neuronal migration in mice. Proceedings of the National Academy of Science 103: 12903-12910.]