Development of a useful technique for analyzing behavioral teratologic data

Two measures of postnatal development are described in this paper: the PAC50 and AD50. These measures proved to be more sensitive than the use of means in the evaluation of three radiation studies involving postnatal developmental evaluation. PAC50 is the percent of achievement of a goal by litters or offspring in an experimental group at the age when 50% of the control litters or offspring attain that goal. AD50 is the age (acquisition day) at which 50% of the litters or offspring in each group attain a specified developmental goal. This methodology is a useful technique for analyzing selected behavioral data following in utero X-irradiation and may prove to be a sensitive means of determining postnatal alteration due to prenatal exposure to a variety of suspect agents.