Midline and lateral field sound localization in the albino rat (Rattus norvegicus).

Six albino rats were used in tests of sound localization around midline and in left and right lateral field positions (i.e., 0 degree, -60 degrees, and +60 degrees azimuth). Each of the animals performed at high levels on the midline task but had great difficulty with tests in the left and right fields. Minimum audible angles for midline localization were obtained for 2 subjects and were estimated as 11.5 degrees and 13.5 degrees. Performance levels on the hemifield tests for each of the 6 animals, however, were too low to permit estimates of threshold even with speakers separated by 60 degrees. The differences between midline and lateral field sound localization are discussed.