Fig. 2.

Floor plan (A) and side view (B) of the testing arena used to measure vertical localization. Animals were trained to discriminate between two broadband sound sources located on the midsagittal plane and differing only in their vertical locations. The testing chamber was circular in shape (radius 75 cm). To initiate a trial the ferret stood on the central platform and licked the start spout. This triggered the presentation of a noise burst from one of 2 speakers located on a curved rail outside the wire-mesh dome that enclosed the chamber. Response spouts were located at +90 and –90°.