Figure 2. Task Design.

A. World-centered task in which subjects approached the center of a speaker ring to initiate presentation of a 250 ms broadband noise burst from a speaker either at the North (N) or South (S) of the arena, or later from probe speakers around the remainder of the arena (gray) by responding at East (E) or West (W) response ports. Arrows show the position of correct responses, which remained constant as the central platform was rotated. F-numbers (F1701 etc.) refer to ferrets trained in the North-South discrimination. B. Dissociation of speaker angle relative to the head and speaker angle in the world as the platform angle was rotated at 30° intervals. In addition to test sounds, probe sounds were also presented from untrained speaker locations on a random subset (10%) of trials. C. Variant of the task for an additional ferret (F1902) in which we altered the world-centered locations to be associated with each response. D. Head-centered task in which subjects discriminate 250 ms broadband noise bursts from a speaker either at the Front (F) or Back (B) of the head, by visiting response ports either to the left (L) or right (R) of the head. Arrows show the direction for correct responses. E. Dissociation of speaker angles in head and world-centered space as platform angle was rotated. F. Variant of the task in which we altered the head-centered locations associated with each response for one ferret.