Figure 1. Texture Discrimination Tasks.

Trials sketched from camera images.

(A) The 1-arm task. (i) The rat perched on the edge of the platform and extended to touch the rough texture (gray rectangle) with its whiskers. (ii) Having identified the texture, the rat turned to the right drinking spout and received a water reward.

(B) The 3-arm task. (i) The rat began by crossing from the start arm to the central platform, (ii) touched the smooth-textured discriminandum with its whiskers, (iii) rejected the first texture and proceeded to touch the rough-textured discriminandum, and (iv) crossed the gap to collect a water reward at the distant part of the arm.