Figure 4.

Head-fixed behavior paradigm. A, Schematic drawing of the head-fixed behavior setup (top view). The setup consisted of three major components, a body holder, headpost holder, and the reward spouts. All three components could be moved relative to each other to allow the animal to assume a comfortable posture while in the setup, and to reach the spouts easily. Each spout could be moved independently between a retracted and a forward position by means of a gas piston. Animals could only lick the spouts when in the forward position. All spouts were mounted on a large translation stage to control their overall distance from the animal. In addition, the two peripheral spouts were mounted on two smaller translation stages to control the lateral distance between the spouts. This was necessary to make sure that animals could not activate more than one spout simultaneously. B, Side-view of the head-fixed behavior setup. C, Three-spout task design. A trial initiation cue was presented and the center spout was moved forward. When the ferret licked the center spout, a small reward was dispensed. Next, the center spout was retracted and stimulus presentation was triggered. The two choice spouts were moved forward. If the ferret licked the correct spout first, the incorrect spout was retracted, the stimulus removed, and the ferret received a large water reward. If the ferret contacted the incorrect spout first, it was also retracted. The ferret then had to contact the correct spout (which remained in position) to end the trial and receive a much smaller reward.