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. 2015 Feb 18;9:9. doi: 10.3389/fnint.2015.00009

FIGURE 1.

FIGURE 1

Experimental setup (A) and trial (B) and session (C) types for an attention-shift task. (A) Experimental setup. Rats were prepared for chronic recording by forming receptacles of dental cement to accept artificial earbars. Electrodes were implanted in the lateral hypothalamic area for intracranial self-stimulation (ICSS) of the medial forebrain bundle. The rat was trained to lick when the spout was automatically placed close to its mouth. Auditory and visual conditioned stimuli (CSs) were presented by a speaker in front of its head and a light in front of each eye, respectively. (B) Trial types. In each trial, the CS appeared for 1 s, followed by spout protrusion close to the mouth for 2 s. In the reward (a) but not non-reward (b) trials, rats could obtain an ICSS reward if the rats licked the spout. (C) Session types. The task included five sessions. In session 1, right light (frequent stimulus) was sequentially presented, and when the left light, an infrequent stimulus, appeared, the rat could acquire reward if it licked the spout. In session 2, left light (frequent stimulus) was sequentially presented, and when the right light (infrequent stimulus) appeared, the rat could acquire reward if it licked the spout. In sessions 3 and 4, right and left lights (frequent stimuli) were similarly presented, respectively. However, the infrequent stimuli appeared with the frequent stimuli. Therefore, in sessions 3 and 4, the rat must disengage attention from the frequent stimulus. Arrows show attention disengagement and subsequent direction of attentional shift. Lights and speaker with the red-colored lines indicate that these apparatuses are turned on. In session 5, tone (frequent stimulus) was sequentially presented, and when both right and left lights (infrequent stimuli) were simultaneously presented, the rat could acquire reward if it licked the spout. Note that the infrequent stimuli in session 5 were the same as those in sessions 3 and 4, but attentional disengagement was not required in session 5. R1–R5, reward trials in sessions 1–5; N1–N5, non-reward trials in sessions 1–5.