Figure 3.

Optical stimulation at 11 Hz results in decreased exploration of novel images. As for Figure 2, paradigms are shown above the bar graphs. Stimulation was paired with exploration of image(s) in the choice period (the two right panels in each set of four). Control conditions (CTL) are above the images and experimental conditions (EXP) are below. An empty box indicates no stimulation (NS). For CTL, the laser was connected and operated exactly as in the experimental condition, but light was physically blocked from entering the fiber. For illustration, left and right choice images represent familiar/novel images (a, b) or novel-paired/novel images (c, d), respectively. Therefore, in all panels, the image and stimulation condition in which greater exploration was expected is shown on the right such that DR = (R − L)/(R + L). a, In CTL, rats (n = 7) discriminated normally. In EXP, when optical stimulation at 11 Hz was paired with looking at the novel image, rats explored the familiar image and the novel paired image equally. b, Replication of a (n = 8). c, In CTL, rats (n = 6) explore the two novel images equally. In EXP, stimulation at 11 Hz decreased exploration of the paired novel image (n = 6). d, Replications of c (n = 8). Data are means ± normalized SEM. *p < 0.05; +p < 0.10 (rANOVA); #p < 0.05 (t test), significant difference from zero.