Fig. 3: Fear conditioning in an acrylic box using optogenetic manipulation.

a, b Drawings (adapted from ref. ³³) and diagrams showing a transparent acrylic box surrounded by walls (a) and the conditioning paradigm (b, see “Methods”). c Each epoch alternated between offset time blocks (light orange zone) and onset time blocks (tones, light green zone). d, e During the sample sessions, individual Cre⁻ and Cre⁺ mice were placed in the box and learned an association between white walls/high tones and footshocks under flat photostimulation exposure (sky blue) as the CS⁺ (e) and black walls/low tones without footshocks as the CS⁻. f Bar plots showing the activity levels of Cre⁻ (blue) and Cre⁺ (orange) mice in the prestimulation period (2 s, e) and footshocks (2 s, e) during the sample session. g The recognition session for discriminating between the CS⁻ and CS⁺. h, i Plots showing the active time during the offset (light orange zone) and onset (light green zone) time blocks between the CS⁻ and CS⁺. The scale bar is 2 s in (e). Cre⁻ mice (n = 11, 3 females and 8 males, blue) and Cre⁺ mice (n = 11, 4 females and 7 males, orange) in (f, i). ^†††P < 0.005 (main effects and interactions using ANOVA), **P ≤ 0.01 and ***P < 0.005 (two-tailed Welch’s t test and two-tailed paired t test). Bar and line plots indicate means ± SEM. Circles in the graph represent individuals.