Fig. 1

Association between optogenetic stimulation and foot-shock. a Expression of oChIEF-tdTomato in the AC and the MGN (left), as well as the LA (right) 4 weeks after viral injection. Blue arrow indicates position of implanted optic fiber. Scale bars: 500 μm. b Behavioral paradigms of associative fear training (left) and recall test (right). c. Fear training using oMFS paired or unpaired with foot-shocks (repeated every 3 min for 5 times). Fear response was assessed in the lever-pressing box 24 h later with OTS. d Normalized number of lever presses (shown in 1-min bin) from lever-pressing tests 24 h after fear training. Lever pressing was significantly inhibited by OTS (blue area) in the paired group (n = 4) but not in the unpaired group (n = 4). * indicates P < 0.05; one-way repeated ANOVA followed by Tukey’s multiple comparison test. All error bars in this and subsequent figures are SEM. e Mean normalized number of lever presses during the 2 min of the OTS. Significant reduction in lever pressing was found in paired group (n = 4) compared with the unpaired group (n = 4). ** indicates P < 0.01; Student’s t-test. f-h Similar to c-e, but for fear training with oHFS followed by a 3-s foot-shock with a delay of 5 min, 1 h or 3 h. Significant reduction in lever pressing was found in the 5-min group (n = 6) and 1-h group (n = 7), but not in the oHFS alone group (n = 6) or 3-h group (n = 6) or vector-1-h control group (n = 6). * indicates P < 0.05; *** indicates P < 0.001; one-way repeated ANOVA (g) and one-way ANOVA (h) followed by Tukey’s multiple comparison test. i-k Similar to f-h, but for fear training with oHFS 5 min and 1 h after the foot-shock. Significant reduction in lever pressing was found in the 5-min group (n = 7) but not in the 1-h group (n = 6). The same data for the oHFS alone group in g-h is shown here again as a control. *** indicates P < 0.001; one-way repeated ANOVA (j) and one-way ANOVA (k) followed by Tukey’s multiple comparison test