Figure 3.

BF^GAD2+ neuron activation disrupts conditioned fear expression but not learning. (a) Design for test of fear memory expression. Following conditioning in context A, animals were placed into a distinct arena (context B) and presented with 4 CS trials, two of which coincided with photostimulation, in a counterbalanced fashion. (b) Freezing levels during final two CS trials of conditioning. (c) CS-evoked freezing during laser^ON vs. laser^OFF CS trials. ChR2, Wilcoxon signed rank test, W = − 66, **p < 0.01. eYFP, paired t-test, t₁₀ = 2.40, *p < 0.05. ChR2, n = 12; eYFP, n = 11. (d) Difference in freezing during laser^ON vs. laser^OFF CS trials. ChR2, n = 12; eYFP, n = 11. (e) Fictive eating during laser^ON vs. laser^OFF CS trials. ChR2, Wilcoxon signed rank test, W = 45, **p < 0.01. (f) Design for test of fear learning. During fear conditioning (context A) mice were presented with 6 CS-US pairings that coincided with laser stimulation, and on the following day were tested for long-term memory by exposure to 2 CS trials in the absence of laser stimulation in a context distinct from the training arena (context B). (g) Freezing levels across all CS trials of conditioning. Mann–Whitney test, U = 4, *p < 0.05. ChR2, n = 7; eYFP, n = 6. (h) Fictive eating during CS trials. Mann–Whitney test, U = 6, *p < 0.05. ChR2, n = 7; eYFP, n = 6. (i) Freezing levels during inter-CS intervals. ChR2, n = 7; eYFP, n = 6. (j) CS-evoked freezing during the retrieval test. ChR2, n = 7; eYFP, n = 6. (k) Design for test of anxiety-like behavior using the elevated plus maze (EPM). (l) Percent time spent in open arms during laser^ON vs. laser^OFF epochs. ChR2, Wilcoxon signed rank test, W = − 89, **p < 0.01. ChR2, n = 15; eYFP, n = 15. Schematics (a,f,k) were created using BioRender.com and PowerPoint.