(A) Experimental schedule for AAV injection, RS exposure, auditory-cued fear conditioning, and optical LTP or LTD induction. (B) Representative fluorescence image of areas expressing AAV-oChIEF-tdTomato 4 weeks after virus injection in the medial geniculate nucleus (MGN) and auditory cortex (AC). LA, lateral nucleus of the amygdala. (C) Floxed GR mice (n = 8) that received immediate optical LTP after the first auditory-cued fear memory test (Test 1) exhibited significantly increased freezing levels in the second auditory-cued fear memory test (Test 2). (D) LAGRKO mice (n = 8) that received optical LTP stimulation exhibited the same freezing levels in Tests 1 and 2. (E) LAGRKO mice (n = 8) that received LTD stimulation immediately after Test 1 exhibited significantly lower freezing levels in Test 2 than in Test 1. Graphs show the freezing rate during the first 1 min of tone presentation at Tests 1 and 2. (F, G) A plot of the average of field EPSP slopes (normalized to the period before optical stimulation) before and after delivering an optical LTP (Floxed GR, n = 4, before LTP, 100 ± 0.8%, after LTP, 148.9 ± 3.2%; LAGRKO, n = 4, before LTP, 100 ± 0.6%, after LTP, 149.3 ± 2.8%) or LTD (Floxed GR, n = 4, before LTD, 100 ± 0.5%, after LTD, 77.4 ± 0.8%; LAGRKO, n = 4, before LTD, 100 ± 0.6%, after LTD, 76.7 ± 0.8%). Data are presented as mean ± S. E. M. *p<0.05.