Fig. 4.

IC neurons reciprocally connected with the BLA are preferentially activated by CTA memory retrieval. a Experimental schema (top panel). CTB and AAV₁-hSyn-Cre injection into the BLA and AAV₁-Ef1a-DIO EYFP injection into the IC (bottom left panel). Representative image showing coronal section of the IC with CTB (red) and YFP (green) labeled cells. Scale bars = 1000 um (bottom middle). Magnified representative image showing double-positive (yellow, reciprocally connected), YFP+/CTB- (BLA-to-IC only) and YFP−/CTB+ (IC-to-BLA only) IC neurons (bottom right). Scale bar = 20 um. b Data showing the mean quantity of saccharine solution (orange column) and water (blue column) consumed in the retrieval test (N = 5 animals). c Representative image showing expression of c-fos (cyan) following memory retrieval test, CTB (red) and YFP (green). Scale bar = 100 um. d Probability of occurrence of cells expressing c-fos after retrieval test over double-positive (yellow column), YFP+ ∩ CTB- (red column) and YFP- ∩ CTB+ (green column) cells in the IC. Data are represented as mean ± SEM; **p < 0.01 and ***p < 0.001