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. Author manuscript; available in PMC: 2016 Nov 3.
Published in final edited form as: Neuron. 2015 Sep 23;87(6):1317–1331. doi: 10.1016/j.neuron.2015.08.036

Fig. 6. Ocean cell input, but not Island cell input, is crucial for discriminatory encoding in CA3 for distinct context pairs but not for similar context pairs.

Fig. 6

(A) Labeling of c-Fos expressing cells in CA3 combined with optogenetic inhibition of Ocean cells.Bilateral injection of AAV2/5-CaMKIIα-eArchT3.0-eYFP or AAV2/5-CaMKIIα-eYFP (control group; not shown) in DG and AAV2/9-TRE-mCherry in CA3 with bilateral implantation of optic fibers into MEC of c-fos-tTA mice. (B) Labeling of c-Fos-expressed cells in CA3 combined with optogenetic inhibition of Island cells. Bilateral injections of AAV2/5-EF1α-DIOeArch3.0-eYFP in MEC and AAV2/9-TRE-mCherry in CA3, with bilateral implantation of optic fibers into MEC of double transgenic mice (c-fos-tTA mice crossed with Wfs1-Cre mice). (C) Example of c-Fos+ cells, mCherry+ cells, double+ cells, non-labeled cells. (D and H) To label the c-Fos expressed cells in Ocean-eYFP, Ocean-eArchT, and Island-eArch mice (A–B), animals were taken off Dox and exposed to Context A in order to label the cells activated by Context A with mCherry (red). Animals were then put back on Dox and exposed to distinct Context B 24 hours later as activated cells expressed c-Fos (green). Green light was illuminated in MEC during the animal’s exposure to Context A (D) or Context B (H). (E-G) Percentages of c-Fos+ cells in mCherry+ or mCherry− CA3 cells in the three groups of mice related to (D). Total number of mCherry+ cells studied were 254 (E), 122 (F), and 177 (G), and absolute number of mCherrycells studied were 1304 (E), 1432 (F), and 1164 (G) cells respectively. (I–K) Percentages of c-Fos+ cells in mCherry+ or mCherry− CA3 cells in the three groups of mice related to (H). Total number of mCherry+ cells studied were 194 (I), 181 (J), and 141 (K), and absolute number of mCherry- cells studied were 1000 (I), 1002 (J), and 710 (K) cells respectively. (L and O) To label the c-Fos expressed cells in Ocean-eArchT and Ocean-eYFP mice, animals (A) were taken off Dox and exposed to Context E in order to label the cells activated by Context E with mCherry (red). Animals were then put back on Dox and exposed to similar Context F 24 hours later so as to let activated cells express c-Fos (green). Green light was illuminated in MEC during the animal’s exposure to Context E (L) or Context F (O). (M and N) Percentages of c-Fos+ cells in mCherry+ or mCherry− CA3 cells in the two groups of mice related to (L). Total number of mCherry+ cells studied were 273 (M), and 155 (N), and absolute number of mCherry- cells studied were 1349 (M), and 1453 (N) cells respectively. (P and Q) Percentages of c-Fos+ cells in mCherry+ or mCherry− CA3 cells in the two groups of mice related to (O). Total number of mCherry+ cells studied were 319 (P), and 217 (Q), and absolute number of mCherry- cells studied were 1261 (P), and 1204 (Q) cells respectively. ***P< 0.001, **P< 0.01, *P< 0.05. Data are represented as mean±SEM. N indicates number of animals.