Increase of [Ca
]i by uncaging of NP-EGTA-AM triggers long-term memory formation. Retention performances, as the percentage of specific response (% SR, % individuals responding to the conditioned stimulus and not to the new odor), following an injection of NP-EGTA-AM (20 mM) or saline solution 1 h before one-trial conditioning. The SR of the NP-EGTA-AM (n = 64) group was significantly higher than the control (n = 72) at 72 h (χ2 = 4.53, P = 0.033). However, at 3 h (Control: n = 66; NP-EGTA-AM: n = 65) and at 24 h (Control: n = 102; NP-EGTA-AM: n = 111) the SR were no significantly different (respectively: χ2 = 1.1, P = 0.30; χ2 = 0.3, P = 0.56). (*: P < 0.05, NS: non-significant).