Setting up the dual-event inhibitory avoidance task in mice. (A) In group-housed animals (n = 27), 48 h retention latencies did not significantly differ across the three test contexts. However, group-housing was associated with marked freezing behavior of mice that were tested as the last ones of their cage (n = 6, depicted in red). Consequently, they did not cross to the dark compartment in several or all of the test contexts. Therefore, we switched to single-housing conditions for the next experiment. (B) Training of single-housed mice (n = 10), using the same experimental parameters, induced memory specificity on a 48 h retention test, reflected by longer retention latencies in the Shock box compared to those in both the Non-Shock box (NS) and Novel box (N). Task parameters changed relative to the prior task conditions are depicted in bold. Data represent mean + SEM. Dots indicate individual data points. (**) P < 0.01 different from Shock box.
