PTPσ cued fear conditioning

<b>Fear Conditioning. </b>Male mice 4-7 months old were used for this experiment. This cohort of mice was older than the rest of the mice used in the other experiments. However, previous studies in the literature found no difference in the rodent performance of these age groups as compared to 2-3 months old animals in the cued fear conditioning paradigm (Stoehr and Wenk, 1995; Oler and Markus, 1998; Houston et al., 1999; Kaczorowski and Disterhoft, 2009) Mice were subjected to fear conditioning in a squared arena A (23 cm side, 35 cm height) with a metal grid on the floor and transparent acrylic glass walls, with continuous background white noise and 100 lux illumination. On day 1, the animals received five foot shocks (0.6 mA, 1 s) each preceded by a 30-s sound cue (latency to the first foot shock: 150 s, time between the last foot shock and the end of the trial: 30 s, inter-shock interval: 30-120 s, total session length: 8 min 45 s). On day 10, the mice were first placed in a new arena B (same size as arena A but with plastic grey floor and plastic black walls), and freezing in response to the sound cue was measured (cue retrieval). Two hours later, the mice were placed in the same context where fear conditioning took place (arena A), and freezing in response to the sound cue was measured (context + cue retrieval). Behavior was counted as freezing if the mouse was not moving for at least 3 s, and measurements were done automatically by TSE system software. <br>