The lack of an effect of antisense oligonucleotide treatment, given either 12 or 72 hr before, on behavior during the acquisition session. Rats were treated with sense oligonucleotides (SO), ASO, or vehicle and, after a 12 or 72 hr delay, subjected to the acquisition session of the conditioned fear protocol (Fig. 2). The behavior of the sense oligonucleotide-treated and vehicle-treated controls were not different and were combined into a single control group for graphic purposes only. Immobility was measured for each tone plus footshock pairing over a 1 min interval. There was no difference between the sense oligonucleotide- or ASO-treated groups at either 12 or 72 hr.