THC and vehicle (e.g., drug, drug, vehicle, vehicle). For both studies, daily 15 min training sessions were held Monday-Friday until the mice consistently met two criteria: (1) the first completed FR10 was on the correct manipulandum and (2) ≥ 80% of the total responding occurred on the correct manipulandum. Due to the probable floor effect engendered by the low response rates in Experiment 1, Experiment 2 included the additional criterion of response rates consistently ≥ 0.16 responses/s. When the criteria were met in each experiment, acquisition of the discrimination was established and substitution testing began.
