Fig. 2. Operantly conditioned semi-intact preparations demonstrated a reduction in total breathing following conditioning for learning and LTM. Conditioned and yoked control preparations were given a 20 min pre-observation period and a 20 min post observation period to assess total breathing time before and after their operant and yoked sessions, respectively. During the pre- and post-observation periods both conditioned and yoked preparations were allowed to breathe freely. The total breathing time of conditioned and yoked preparations during the pre-observation period did not significantly differ from each other (unpaired t-test=0.4451, P>0.05). Only the conditioned preparations demonstrated a significant reduction in total breathing time during the post observation period, which followed the LTM test (paired t-test=3.090, P=0.01). ^**P=0.01.