Figure 2. Spontaneous versus rewarded detection of low concentration odorants.
A. Spontaneous detection. Rats habituated to mineral oil only investigated odorants at 10−2, but not 10−4 or 10−5 Pa significantly more than the last presentation of mineral oil. Asterisks indicate a significant increase as compared to the last habituation trial. B. When motivated to find a reward in low concentration odorants, rats performed equally well on all concentrations used, showing that they are capable of responding to these low concentration odorants. The graphs show the average percent of investigation time as compared to the first habituation trial for all three concentrations (A) as well as the average percentage of correct choices made in the reward motivated detection task for all three concentrations (B).