Figure 3.

Turn rate. Turn rate as function of bearing angle to the odor source (A–C), and summarized by bearing angles toward (A′–C′) or away from (A″–C″) the odor source. (A–A″) Innate behavior. In experimentally naïve animals, increasing the concentration of the odor source decreased turn rate when heading toward the odor source (A′) (P < 0.05, H = 41.8, df = 4, KW), and increased turn rate when heading away from it (A″) (P < 0.05, H = 23.4, df = 4, KW). When heading toward the odor source (A′), turn rate for all odor concentrations differ from the no-odor condition (P < 0.05/4, U = 516, 351, 357, 225, MWU). When heading away from the source (A″), turn rates differ from control only for the highest concentration (P < 0.05/4, U = 315, MWU), but not for lower concentrations (P > 0.05/4, U = 637, 674, 612, MWU). (B–B″) Learned behavior. As compared with baseline, paired and unpaired training modulate turn rate in opposing ways; these effects, as in the case of innate behavior, differ in sign across bearing angles: when heading toward the odor source (B′) (P < 0.05, H = 26.3, df = 2, KW), turn rates after paired training are lower than after unpaired training (P < 0.05/3, U = 304, MWU) and lower than baseline (P < 0.05/3: U = 1152, MWU); after unpaired training turn rates are higher than baseline (P < 0.05/3: U = 938, MWU). When heading away from the odor source (B″), the results are inverse (P < 0.05, H = 6.9, df = 2, KW), that is turn rates after paired training are higher than after unpaired training (P < 0.05/3, U = 544, MWU); relative to baseline, turn rates tend to be higher after paired and lower after unpaired training (P > 0.05/3: U = 1224, 1449, MWU). (C–C″) In experimentally naïve animals, turn rate is generally increased in the presence of the reward, regardless of bearing angle (P < 0.05, U = 547, 529, MWU). For other details, see legend of Figure 1.