Fig. 8.

Changes in neural activity during odor sampling and behavioral measures of learning during initial training. Contrast in activity of neurons in OFC (A) and in ABL (B) during odor sampling in the early (white bars) and late (black bars) phases of precriterion training and during postcriterion performance (gray bars). The activity contrast was calculated as the difference in firing rate during sampling of positive and negative odors divided by the sum of those rates, expressed with reference to the preferred odor during postcriterion trials. Activity between trials was used to calculate a baseline contrast of 0.04 for OFC and −0.01 for ABL. ANOVA with post hoc testing showed that selectivity in OFC differed significantly from baseline only during postcriterion training, whereas selectivity in ABL differed in the late and postcriterion phases (*p < 0.05).C, Go, no-go performance in the early and late precriterion and the postcriterion phases (chance, 50%).D, Changes in differential response latency in the early and late precriterion and the postcriterion phases. The latency difference increased significantly (F_(2,156) = 6.69; p= 0.0016) from the early to the late phase of precriterion training (*p < 0.05). Latency to respond on positive trials remained near 350 msec across training; thus, the increase was primarily attributable to increases in latency to respond on negative trials. The increase in selectivity in OFC neurons postcriterion (A) coincided with improved accuracy in go, no-go performance (C). Changes in selectivity in ABL neurons (B) coincided more closely with changes in the differential response latency across the training phases (D). A andB were adapted from Schoenbaum et al. (1999).