Figure 4.

Effects of the CHT inhibitor VU600122 on pavlovian conditioned approach behavior toward a lever (CS) versus the location of food delivery (food cup; n = 49; n = 25 treated with VU600122; n = 24 treated with vehicle). Behavior was measured over five training sessions to determine lever- and food cup-directed behavior after administration. a, Drug or vehicle was given before sessions 2–5. Data from session 1, and after the administration of vehicle, were used to exclude rats that exhibited an early trend for sign-tracking behavior, to allow for a more “aggressive” test of the hypothesis that VU600122 fosters sign-tracking. b–f, The plots depict mean ± SEM for food cup or magazine (mgz.) contacts evoked by the CS (b), number of lever contacts (c), number of non-CS food magazine entries (d), latency to first lever contact after CS presentation (e), and latency to the first food magazine entry after CS presentation (f). Compared with the effects of vehicle, administration of VU600122 facilitated lever-oriented behavior and reduced CS-evoked magazine-oriented behavior (for main effects of treatment and interactions, see Results; multiple comparisons indicated in c and f were based on significant interactions between the effects of VU600122 and session; see Results).