Pavlovian conditioned approach.

Alcohol-preferring rats (P, closed squares) and alcohol-non-preferring rats (NP, open circles). Data are means ± SE of probability of lever press (a), probability of nose-poke (b), latency of lever press (c) response bias [(number of lever presses-number of magazine nose-pokes)/(number of lever presses + number of magazine nose-pokes)] (d), and number of nose-pokes from trials 1 to 25 during the first session (e). Statistics: repeated measures ANOVA for each line were performed followed by paired samples t tests comparing each of the sessions with session 1 for graphs A-D, and comparing trial 25 vs trial 1 in graph E. Results: Probability of lever press: P rats did not significantly increase their probability of lever press across sessions (lack of session effect (F (4,56) = 1.662, n.s), but P rats showed an increase in the probability of lever press across sessions (F (4,48) = 6.112, p (PDF)