Fig. 4.
Effects of intermittent intravenous cocaine self-administration in high-impulsive rats (n = 8) and non-impulsive rats (n = 8) on sustained visual attention on the 5-CSRT task. (A) Rats were withdrawn from intravenous cocaine self-administration on four occasions and tested 24 hours later for 7 consecutive days on the 5-CSRT task. ShA, tested after short access to cocaine over 5 days, when rats received 50 cocaine infusions over 5 hours; LgA-1, tested after long access to cocaine, when the daily number of cocaine infusions increased to 150 and the session duration to 8 hours; LgA-2, tested after a second long-access exposure to cocaine; LgA-3, tested after a third long-access exposure to cocaine. ANOVA of premature responses revealed significant group × cycle [F(3,42) = 7.86, P = 0.023] and group × cycle × session [F(18,252) = 4.29, P < 0.001] interactions. Subsequent analyses revealed that premature responding was higher in high-impulsive rats as compared to non-impulsive rats during the ShA cycle [group: F(1,14) = 20.58, P < 0.001] but not during subsequent LgA-1 [F(1,14) = 0.62, P = 0.44], LgA-2 [F(1,14) = 3.82, P = 0.071], and LgA-3 [F(1,14) = 0.51, P = 0.49] cycles. There were no significant differences between non-impulsive and high-impulsive rats with respect to (B) attentional accuracy, (C) omissions, and (D) correct response latency (F < 1.44, P > 0.24 for all comparisons). Black circles, high-impulsive rats; white circles, non-impulsive rats.