Table 1 Effects of amphetamine, GBR12909, atomoxetine and citalopram on behavioral performance (accuracy, omissions, prema- ture and perseverative responses, response latency) under baseline conditions (visual stimulus presented 5 s after trial initiation) in the 5- Psychopharmacology (2012) 219:313–326 CSRTT. In total, n=16 animals were included in the analysis. *p<0.05 and **p<0.01 compared to vehicle treatment (paired samples t-test). All data are expressed as mean±SEM Correct responses Errors of omission Premature responses Perseverative responses Response latency (s) 90.8±1.4 85.2±2.2* 82.9±2.3* 79.1±2.3* 90.7±1.1 91.2±1.2 89.0±1.4 85.3±2.3** 91.0±1.5 94.6±1.4 94.3±1.0 94.5 ±1.6 91.7±1.0 91.7±1.3 92.2±1.2 92.5±1.2 17.9±1.6 12.4±1.3* 16.2±2.3 32.5±5.2** 14.6±2.1 15.8±2.7 11.6±1.8 10.2±1.9 18.4±2.2 25.8±2.5* 33.4 ±3.0** 44.3±2.8** 12.8±2.1 15.8±2.6 16.4±2.6 16.6±2.2 6.3±1.0 18.4±4.4** 24.0±4.1** 36.3±6.0** 5.3±0.8 4.8±0.7 8.9±2.4 29.9±8.2** 6.4±1.5 3.2±1.2 3.5±0.9 3.5±0.9 5.1±0.8 4.8±0.9 2.6 ±0.4* 3.1±0.7 13.8±2.4 23.7±4.9* 23.8±5.7* 29.2±6.6* 6.7±1.1 5.9±0.7 7.9±1.6 21.4±4.9** 14.6±4.2 11.0±2.3 10.9±1.9 10.2±2.4 7.0±1.7 7.1±1.1 4.1±1.1 7.4±1.5 0.71±0.03 0.66±0.02 0.6±0.02* 0.71±0.03 0.67±0.02 0.67±0.02 0.64±0.02* 0.61±0.02** 0.73±0.03 0.81±0.04** 0.84±0.04** 0.96±0.04** 0.66±0.02 0.68±0.02 0.69±0.02* 0.70±0.02* 318 Amphetamine Veh 0.25 mg/kg 0.5 mg/kg 1.0 mg/kg GBR12909 Veh 2.5 mg/kg 5.0 mg/kg 10.0 mg/kg Atomoxetine Veh 0.3 mg/kg 1.0 mg/kg 3.0 mg/kg Citalopram Veh 0.3 mg/kg 1.0 mg/kg 3.0 mg/kg observed on errors of omission [df = 15, t = −0.65, NS and df = 14, t = 0.66, NS]. Atomoxetine (3 mg/kg) reduced premature and persev- erative responding under long ITI conditions (Fig. 2c) [df = 15, t = 6.0, p < 0.001 and df = 15, t = 4.47, p < 0.001, respec- tively]. Additional comparisons revealed that all other parameters of 5-CSRTT were enhanced by atomoxetine under these conditions (Fig. 2c) [correct responses: df = 15, t = −2.97, p = 0.01; omissions: df = 15, t = −2.33 p < 0.05; response latency: df = 15, t = −2.26, p < 0.05]. Premature and perseverative responses were both re- duced by citalopram (1 mg/kg) pretreatment under long ITI conditions (Fig. 2d) [premature responses: df = 15, t = 4.28, p = 0.001, perseverative responses: df = 15, t = 2.49, p < 0.05]. Under these conditions, citalopram did not affect accuracy, errors of omission and response latency [correct responses: df = 15, t = −0.22, NS, omissions: df = 15, t = −0.19, NS and response latency: df = 15, t = 1.26, NS]. Effect of amphetamine and monoamine reuptake inhibitors on impulsive choice in the DRT Overall, animals showed a delay-dependent decline in their choice behavior for the large, delayed reward [vehicle, delay: F(4,48) = 31.49, p < 0.001]. Amphetamine significantly enhanced the preference for the large delayed reward [dose: F(3,36)=3.11, p<0.05; dose×delay: F(12,144)=1.33, NS], and post-hoc analysis revealed that this effect was significant for all doses of amphetamine at the 40-s delay and for 0.5 and 1 mg/kg amphetamine at a delay of 60 s (Fig. 3a). The selective DA reuptake inhibitor GBR12909 also increased the preference for the larger delayed reward [dose: F(3,39) = 11.07, p < 0.001; dose × delay: F(12,156) = 2.29, p = 0.01]. Post-hoc analysis of the data showed a significant effect of 10 mg/kg of GBR12909 on all delays, i.e., 10, 20, 40 and 60 s (Fig. 3b). At a dose of 5 mg/kg, GBR12909 resulted in an increased preference for the large reward at the delay of 10 and 20 s (Fig. 3b). The selective reuptake inhibitor atomoxetine did not alter choice behavior in the DRT at any delay [dose: F(3,39)= 0.31, NS; dose×delay: F(12,156)=1.64, NS]. The selective 5-HT reuptake inhibitor citalopram also did not affect choice behavior in the DRT (Fig. 3d) [dose: F(3,39)= 1.27, NS; dose×delay: F(12,156)=1.11, NS]. Discussion In order to advance our understanding of the role of monoamine neurotransmission in impulse control, the