Principal component analysis yielding 3 rotated components <i>(N = 100)</i>.

<p>Factor loadings >0.5 as significant.</p>a<p>k values were obtained by a hyperbolic decay function and log transformed.</p>b<p>IMT and DMT scores were calculated as the ratio of commission errors to correct detections.</p><p> <i>DDT: Delay Discounting Task, IMT: Immediate Memory Task, DMT: Delayed Memory Task, SSRT: Stop Signal Reaction Time, BIS-11: Barratt Impulsiveness Scale.</i></p

Correlation between impulsive choice and action after pharmacological manipulations in rats.

<p>In rats (n = 22), there was no correlation between the effects of (A) amphetamine (0.5 mg/kg, r = .22) and (B) atomoxetine (1 mg/kg, r = .21) on the two impulsivity measures: the Δ indifference point ( = drug challenge minus vehicle) of the delayed reward task and the Δ premature responses ( = drug challenge minus vehicle) in the 5-choice serial reaction time task did not correlate.</p

Correlation between impulsive choice and action in humans.

<p>In humans (n = 100), there was no correlation between impulsive choice (log DDT k value) and impulsive action measured as the ratio of commission errors to correct detections in (A) IMT (r = .11) and (B) DMT (r = .16). Within the IMT/DMT (C) there was a correlation between the ratio of commission errors to correct detections in the IMT and DMT (r = .64).</p

Pharmacological manipulation of impulsive choice and action in rats.

<p>In rats (n = 22), the preference for the large reward in the DRT decreased with increasing delays (A) and amphetamine (0.5 mg/kg) decreased impulsive choice in rats, whereas atomoxetine (1 mg/kg) increased impulsive choice. In the 5-CSRTT (B), amphetamine increased premature responding, whereas atomoxetine decreased the number of premature responses. *p<0.05, **p<0.001 compared to vehicle.</p

Correlation between impulsive choice and action in rats.

<p>In rats (n = 22), there was no correlation between impulsive action, based on premature responses in the 5-CSRTT, and impulsive choice, based on (A) the indifference point (r = −.22) or (B) the log k-value (r = .09) in the DRT. Within the 5-CSRTT (C) there was a correlation (r = .77) between impulsive action with a standard inter trial interval (ITI 5 s) and lengthened inter trial interval (ITI 7 s).</p