Performance under a Go/No-go task in rats selected for high and low impulsivity with a delay-discounting procedure

Abstract

Research with animals and humans suggests that impulsivity is both a determinant and a consequence of drug abuse. In the present study, rats screened for high (HiI) or low (LoI) impulsivity using a delay-discounting task were compared on a Go/No-go procedure for intravenous cocaine (0.4 mg/kg) or saccharin pellets (0.1%). An additional aim was to examine the effects of previous cocaine exposure on impulsive choice. Thus, following Go/No-go testing, HiI and LoI rats were reevaluated on delay discounting. The results indicated that HiI and LoI rats did not differ in Go (reinforced) responses or in the number of reinforcements earned under the cocaine or saccharin conditions. However, LoI rats made significantly more No-go (nonreinforced) responses under the cocaine versus the saccharin condition. After the Go/No-go procedure, cocaine-exposed LoI rats were more impulsive on the delay-discounting task for food, compared to LoI rats that were naive to cocaine; however, HiI rats did not differ on this measure. These results indicate that the effects of cocaine on measures of impulsivity may be determined by a preexisting level of impulsive behavior.

Dimensions of impulsivity among heavy drinkers, smokers, and heavy drinking smokers: Singular and combined effects

“…This is consistent with previous studies suggesting that higher delay reward discounting functions as a predisposing risk factor for alcohol and nicotine use (e.g., Anker, Zlebnik, Gliddon, & Carroll, 2009; Audrain-McGovern, et al, 2004; Perry, Nelson, Anderson, Morgan, & Carroll, 2007). It is plausible that those exhibiting higher delay reward discounting will not only be more likely to drink or smoke, but may also have a higher probability of concurrent use.…”

Acute nicotine increases both impulsive choice and behavioural disinhibition in rats

“…cocaine, amphetamine and alcohol) in comparable delayed reward tasks in both animals and humans (e.g. Anker et al 2009;Cardinal et al 2000;Evenden and Ryan 1996;Helms et al 2006;Reynolds et al 2006b;Stanis et al 2008).…”

“…Increasing evidence suggests that substances of abuse, and psychostimulants in particular, increase levels of impulsive choice and disinhibition in humans and laboratory animals (e.g. Anker et al 2009;Fillmore et al 2002;Harrison et al 1997;Helms et al 2006;Paine and Olmstead 2004;Stanis et al 2008;Van Gaalen et al 2006;but see De Wit et al 2002;Cardinal et al 2000;Fillmore et al 2006). Such findings suggest that psychostimulant abuse may itself lead to the heightened impulsivity often observed in chronic drug abusers (e.g.…”

Self-administered cocaine causes long-lasting increases in impulsive choice in a delay discounting task.

“…The results of this study are also consistent with previous work in rodents showing that chronic experimenter-administered cocaine can cause elevated impulsive choice, and in combination with our previous findings using experimenter-administered cocaine (Simon et al, 2007), they suggest that the route of administration is less of a critical factor than the amount of cocaine intake (Dandy & Gatch, 2009; Setlow et al, 2009). A recent paper by Anker, Zlebnik et al (2009) reported that prior cocaine self-administration experience caused an increase in impulsive choice in a delay discounting task when rats were tested immediately following cocaine cessation (this effect was specific to a subset of rats that displayed low levels of impulsive choice prior to cocaine experience). The present results extend these findings by showing that self-administered cocaine-induced elevations in impulsive choice can persist several months after cocaine cessation.…”