Effects of cocaine and d-amphetamine on sustained and selective attention in rats.
The effects of cocaine and d-amphetamine were compared in two attention-loading tasks. Cued by the position of a light, rats were food-reinforced for pressing one of two levers in a 2-choice, discrete-trial procedure. In the "sustained attention" task, the cue light was illuminated for a brief period (1.8 sec or less) at the beginning of each trial. In the "selective attention" task, the cue light remained on until a level press, while a blinking light over the incorrect lever served as a distractor. In the sustained attention task, low doses of d-amphetamine (0.25 mg/kg SC) and cocaine (2.5 mg/kg SC) enhanced accuracy; some doses of d-amphetamine (0.75 mg/kg SC) and cocaine (1.25 and 2.5 mg/kg SC) also reduced choice latencies. In the selective attention task, the lower doses of these drugs had no effect on accuracy, the highest dose of d-amphetamine (1.25 mg/kg SC) disrupted accuracy, and all doses of the drugs reduced choice latencies. The time to retrieve food was increased in a dose-dependent fashion by both drugs in both tasks. These results indicate that, other than differences in potency, cocaine and d-amphetamine induce similar behavioral effects in attention-loading tasks, with improvement or interference with performance dependent on the dose and the type of attention demanded of the task.
Grilly
D M
DM
Psychology Department, Cleveland State University, OH 44115.
Gowans
G C
GC
McCann
D S
DS
Grogan
T W
TW
D000818:Animals; D001288:Attention / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D003042:Cocaine; D003913:Dextroamphetamine