Amphetamine and the adenosine A(2A) antagonist KW-6002 enhance the effects of conditional temporal probability of a stimulus in rats.
As the length of foreperiod preceding an imperative signal increases, reaction time decreases and anticipatory (prior to the signal) responding increases. The authors designed a task to dissociate the effect of elapsing time in the foreperiod and conditional temporal probability of the imperative stimulus. The effects of 2 drugs--amphetamine and KW-6002--known to enhance the effect of foreperiod were compared. Three groups of rats were trained to respond to an auditory signal presented at 1 of 3 foreperiods, unpredictable from trial to trial. The length of preparation time was different for each group, but conditional temporal probability was the same. Reaction times were faster as a function of increased preparation time, whereas anticipatory responses were strongly modulated by conditional probability. Both amphetamine and KW-6002 speeded reaction times and increased anticipatory responding. The pattern of behavior was consistent with the suggestion that they enhanced the motor preparatory effects of conditional probability rather than speeded a timing process. The authors concluded that preparation time and expectancy (conditional temporal probability of an imperative signal) have differential effects on performance and that amphetamine and KW-6002 enhance the effect of expectancy.
O'Neill
Martin
M
School of Psychology, University of St. Andrews, St. Andrews, Scotland, United Kingdom.
Brown
Verity J
VJ
D058917:Adenosine A2 Receptor Antagonists; D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D008297:Male; D011336:Probability; D011687:Purines / Q000494:pharmacology*; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D013997:Time Factors
D058917:Adenosine A2 Receptor Antagonists; D000697:Central Nervous System Stimulants; D011687:Purines; C111599:istradefylline; D000661:Amphetamine