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| Int'l Symposium - Effects of Amphetamine on Timing |
| Saturday, May 28, 2005 |
| 2:30 PM–3:50 PM |
| Lake Ontario (8th floor) |
| Area: BPH; Domain: Basic Research |
| Chair: Amy Odum (Utah State University) |
| Discussant: Angelo Santi (Wilfrid Laurier University) |
| Abstract: This symposium gathers recent data on the effects of amphetamine on temporally organized behavior. McClure and colleagues will present data on the effects of amphetamine on matching-to-sample of durations. Ward and colleagues will report the effects of amphetamine on behavior maintained by two different temporal discrimination procedures, one in which the correct response location is predictable before the sample presentation and one in which it is not. Saulsgiver and colleagues will present data on the effects of amphetamine on behavior maintained by a multiple schedule of differential reinforcement of low rate (DRL) schedules. In one component, the DRL is continuous, and in the other, the DRL is presented in discrete trials, allowing examination of the effects of amphetamine on behavior under different types of stimulus control. Discussion will follow by Santi. |
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| Effects of Amphetamine on Duration Discrimination in the Pigeon |
| ERIN A. MCCLURE (University of Florida), Kathryn A. Saulsgiver (University of Florida), Clive D. L. Wynne (University of Florida) |
| Abstract: Two experiments used a Matching to Sample of Durations procedure to examine changes in temporal discrimination evoked by amphetamine. The sigmoid functions relating percent of choices of the key reinforced after long duration stimuli to the duration of stimulus presented were fit by cumulative normal function. As well as a parameter to assess left/right positioning of the sigmoid curves (which indexes temporal perception), this function also estimates the range and slope of the curve (measures of stimulus control). Results showed that, contrary to many published reports, amphetamine had no effect on the left/right positioning of the sigmoid curve. There was, however, an effect of amphetamine on stimulus control, as is shown by the general flattening of the psychophysical function. |
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| Effects of D-Amphetamine on Temporal Discrimination: Position Versus Symbolic Matching-to-Sample Procedures |
| RYAN D. WARD (Utah State University), Robert R. Packer (Utah State University), Amy Odum (Utah State University) |
| Abstract: Recent experiments examining the effects of drugs on behavior maintained by temporal discrimination procedures have led to discrepant results. Current research has been unable to identify all of the variables responsible for these discrepancies. One possibility is that the effects of drugs on behavior during temporal discrimination components may differ depending on whether the correct response location is predictable before the sample presentation, or whether the procedure is truly retrospective. To examine this possibility, we exposed pigeons to a multiple schedule procedure composed of a position timing component, in which responses to one key are reinforced following shorter samples, and responses to the other key are reinforced following longer samples, and a symbolic matching-to-sample component. This component differs from the position component in that the correct key location cannot be determined until after the sample has been presented. Following stability on this procedure, we examined the effects of a range of doses of d-amphetamine on performance during the two temporal discrimination components. |
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| Effects of D-Amphetamine on a Multiple Continuous DRL 8-Sec Discrete DRL 8-Sec Schedule |
| KATHRYN A. SAULSGIVER (University of Florida), Erin A. McClure (University of Florida), Clive D. L. Wynne (University of Florida) |
| Abstract: Animals’ sensitivity to the passage of time has been conceptualized as a behavior that is controlled by internal stimuli. Due to this internal control it has been suggested that this type of behavior is more sensitive to drug effects than behavior controlled by external stimuli (Laties, 1966). The present study examined the effects of d-amphetamine on a multiple continuous DRL 8-sec discrete-trial DRL 8-sec schedule. This schedule offers subjects the opportunity to time from two types of stimulus: 1) an external stimulus (trial onset) and 2) the subjects’ own behavior. These are two different types of stimulus control that potentially can be affected in different ways. These procedures also allowed for examination of the effects of d-amphetamine on respondent and operant key pecks. If operant and respondent key pecks do occur in these schedules, the administration of d-amphetamine should yield differential results on each type of response. |
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