|
| Pharmacological and Non-Pharmacological Disruptors of Timing: Current Results and Theoretical Implications |
| Saturday, May 26, 2007 |
| 1:00 PM–2:20 PM |
| Ford C |
| Area: BPH; Domain: Basic Research |
| Chair: Kathryn A. Saulsgiver (University of Florida) |
| Discussant: Clive D. L. Wynne (University of Florida) |
| Abstract: The control of behavior by the passage of time can be demonstrated in a variety of procedures in many species. Numerous manipulations disrupt this timing behavior. Traditionally the impact of pharmacological agents has been conceptualized as interfering with dedicated timing mechanisms, while non-pharmacological interference on timing may be conceived of as a disturbance of stimulus control. In this symposium new results will be presented from two studies of the effects of d-amphetamine on a peak procedure and a matching-to-sample of duration (MTSD) task. A third study will report the effects of non-pharmacological disruptors such as pre-session feeding, intercomponent-interval feeding, visual distraction, and extinction on an MTSD tasks. These results will be integrated into a theoretical account of both pharmacological and non-pharmacological disruptors of timing. |
| |
| Effects of Acute and Chronic D-amphetamine on a Peak Interval Procedure in Pigeons: An Assessment of Multiple Variables. |
| KATHRYN A. SAULSGIVER (University of Florida), Erin A. McClure (University of Florida), Eric Beecher (University of Florida), Clive D. L. Wynne (University of Florida) |
| Abstract: The effects of amphetamine on temporally controlled behavior have been a debate in the timing literature. In some instances research has supported the explanation that an internal pacemaker controls temporal regulation (Meck, 1996, Maricq, Roberts, & Church 1981). Other research supports the theory that amphetamine causes a general disruption in behavior (Odum, Lieving, & Schaal 2003; McClure, Saulsgiver, & Wynne 2005; Saulsgiver, McClure, & Wynne, 2006), ruling out the pacemaker as a potential mechanism of action. Effects of acute and chronic dosing of d-amphetamine were examined using the peak interval procedure. Various methods have been used to assess responding under these schedules, both looking at the overall session average of response rates (Meck, 1996) and examining changes in the individual trials (Grace, Berg, & Kyonka, 2006). This examination assesses changes using both methods and considers the role of tolerance in these effects. The interaction across the various parameters will be evaluated. The reliability of each method in assessing changes will also be assessed. |
| |
| Effects of Acute and Chronic D-amphetamine Administration on Mediating Behavior in Pigeons Exposed to Two Variations of a Temporal Discrimination Procedure. |
| ERIN A. MCCLURE (University of Florida), Kathryn A. Saulsgiver (University of Florida), Eric Beecher (University of Florida), Clive D. L. Wynne (University of Florida) |
| Abstract: When rats are trained on spatial procedures to assess temporal discrimination, they must respond on one lever after a short stimulus and a different lever after a long stimulus. The introduction of amphetamine commonly causes a leftward shift in the psychophysical function for time. However, when pigeons are trained on non-spatial procedures, with colored keys as response alternatives, the effect of the drug is mainly on stimulus control and not on 'timing' per se. Previous studies have shown that when spatial alternatives are used, animals exhibit mediating behavior during the stimulus to be timed, creating a salient cue to aid in the choice response. The first purpose of the current study was to explore whether a difference between species could be attributable to procedural differences, by comparing the performance of pigeons on a spatial task to pigeons on a non-spatial task. Second, a systematic analysis was conducted to determine any effects of the drug on mediating behavior. During acute administration, the drug caused similar initial disruptions in responding regardless of procedure. During chronic administration, differences were found in the time course of tolerance. Analysis of mediating behavior could aid in the explanation of differential drug effects dependent upon procedure. |
| |
| Disruption of Temporal Discrimination and the Choose-Short Effect. |
| RYAN D. WARD (Utah State University), Amy Odum (Utah State University) |
| Abstract: The present experiment examined the effects of several disruptors on
temporal discrimination. Pigeons responded under a 0-delay symbolic
matching-to-sample procedure in which responses to one key color were reinforced following presentation of four shorter sample durations and responses to another key color were reinforced following presentation of four longer sample durations. Steady-state performance was disrupted by pre-session feeding, intercomponent-interval food, visual distraction, and extinction. All disruptors decreased temporal-discrimination accuracy. Analyses of the fitted cumulative normal functions indicated that decreases in accuracy were produced mainly by decreases in overall stimulus control, rather than specific effects on timing. In addition, all disruptors selectively decreased accuracy on long-sample trials-a choose-short effect. This effect is interpreted in terms of decreased attention to the samples under disruption. Current theories of the choose-short effect do not appear to easily account for these results. |
|
| |