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| Advanced Issues in Nonhuman Behavioral Pharmacology |
| Sunday, May 30, 2010 |
| 1:30 PM–2:50 PM |
| Travis C/D (Grand Hyatt) |
| Area: BPH; Domain: Experimental Analysis |
| Chair: Meredith S. Berry (Utah State University) |
| Abstract: This symposium brings together several lines of research from laboratories investigating nonhuman drug/behavior relations. The first presenter will discuss the effects of d-amphetamine on behavior punished by timeout from positive reinforcement in pigeons under multiple random-interval and random-ratio schedules of reinforcement. The second presenter will discuss the effects of nicotine on delayed-matching-to-sample performance in pigeons to assess any of the purported enhancements the drug is said to have on memory. The third presenter will discuss the effects of drugs from several pharmacological classes on disruption of behavior maintained under a multiple schedule with varying amounts of food in both pigeons and rats. Finally, the fourth presented will discuss the role of changes in reinforcer effectiveness in modulating the effects of cocaine on operant responding with pigeons under acute and chronic administration. |
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| Effects of d-Amphetamine on Behavior Punished by Timeout From Positive Reinforcement |
| CHRISTINE E. HUGHES (University of North Carolina, Wilmington), Emily Jones (University of North Carolina, Wilmington) |
| Abstract: The purpose of this experiment was to examine the effects of d-amphetamine on behavior punished by timeout from positive reinforcement. Three pigeons responded under a multiple random-interval (RI) 6-min RI 1-min schedule of food presentation. There were six, 5-min components. A random ratio (RR) schedule of time-out then was added to the RI 1-min component. Initially, the timeouts were 20 s in duration and followed responses immediately with a probability of .33 (RR3) for 2 pigeons and with a probability of .50 (RR2) for 1 pigeon. These timeouts generally decreased response rates by 50%. d-Amphetamine (0.3, 1.0, 1.8, 3.0, 5.6 mg/kg) then was administered. Across pigeons, d-amphetamine generally decreased response rates in the unpunished component. For 2 subjects, it also decreased response rate in the punished component; for 1 pigeon it increased response rates in the unpunished component. These different results may be based on the baseline rates of punished responding; thus, different timeout durations and/or probabilities were arranged and d-amphetamine’s effects were re-examined. |
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| Effects of Nicotine on Delayed-Matching-to-Sample Performance |
| BRIAN D. KANGAS (University of Florida), Marc N. Branch (University of Florida) |
| Abstract: Emerging evidence suggests that nicotine administration may enhance short-term remembering. Much of this evidence comes from nonhuman primate studies using a procedure called delayed matching-to-sample, wherein the animal is trained to select a comparison stimulus that matches some physical property of a previously presented sample stimulus. Delays between sample stimulus offset and comparison stimuli onset are manipulated, accuracy is measured, and a forgetting function (i.e., the relation between accuracy and delay) is derived. The present research examined nicotine’s effects on delayed matching-to-sample performance in pigeons. The study examined nicotine’s effects under acute (i.e., drug administrations separated by several days) and chronic (i.e., daily injections) administration to determine if any effects on short-term remembering would persist over multiple sessions, or if tolerance to nicotine’s effects would be observed. The study failed to provide much evidence of enhancement of remembering following nicotine administration despite reliable and systematic dose-related changes in other measures of the remembering task. A modest dose-related effect on accuracy of a very circumscribed subset of trial types, however, was found, but both the magnitude and importance of the effect appears to be directly related to tactics of data analysis leaving the effect dubious at best. |
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| Reinforcement Magnitude Modulation of Behavioral Drug Effects |
| BRETT C. GINSBURG (University of Texas HSC-H), Jonathan W. Pinkston (UT Health Science Center at San Antonio), R.J. Lamb (University of Texas HSC-H) |
| Abstract: Behaviors maintained by greater amounts of reinforcement are more resistant to disruption by prefeeding or extinction. However, the extent to which behavioral disruption by drugs also depends on reinforcement magnitude remains unclear. We assessed effects of drugs from several pharmacological classes on disruption of behavior maintained under a multiple schedule with varying amounts of food in both pigeons and rats. In both species, responding was maintained under a multiple fixed-interval (300-s) schedule and resulted in presentation of grain for 2-, 4-, or 8-sec for pigeons or delivery of 2 or 10 food pellets (45mg) for rats. No differences in drug effects on overall response rate were evident in either species for any drug. Antidepressants (fluvoxamine and desipramine) exerted rate-dependent effects that were blunted by increasing amounts of reinforcement in both species. Drugs from other classes (amphetamine, cocaine, pentobarbital, and chlordiazepoxide) exerted rate-dependent effects in both species, but modulation by reinforcement magnitude was inconsistent across doses and species. Modulation of rate-dependent effects by reinforcement magnitude appears to generalize across antidepressants, but not stimulants or sedatives. In conclusion, disruption of behavior by drug administration is not influenced by reinforcement magnitude as robustly as other events such as prefeeding and extinction. |
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| A Within-Subject Comparison of Effects of Acute and Chronic Cocaine on Key Pecking and Eating in Pigeons |
| DAVID R. MAGUIRE (University of Florida), Marc N. Branch (University of Florida) |
| Abstract: The purpose of the present research was to examine the role of changes in reinforcer effectiveness in modulating the effects of cocaine on operant responding. In this study we compared effects of acute and chronic cocaine administration on an operant response (key pecking) with effects on reinforcer consumption (commerce with the grain hopper). In addition, effects of cocaine were compared to effects of prefeeding. Pigeons responded under a multiple fixed-interval, fixed-time schedule of grain presentation. During the acute phase, a range of doses of cocaine (0.3 mg/kg to 13.0 mg/kg) was tested. During the chronic (daily administration) phase, a single dose of cocaine was given prior to each session, and a range of doses was tested as during the acute phase. Prefeeding occurred prior to select sessions during both the chronic-drug regimen and a subsequent withdrawal phase. Quantitative analyses were then used to derive estimates of the sensitivity of each response class (i.e., reinforcer production and reinforcer handling) to both the drug and prefeeding regimens. |
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