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| Parkinson's and Pesticides: Impact on Behavior |
| Sunday, May 28, 2006 |
| 1:30 PM–2:50 PM |
| Piedmont |
| Area: BPH; Domain: Basic Research |
| Chair: Adam Derenne (University of North Dakota) |
| Abstract: Although much is known about Parkinson's Disease and compounds used as pesticides, little is known about the behavioral effects of either. The speakers in this symposium have launched research programs to do exactly that - to study how learning, motivation, and memory is influenced by the development of Parkinson's Disease or exposure to pesticides. Interestingly, these programs may ultimately merge, as Parkinson's Disease is potentially an outcome of pesticide exposure. |
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| Parkinson's Disease I: Behavior of Weaver Mutant Mice under Progressive-ratio Schedules of Reinforcement. |
| DAVID P. AUSTIN (University of North Dakota), Adam Derenne (University of North Dakota), Jeffrey N. Weatherly (University of North Dakota) |
| Abstract: The research compares homozygous weaver mutant (wv/wv) mice expressing point mutation (G156S) in G-protein-coupled inward rectifying potassium channel to control mice. The mutation produces progressive nigrostriatal neurodegeneration and results in symptoms that mimic Parkinson’s disease in humans. The research describes changes in learning and motivation that occur in these mice in conjunction with known changes on the physiological level. Learning was defined in terms of the rate of acquisition of an operant response (nose poke), and motivation was defined in terms of performances under a progressive-ratio schedule of reinforcement. Preliminary findings suggest decrements on both measures for the mutant mice. |
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| Parkinson's Disease II: Longitudinal Changes in Learning and Memory in Weaver Mutant Mice. |
| ADAM DERENNE (University of North Dakota), Christine Wegner (University of North Dakota), Jeffrey N. Weatherly (University of North Dakota) |
| Abstract: The research examines a strain of homozygous Weaver mutant mice that spontaneously shows progressive nigrostriatal neurodegeneration, beginning at approximately 14 days of age. Memory was measured using a variant of a radial arm maze procedure in which 0.20% saccharine solution reinforcement was available from four dippers, positioned at cardinal points in the chamber. On each trial, the first visit to a dipper produced the reinforcer, but return visits did not. A new trial began once all four locations were visited. Sessions ended after subjects completed 10 trials or 10 minutes elapsed without a response. Performance was assessed in terms of trial duration, trials completed, and the number of return visits (errors) on each trial. The results showed that the Weaver mutant mice, compared to controls, completed fewer trials, committed more errors, and required more time to complete each trial. |
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| Pesticide I: The Effect of Exposure on the Acquisition of Operant and Respondent Behavior. |
| JASON W. DOUGLAS (University of North Dakota), Patrick A. Carr (University of North Dakota), Adam Derenne (University of North Dakota), Jeffrey N. Weatherly (University of North Dakota) |
| Abstract: Very little is known about how pesticide exposure influences behavior. The present study monitored the acquisition of operant and respondent behavior of rats that were exposed to one of five different types of agricultural pesticides commonly used in the upper midwest region of the United States. Some of the treatment animals received an acute intra-peritoneal dose of the pesticide whereas others received chronic injections every two weeks. Results demonstrated that pesticide exposure sometimes, but not always, influenced rates of acquisition. Furthermore, that influence varied across procedures (i.e., operant vs. respondent). Implications for future research and human application are discussed. |
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| Pesticide II: The Effect of Exposure on Timing and Reinforcer Efficacy. |
| JEFFREY N. WEATHERLY (University of North Dakota), Carol L. Wright (University of North Dakota), Patrick A. Carr (University of North Dakota), Adam Derenne (University of North Dakota) |
| Abstract: Rats were exposed to one of five different pesticides, either acutely or chronically. Afteracquisition training, they were responded in a multiple DRL 10-s FI 40-s schedule ofreinforcement for 5% liquid-sucrose reinforcers. They also responded in separate PR 5 sessionsfor food-pellet reinforcement. Results from the multiple schedule demonstrated that pesticideexposure altered rats’ responding in both components relative to controls, although pesticide-and/or administration-specific exceptions were observed. Significant differences in performancewere also observed on the PR schedule. The present results therefore suggest that pesticideexposure can alter timing behavior and change the efficacy of a reinforcer. Implications forhuman exposure are discussed. |
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