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| Recent Developments in Animal Models of Drug and Toxicant Exposure |
| Monday, May 31, 2004 |
| 2:30 PM–3:20 PM |
| Beacon E |
| Area: BPH |
| Chair: M. Christopher Newland (Auburn University) |
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| Seizures Cause Impairment in Auditory Discrimination |
| Domain: Applied Research |
| JOHN C. NEILL (Long Island University), Gregory Holmes (Dartmouth Medical School) |
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| Abstract: A variety of animal models of epilepsy (kainic acid, pilocarpine, flurothyl, kindling) were used to investigate the effects of seizures on auditory discrimination. Go right-go left and go - no go paradigms were used in combination with location or quality (frequency) cues. Naturalistic auditory stimuli produced rapid acquisition in rat (10/10 rats) and epileptics (5/5 humans). One episode of status epilepticus (kainic acid or pilocarpine) produced long-term impairment in auditory location discrimination (go right - go left, 12/12 rats). Pilocarpine-induced status epilepticus induced early in development caused less long-term impairment in auditory location discrimination (4/4) than one induced late in development (4/4). Status epilepticus early in development caused impairment in acquiring the auditory location discrimination (go right - go left, 4/4 rats) but not epilepsy. Further training with sound quality (frequency) cues preceded perfect acquisition of the auditory location discrimination (4/4 rats). One probe flurothyl seizure totally disrupted performance 24 hours later (3/4 rats). Serial brief seizures induced with flurothyl early in development caused long-term impairment in auditory location but not frequency discrimination (go-no go), and did not cause epilepsy (6/6 rats). Auditory discrimination paradigms offer sensitivity to impairments in discrimination in humans and rats following seizures. |
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| Behavior in Transition under Concurrent Schedules of Reinforcement Following Drug and Toxicant Exposure |
| Domain: Applied Research |
| PHYLLIS REILE (Auburn University), Elliott M. Paletz (Ball State University), Wendy Donlin Washington (Auburn University), M. Christopher Newland (Auburn University) |
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| Abstract: The necessity for selecting molecular measures to record moment-by-moment dynamics of behavior may provide an advantage for examining functional changes in behavior resulting from drug or toxicant exposure. This paper will address the use of a mixed concurrent RI (random-interval)-RI schedules procedure and whether it is designed to detect perturbation of functionally diverse response units. Behavior change was examined during 2.5 hour sessions with rats exposed to acute doses of haloperidol and d-amphetamine (before sessions) or gestational exposure to methylmercury (prior to the experiment). Among other quantifications, a logistic equation will be used for describing within-session changes in responding. Different measures, such as the slope of the equation (i.e., rate of change in local response-ratios) or the peak response-ratio following the transition, provide additional and possibly functionally independent variables to evaluate perturbation of behavior. For example, changes in local response-ratios may be driven more by changes in response-rate on the "lean" lever without a corresponding increase in response-rate on the "rich" lever. Thus, although demanding in the short run, this procedure may be advantageous in the long run by replacing the need for several studies to examine the effects of the same compounds on possibly unrelated behavioral functions. Supported by ES10865 from NIH. |
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