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| Investigations of Schedule-Induced Behavior: Pausing, Escape, and Polydipsia |
| Sunday, May 28, 2023 |
| 5:00 PM–6:50 PM |
| Hyatt Regency, Centennial Ballroom B |
| Area: EAB/BPN; Domain: Basic Research |
| Chair: Carson Yahrmarkt (Northern Michigan University) |
| Discussant: Chris Hughes (University of North Carolina Wilmington) |
| Abstract: Under certain circumstances, the delivery of stimuli that serve as positive reinforcers can cause disruptions in operant behavior. The present symposium arranges four recent areas of research that further our understanding of these phenomena. The first presentation evaluates the control of pausing observed during transitions from rich schedules of reinforcement to lean schedules of reinforcement (i.e., rich-lean transitions) with rats by manipulating the kind of stimuli associated with the schedules. The second presentation evaluates situations in which pigeons escape auditory stimuli associated with rich-lean transitions. The third presentation investigates effects of pharmacological methods to control polydipsia in rats. The fourth presentation investigates pharmacological methods to ameliorate the disruptions caused by rich-lean transition with monkeys. The symposium will conclude with a discussion led by Dr. Christine Hughes. The goal of this collection of talks is to bring interested researchers up to speed with current research that investigates behavior that can be generated by the delivery of positive reinforcers and to highlight areas where future research could aid in our understanding of these phenomena. |
| Instruction Level: Intermediate |
| Keyword(s): Animal models, Polydipsia, Rich-lean transitions, Schedule-induced behavior |
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| Control of Pausing in Rich-Lean Transitions by Spatially Localized and Spatially Diffuse Stimuli |
| CARSON YAHRMARKT (Northern Michigan University), Forrest Toegel (Northern Michigan University), Cory Toegel (Northern Michigan University) |
| Abstract: Transitions from rich schedules of reinforcement to lean schedules (i.e., rich-lean transitions) can disrupt operant behavior. We arranged a two-component multiple fixed ratio-fixed ratio (FR-FR) schedule to evaluate effects of different types of schedule-correlated stimuli on pausing in rich-lean transitions using rat subjects. Components had equivalent FR requirements and were each signaled by unique schedule-correlated stimuli. In one component, rich, satisfying the FR requirement produced 3 food pellets. In the other component, lean, satisfying the FR requirement produced 1 food pellet. Each session consisted of 41 components arranged to produce 10 transitions of four types (rich-lean, rich-rich, lean-lean, lean-rich). Across conditions, we manipulated the type of stimuli that signaled the components. In one condition, Spatially Localized, the components were signaled by inserting one of two levers (e.g., right = rich, left = lean). In the other condition, Spatially Diffuse, the components operated on the same lever and were signaled by different tones (e.g., 500 Hz = rich, 1500 Hz = lean). Results and potential theoretical implications will be discussed. |
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Escape From Auditory Stimuli Associated With Rich-to-Lean Transitions |
| JEREMY SAUL LANGFORD (West Virginia University), Michael Perone (West Virginia University) |
| Abstract: Signaled transitions from rich-to-lean conditions of reinforcement have been shown to occasion several aberrant behaviors, including pausing, escape, and aggression. However, these measures are not strongly correlated. Although rich-lean transitions reliably produce extended pausing, escape either occurs at low rates or is undifferentiated across transition types. One potential barrier to studying escape from schedules of positive reinforcement is that unauthorized escape occurs (e.g., turning away from the response key). We have developed a version of the rich-to-lean procedure in which the components are signaled with tones (Hz between 500 and 3500) instead of colored response keys to mitigate the occurrence of unauthorized escape. Pigeons responded on a multiple fixed ratio fixed ratio schedule in which completion of each ratio resulted in either a large (rich) or small (lean) reinforcer presentation. Components alternated irregularly to arrange for four transition types: lean-lean, lean-rich, rich-lean, and rich-rich. Components were signaled with a unique tone that was correlated with the transition type that occurred at the start of the component. We found extended rich-lean pausing under the auditory version of the rich-lean procedure for some pigeons. Current manipulations aim to compare the probability of escape across the auditory and visual versions of the procedure. |
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Effects of Dextromethorphan on Schedule-Induced Polydipsia in Rats |
| MADELINE T VAN FOSSEN (Northern Michigan University), Adam J. Prus (Northern Michigan University) |
| Abstract: Dextromethorphan (DM) is a sigma1 receptor agonist and over-the-counter cough suppressant. DM is also FDA-approved for pseudobulbar affect, and is approved, in combination with bupropion, for the treatment of major depressive disorder. Antidepressant drugs with sigma1 receptor agonist activity attenuate symptoms of obsessive-compulsive disorder (OCD). The present study aimed to evaluate the effects of DM in rats using the schedule-induced polydipsia procedure, a model of compulsive behavior. In this paradigm, food-, but not water-, restricted animals drink excessive amounts of water when food is delivered on a fixed schedule. This study examined male Wistar rats (food restricted to 85% of free-feed weights) during 60 min sessions with fixed-time 60 second schedules and free access to a lickometer-equipped water-bottles. Following 20 consecutive daily training sessions, rats were divided into high or low drinker groups. Dextromethorphan (15.0 to 60.0 mg/kg) dose-dependently reduced water consumption and frequency of licks in both the low and high drinker groups. DM reduced food-receptacle head entries in only the low drinker group. Based on these findings, DM may be effective for treating compulsive behavioral disorders. |
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Using Rich-Lean Transition Procedures as an Assay for Putative Anti-Anxiety Medications |
| Forrest Toegel (Northern Michigan University), Cory Toegel (Northern Michigan University), James K. Rowlett (University of Mississippi Medical Center), Austin Zamarripa (Johns Hopkins University School of Medicine
), SALLY L. HUSKINSON (University of Mississippi Medical Center) |
| Abstract: Potential anti-anxiety medications are commonly assessed by measuring their “anti-conflict” effects. While these procedures have good predictive validity, there are practical limitations that may be alleviated using a different procedure. Transitions from favorable to unfavorable schedules of positive reinforcement (rich-lean transitions) disrupt operant behavior, are putatively aversive, and these disruptions can be reduced following benzodiazepine administration. We evaluated the suitability of a rich-lean transition procedure as an assay for potential anti-anxiety medications. Adult rhesus monkeys’ lever presses were reinforced using a two-component multiple schedule with equivalent fixed-ratio (FR) requirements. Components were differentially signaled by colored cue lights. Completing a lean component produced one food pellet, and completing a rich component produced four food pellets. Sessions consisted of 41 components arranged irregularly to produce 10 iterations of four transition types: rich-lean, rich-rich, lean-lean, and lean-rich. Consistent with previous findings, extended pausing was observed in rich-lean transitions. Acute administration of benzodiazepines (midazolam and alprazolam) and a benzodiazepine-type compound (TPA023B) selectively and dose-dependently reduced pausing in rich-lean transitions, morphine selectively increased rich-lean pausing, and (+)amphetamine had unsystematic effects. Thus far, repeated (5-day) benzodiazepine administration also reduced pausing in rich-lean transitions. The suitability of rich-lean procedures as assays for putative anti-anxiety medications appears promising. |
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