|Marijuana, Munchies, and Moments: Current Research on Discrimination of Interoceptive and Temporal Stimuli
|Monday, May 26, 2014
|11:00 AM–11:50 AM
|W175c (McCormick Place Convention Center)
|Area: EAB/TPC; Domain: Basic Research
|Chair: Travis Ray Smith (Southern Illinois University Carbondale)
Behavior analytic interpretations of subjective experience rest upon discrimination of complex relations between environmental stimuli and behavior. Often those discriminations involve interoceptive, private stimuli or spatiotemporally diffuse relations between public stimuli and behavior. This session will be composed of three papers assessing basic research questions related to discriminative control by these complex stimuli. Kangas describes similarity and differences of delta-9-tetrahydrocannabinol (THC) and anandamide in subjective drug effects and behavioral performances on a remembering task. Jewett explains how a food deprivation discrimination task is used to determine what compounds or nutrients produce subjective states correlated with food deprivation (i.e., hunger) or satiety. Brooks demonstrates how an apparent failure of exteroceptive stimulus control can be understood when subjects responding are shown to be an orderly function of the longest schedule requirement in a variable-interval schedule. The results of these basic behavioral studies can provide the empirical grounding for interpretations of consciousness and self-awareness in everyday situations and perhaps inform our understanding of clinically relevant behavior problems.
|Keyword(s): cannabinoid discrimination, hunger discrimination, subjective experience, temporal discrimination
Acute Food Deprivation Discrimination and the Search for New Treatments of Eating-related Conditions
|DAVID C. JEWETT (University of Wisconsin-Eau Claire)
The present talk will describe a novel application of discrimination techniques to further our understanding of the processes associated with the regulation of food intake. We trained rats to discriminative between 22 and 2 hours acute food deprivation in a two-choice operant task. After acquisition of the discrimination, generalization tests were conducted with a variety of orexigenic (feeding-inducing) and anorectic (feeding-suppressing) compounds to determine to what extent compounds that affect food consumption also alter or mimic the discriminative stimulus effects of acute food deprivation. Other tests involved medications with current clinical uses in humans. Results will be discussed both in terms of pharmacological and nutritional mechanisms of action. Results of generalization tests assessing the ability of solid and liquid solutions to alter the discriminative stimulus effects of acute food deprivation will also be discussed. Our findings indicate discrimination tasks can be used to further the understanding of normal biological processes, and these results may also complement the search for better therapeutics.
|Drug Discrimination as a Benchmark for Emerging Assays in Preclinical Pharmacology
|BRIAN D. KANGAS (Harvard Medical School)
|Abstract: Drug discrimination procedures have provided a wealth of pharmacological information about behaviorally active drugs including receptor selectivity, potency, efficacy, and indications of abuse liability. The present talk will describe how drug discrimination can also serve as a useful interoceptive standard upon which to juxtapose more complex behavioral endpoints. We studied a variety of cannabinergic CB1 agonists, including delta-9-tetrahydrocannabinol (THC), the primary psychoactive ingredient of marijuana. This class of drugs may produce medicinal effects but also may have deleterious effects on cognitive endpoints that cloud their use and further development. Squirrel monkeys engaged in touchscreen-based learning and memory tasks. The effects of several cannabinergic drugs revealed adverse effects on learning and memory at doses comparable to those required to be reliably reported by the subject as THC-like. However, the endocannabinoid anandamide produced no adverse effects, even following doses much larger than those needed to fully generalize to THC. These results indicate that drugs may differ in the relative potency with which they produce comparable interoceptive effects, presumably a measure of their useful receptor-mediated actions, and undesirable effects using cognitive endpoints. The dose ratio of discriminative-stimulus to such adverse effects may provide preclinical evidence of relative safety among therapeutic alternatives.
Temporal Discrimination of Inter-reinforcer Intervals in a Modified Stimulus Compounding Procedure
|MICHAEL BROOKS (Central Michigan Univeristy)
Stimulus compounding is a procedure in which two or more discriminative stimuli, trained separately, are presented simultaneously in probe sessions and typically results in summated response rates of the compound components. The purpose of this study was to produce the compounding effect of additive summation using stimuli that, during training, alternated daily rather than within the session as is more traditionally done with multiple schedules. Six Sprague-Dawley rats were trained to lever press under a variable-interval 60-s schedule in the presence of either a light or tone stimulus, with the absence of the light and tone signaling extinction. Sessions featuring light or tone alternated daily and were separated by extinction sessions. After extensive training on this procedure, compound probes revealed no evidence of additive summation when the light and tone were presented together. Subjects responded steadily during extinction sessions until a length of time equal to the longest interval of the variable interval schedule had elapsed, at which point responding ceased. Although responding was intended to come under control of exteroceptive tone and light stimuli, it appears that the longest constituent schedule within the array of VI values gained control over responding via acquisition of a more abstract temporal discrimination.