Why Tolerance to Cocaine's Effects on Fixed-Interval Performance is Different from That on Fixed-Ratio Performance
|Tuesday, August 14, 2007|
|8:00 AM–8:50 AM |
|Area: BPH; Domain: Experimental Analysis|
|CE Instructor: Marc N. Branch, Ph.D.|
|Chair: Kennon A. Lattal (West Virginia University)|
|MARC N. BRANCH (University of Florida)|
|Dr. Marc Branch has conducted impressive and definitive research in a number of areas related to basic operant conditioning, including memory, observing behavior, and reinforcement schedules.
He is best known for directing one of the country's leading programs in behavioral pharmacology. He and his students have conducted a long line of research on agents such as pentobarbital, d-amphetamine, and cocaine, and on environmental factors that influence drug tolerance. This work has been funded continuously for 30 years by National Institute of Mental Health (NIMH) and National Institute on Drug Abuse (NIDA) and has been published in the flagship journals in both behavior analysis and pharmacology. In recognition of this consistent track record of excellence, he has been the recipient of a coveted research career award from NIMH.
Dr. Branch has held a number of leadership positions in our field, including president of ABA International and Society for the Experimental Analysis of Behavior, editor of Journal of the Experimental Analysis of Behavior and The Behavior Analyst, and either member or chair of study sections for the past 25 years. He is a Fellow in both the American Psychological Association and the American Psychological Society.|
Previous research has revealed that tolerance to cocaine's effects on behavior under fixed-ratio (FR) schedules depends on the FR parameter. In contrast, tolerance to the drug's effects on behavior under fixed-interval schedules has been unrelated to FI parameter. Although FI and FR schedules with equivalent inter-reinforcement times result in roughly equivalent average post-reinforcement pause times, the distributions of pauses differ. Specifically, the conditional probability of ending the pause grows with time on FI schedules, but remains constant on FR schedules, a difference that may be related to the fact that longer pauses on FI schedules are associated with shorter delays to reinforcement, whereas that relation does not exist for FR schedules. To test whether that difference plays a role in the FI-FR difference in drug effects, pigeons were trained under a response-initiated FI schedule, wherein the FI starts timing when the pause ends. Under those conditions, tolerance was related to FI parameter.