10 research outputs found
Effects Of Daily Morphine Administration And Deprivation On Choice And Demand For Remifentanil And Cocaine In Rhesus Monkeys
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96717/1/jeab.2011.95-75.pd
Resistencia al cambio en programas de evitaci贸n y tiempo-fuera de evitaci贸n
Galizio (1999) report贸 que una respuesta que produc铆a un tiempo fuera dela evitaci贸n era m谩s resistente a la extinci贸n que la respuesta de evitaci贸n misma. El presente estudio busca extender ese hallazgo. Seis veces durantecada sesi贸n, un programa se帽alado de raz贸n fija 10 fue impuesto sobre unprograma de eliminaci贸n de choque de ciclo variable choque-choque de 60 s.Al completar la raz贸n, las ratas produc铆an un tiempo fuera se帽alado de 5 u 8minutos. Se compararon las tasas de respuesta mantenidas por la evitaci贸ny el tiempo fuera analizando la respuesta durante cada presentaci贸n (tiempofuera) de la RF y en el per铆odo previo de 5 min (evitaci贸n). La resistencia alcambio fue determinada mediante (a) un incremento el par谩metro de ciclovariable de 60 a 120 s (Experimento 1), y (b) una extinci贸n por omisi贸n dechoques (Experimento 2). En ambos casos, la respuesta de tiempo fuera fuem谩s resistente al cambio que la respuesta de evitaci贸n
Assessing Unit鈥怭rice Related Remifentanil Choice In Rhesus Monkeys
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96725/1/jeab.2006.108.05.pd
Acquisition Of Cocaine Self-Administration With Unsignaled Delayed Reinforcement In Rhesus Monkeys
Six experimentally naive rhesus monkeys produced 0.01鈥卪g/kg/infusion cocaine by lever pressing under a tandem fixed-ratio 1 differential-reinforcement-of-other-behavior schedule. One lever press initiated an unsignaled 15- or 30-s delay culminating in cocaine delivery. Each press made during the delay reset the delay interval. With two exceptions, responding was acquired and maintained at higher rates than responding on a second (inoperative) lever. For the exceptions, a cancellation contingency was arranged in which each formerly inoperative-lever response reset the tandem schedule. This manipulation reduced presses on the inoperative lever. Subsequently, the consequences of responding on the two levers were reversed, and the monkeys again responded at higher rates on the operative lever. As a comparison, 3 additional experimentally naive monkeys received response-independent cocaine deliveries. Although lever pressing was observed, it extinguished and was subsequently reestablished under the tandem schedule. The results suggest that although response-reinforcer contiguity is not required for cocaine to acquire reinforcing functions, a response-reinforcer relation appears necessary
ASSESSING THE ROLE OF EFFORT REDUCTION IN THE REINFORCING EFFICACY OF TIMEOUT FROM AVOIDANCE
Response Acquisition and Fixed-Ratio Escalation Based on Interresponse Times in Rats
The effectiveness of a fixed-ratio (FR) escalation procedure, developed by Pinkston and Branch (2004) and based on interresponse times (IRTs), was assessed during lever-press acquisition. Forty-nine experimentally na茂ve adult male Long Evans rats were deprived of food for 24 hr prior to an extended acquisition session. Before the start of the session, three food pellets were placed in the magazine. Otherwise, no magazine training, shaping, nor autoshaping procedure was employed. The first 20 presses each resulted in the delivery of a 45-mg food pellet. Then, the FR increased (2, 4, 8, 11, 16, 20, 25, 30) when each IRT in the ratio was less than 2 s during three consecutive ratios. Sessions lasted 13 hr or until 500 pellets were earned. On average, rats reached a terminal ratio of 11 (mean) or 16 (median) during the first session. Seven rats reached the maximum value of FR 30 and only one rat did not acquire the response. In most rats, a break-and-run pattern of responding characteristic of FR schedules began to develop in this acquisition session. Subsequently, the ratio-escalation procedure continued during daily 2-hr sessions. In these sessions, the starting ratio requirement was set at the terminal ratio reached in the previous session. Using this procedure, over half (26) of the rats reached the FR 30 requirement by the fourth session. These data demonstrate that a ratio-escalation procedure based on IRTs provides a time-efficient way of establishing ratio responding
Behavioral Perspectives on the Neuroscience of Drug Addiction
Neuroscientific approaches to drug addiction traditionally have been based on the premise that addiction is a process that results from brain changes that in turn result from chronic administration of drugs of abuse. An alternative approach views drug addiction as a behavioral disorder in which drugs function as preeminent reinforcers. Although there is a fundamental discrepancy between these two approaches, the emerging neuroscience of reinforcement and choice behavior eventually may shed light on the brain mechanisms involved in excessive drug use. Behavioral scientists could assist in this understanding by devoting more attention to the assessment of differences in the reinforcing strength of drugs and by attempting to develop and validate behavioral models of addiction