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  • 1
    Electronic Resource
    Electronic Resource
    Human neuropsychology: Some differences between korsakoff and normal operant performance (1980)
    Springer
    Psychological research 41 (1980), S. 235-247 
    Details
    ISSN: 1430-2772
    Source: Springer Online Journal Archives 1860-2000
    Topics: Psychology
    Notes: Summary Operant reinforcement schedules were used to investigate the effects of changes in reinforcement rates on the behavior of alcoholic Korsakoff (amnesic) patients and normal control subjects. In one test, both groups were exposed to pairs of variable-interval (VI) reinforcement schedules which operated concurrently. The distribution of reinforcements controlled the distribution of responses of normal subjects to a significantly greater extent than those of the Korsakoff patients. In a second test, two VI reinforcement schedules were arranged to run one at a time in succession. Reinforcement-rate differences with the successive (multiple) schedules did not produce corresponding response-rate differences for either group of subjects. The findings stress the complexity of the alcoholic Korsakoff syndrome, and emphasize the need to consider possible motivational abnormalities as determinants of alcohol-induced amnesia. In addition, results underscore both the value and the limitations of using operant procedures in human learning research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308659
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    A parametric description of amphetamine's effect on response rate: changes in reinforcement efficacy and response topography (1985)
    Springer
    Psychopharmacology 85 (1985), S. 154-161 
    Details
    ISSN: 1432-2072
    Keywords: d-Amphetamine ; Response rate ; Reinforcement efficacy ; Response topography ; Matching law ; Rate-dependency ; Variable-interval schedule ; Lever press ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A mathematical model was used to describe the effects of amphetamine on the rate of a reinforced response in the rat. The model provides measures of reinforcement efficacy and response topography for behavior maintained by variable-interval reinforcement schedules. In this study the measured behavior was a lever press, the reinforcer was water, and the variable-interval schedules provided five different rates of reinforcement, ranging from about 20 to 660/h. In each session the rats were exposed to each of the five schedules, and as reinforcement rate increased, the rate of lever pressing increased in a negatively accelerated manner that was closely approximated by the equation for a rectangular hyperbola. Amphetamine changed responser rate and the parameters of the best-fitting hyperbolas. The 0.25–1.0-mg/kg doses increased response rate, and the parameter changes supported the interpretation that the increases were due primarily to an increase in reinforcement efficacy. The 2.0- and 3.0-mg/kg doses decreased response rates maintained by low reinforcement rates and increased response rates maintained by high reinforcement rates, and the parameter changes supported the interpretation that at higher doses amphetamine produced counteracting changes in reinforcement efficacy and response topography: reinforcement efficacy decreased, whereas response topography changed so as to increase response rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428406
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Preference for saccharin-sweetened alcohol relative to isocaloric sucrose (1997)
    Springer
    Psychopharmacology 129 (1997), S. 72-78 
    Details
    ISSN: 1432-2072
    Keywords: Key words Alcohol self-administration ; Choice ; Animal model ; Behavioral economics ; Substitutability ; Ethanol ; Sucrose ; Quinine ; Variable-interval schedule ; Lever press ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This experiment tested the reinforcing efficacy of a saccharin-sweetened alcohol solution relative to an isocaloric sucrose drink in rats. One dipper served 10% alcohol plus 0.25% saccharin, and a second, concurrently available, dipper served 14.2% sucrose. During the course of the experiment, access to the two drinks was challenged by increasing the schedule requirement (variable-interval) that determined when a lever press would operate the dipper. There were two main findings. First, the rats continued to consume significant amounts of alcohol despite access to the isocaloric sucrose solution. Second, schedule-requirement increases that decreased sucrose-reinforced responding failed to decrease saccharin-sweetened alcohol reinforced responding. These results extend and replicate earlier findings from studies in which alcohol was mixed with sucrose, and the alcohol mixtures held a caloric advantage over the competing sucrose solutions. The experiment also included controls for differences in baseline response rates and for the influence of saccharin on preference. In the baseline response-rate control conditions, the two reinforcers were 10% sucrose and a mixture of 10% sucrose-plus-quinine. The results showed that the persistence of sweetened-alcohol reinforced responding could not be explained by differences in baseline response rates or the reinforcing properties of saccharin. Rather, the findings were consistent with the idea that the rats were defending baseline levels of alcohol-plus-saccharin consumption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050164
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Chlorpromazine and pimozide alter reinforcement efficacy and motor performance (1986)
    Springer
    Psychopharmacology 88 (1986), S. 346-353 
    Details
    ISSN: 1432-2072
    Keywords: Chlorpromazine ; Pimozide ; Response rate ; Reinforcement efficacy ; Motor performance ; Matching law ; Variable-interval schedule ; Lever press ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study evaluated the effects of chlorpromazine and pimozide on reinforced responding. In each session, rats were exposed to a series of five variable-interval reinforcement schedules. The response requirement was a lever press, the reward was a small portion of water, and the reinforcement rate varied from about 20 to 660 reinforcers per hour. Response rate was a negatively accelerated function of reinforcement rate, and the relationship between the two variables was described by the equation for a rectangular hyperbola (the matching law). One parameter of the hyperbola is equivalent to the asymptotic response rate and the other parameter is equivalent to the rate of reinforcement that maintains a one-half asymptotic response rate. Chlorpromazine (0.75–3.0 mg/kg) and pimozide (0.1–0.4 mg/kg) dose-dependently decreased response rates. At low doses, the response rate decreases were, for the most part, restricted to the low reinforcement rate schedules. In contrast, the highest dose tested decreased response rates at both low and high reinforcement rates. The patterns of response rate decreases resulted in dose-dependent changes in the parameters of the matching law equation. The shifts in the matching law parameters were discussed in terms of the motoric and motivational interpretations of neuroleptic-induced response rate changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180837
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of methylphenidate on response rate and measures of motor performance and reinforcement efficacy (1992)
    Springer
    Psychopharmacology 109 (1992), S. 145-152 
    Details
    ISSN: 1432-2072
    Keywords: Methylphenidate ; Response rate ; Reinforcement efficacy ; Motor performance ; Matching law ; Response strength equation ; Rate dependency principle ; Clinical effects ; Variable-interval schedule ; Lever press ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This experiment evaluated the effects of methylphenidate on reinforced responding in rats. In each session the subjects (rats) earned reinforcement on seven different variable-interval reinforcement schedules. The average intervals varied from 108 to 3 s and provided reinforcement rates ranging from about 30 to 1100/h. Response rate was a negatively accelerated function of reinforcement rate. Low doses of methylphenidate (1.0 and 2.0 mg/kg) increased responding maintained by the four leanest schedules, but had little effect on responding maintained by the three densest schedules. In contrast, an 8.0 mg/kg dose increased responding maintained by the three densest schedules and slightly decreased responding maintained by leaner schedules. A quantitative model of reinforced responding, referred to as the matching law or response strength equation, was fitted to the data. This equation has two parameters. On the basis of previous experiments, one was used to measure changes in reinforcement efficacy and the other was used to measure changes in motor performance. The 1.0 and 2.0 mg/kg doses changed the reinforcement parameter in the same way as did increases in deprivation and reward magnitude. The 8.0 mg/kg dose changed the motor parameter in the same was as did decreases in lever weight. It was concluded that methylphenidate increases reinforcement efficacy, and that the highest dose changed the topography of responding. The results are discussed in terms of the response strength equation, the rate dependency principle, and the question of how to interpret changes in reinforcement efficacy and motor performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02245492
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  • 6
    Electronic Resource
    Electronic Resource
    Ethanol regulated preference in rats (1993)
    Springer
    Psychopharmacology 112 (1993), S. 259-269 
    Details
    ISSN: 1432-2072
    Keywords: Ethanol ; Preference ; Substitutability ; Body weight ; Calories ; Sucrose ; Animal model of ethanol preference ; Alcohol ; Choice ; Variable-interval schedule ; Concurrent schedule ; Lever press ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A series of experiments evaluated the determinants of preference for mixtures of ethanol plus sucrose relative to sucrose in rats. One dipper served 10% ethanol mixed with 10% sucrose, and the second dipper served 10% sucrose. Lever presses operated each dipper according to a variable-interval 5-s schedule. In three experiments the subjects were given pre-session meals of sucrose (2.5–20 ml) or sucrose (20 ml) plus chow (5 or 10 g). Pre-session meals decreased responding maintained by sucrose but not responding maintained by ethanol mixture. In two experiments body weight was varied from 85% to 125% of the initial free-feeding values. Increases in body weight, like pre-session meals, decreased responding reinforced by sucrose, but typically did not decrease responding reinforced by ethanol mixture. Throughout most of the study, ethanol consumption remained at about 1.25 ml per half hour session (3–4 g/kg per 30 min). For example, pre-session access to ethanol mixture decreased within-session ethanol consumption, but total consumption, counting both sources, remained about 1.25 ml/session. The within-session patterns of responding also differed. Responding reinforced by ethanol mix decreased as a function of ethanol consumption, whereas responding reinforced by sucrose was relatively constant throughout the session. The simplest explanation of the results is that ethanol's pharmacological consequences regulated preference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02244920
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