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.
Similar content being viewed by others
References
Bradshaw CM (1977) Suppression of response rates in variable-interval schedules by a concurrent schedule of reinforcement. J Psychol 68:437–480
Bradshaw CM, Ruddle HV, Szabadi E (1981) Relationship betwen response rate and reinforcement frequency in variable-interval schedules: II Effect of the volume of sucrose reinforcement. J Exp Anal Behav 35:263–269
Bradshaw CM, Szabadi E, Ruddle HV (1983) Herrnstein's equation: effect of response force requirement on performance in variable-interval schedules. Behav Anal Lett 3:93–100
de Villiers PA, Herrnstein RJ (1976) Toward a law of response strength. Psychol Bull 83:1131–1153
Dews PB, Wenger GR (1977) Rate-dependency of the behavioral effects of amphetamine. In: Thompson T, Dews PB (eds) Advances in behavioral pharmacology, vol 1. Academic Press, New York, pp 167–227
Fleshler M, Hoffman HS (1962) A progression for generating variable-interval schedules. J Exp Anal Behav 5:529–530
Franz DN (1980) Central nervous system stimulants. In: Gilman AG, Goodman LS, Gilman A (eds) Goodman and Gilman's The pharmacological basis of therapeutics, 6th edn. Macmillan, New York, pp 585–591
Hamilton AI, Stellar JR, Hart EB (1985) Reward, performance, and the response strength method in self-stimulating rats: validation and neuroleptics. Physiol Behav 35:897–904
Herrnstein RJ (1961) Relative and absolute strength of response as a function of frequency of reinforcement. J Exp Behav 4:267–272
Herrnstein RJ (1970) On the law of effect. J Exp Anal Behav 13:242–266
Herrnstein RJ (1974) Formal properties of the matching law. J Exp Anal Behav 21:159–164
Heyman GM (1983) A parametric evaluation of the hedonic and motoric effects of drugs: pimozide and amphetamine. J Exp Anal Behav 40:113–122
Heyman GM (1988) How drugs affect cells and reinforcement affects behavior: formal analogies. In: Commons ML, Church RM, Stellar JR, Wagner AR (eds) Quantitative analyses of behavior, vol VII. Erlbaum, Hillsdale, pp 157–182
Heyman GM Monaghan MM (1987) Effects of changes in response requirement and deprivation on the parameters of the matching law equation: new data and review. J Exp Psychol [Anim Behav Proc] 13:384–394
Heyman GM, Monaghan MM (1990) Contributions of the matching law to the analysis of the behavioral effects of drugs. In: Barrett JE, Thompson T, Dews PB (eds) Advances in behavioral pharmacology, vol 7. Erlbaum, Hillsdale, pp 39–77
Heyman GM, Seiden LS (1985) A parametric description of amphetamine's effect on response rate: Changes in reinforcement efficacy and response topography. Psychopharmacology 85:154–161
Heyman GM, Kinzie DL, Seiden LS (1986) Chlorpromazine and pimozide alter reinforcement efficacy and motor performance. Psychopharmacology 88:346–353
Higgins ST, Spitzer ML (1988) Time allocation in a concurrent schedule of social interaction and monetary reinforcement: Effects ofd-amphetamine. Pharmacol Biochem Behav 31:227–231
Klein RG (1987) Pharmacotherapy of childhood hyperactivity: an update. In: Meltzer HY (ed) Psychopharmacology: the third generation of progress. Raven Press, New York, pp 1215–1224
Ksir C (1981) Rate convergent effects of drugs. In: Thompson T, Dews PB, McKim WA (eds) Advances in behavioral pharmacology, vol 3. Academic Press, New York, pp 39–59
McSweeney FK (1978) Prediction of concurrent key peck and treadle-press responding from simple schedule performance. Anim Learn Behav 6:444–450
Petry NM, Heyman GM (1992) Differential effects of food and water deprivation on the parameters of the matching law equation. (in press).
Pickens R (1977) Behavioral Pharmacology: a brief history. In: Thompson T, Dews PB (eds) Advances in behavioral pharmacology, vol 1. Academic Press, New York, pp 230–257
Porter JH, Villanueva HF (1989) Assessment of pimozide's motor and hedonic effects on operant behavior in rats. Pharmacol Biochem Behav 31:779–786
Robbins TW (1979) Behavioural determinants of drug action: rate-dependency revisited. In: Cooper SJ (ed) Theory in psychopharmacology, vol 1. Academic Press, London, pp 1–63
Robbins TW, Sahakian BJ (1979) “Paradoxical” effects of psychomotor stimulant drugs from the standpoint of behavioural pharmacology. Neuropharmacology 18:931–950
Sagvolden T, Jenssen JR, Brorson IW (1983) Rate-dependent effects of methylphenidate (Ritalin) on fixed-interval behavior in rats. Scand J Psychol 24:231–236
Sagvolden T, Wultz B, Moser E, Moser M, Morkrid L (1989) Results from a comparative neuropsychological research program indicate altered reinforcement mechanisms in children with ADD. In: Sagvolden T, Archer T (eds) Attention deficit disorder. Erlbaum, Hillsdale, pp 261–286
Tatham TA, Zurn KR (1989) The MED-PC experimental apparatus and programming system. Behav Res Methods Instr Comput 21:294–302
Werry JS, Aman MG (1975) Methylphenidate and haloperidol in children. Arch Gen Psychiatry 32:790–795
Wilkinson GN (1961) Statistical estimation in enzyme kinetics. Biochem J 80:324–332
Williams BA (1988) Reinforcement, choice, and response strength. In: Atkinson RC, Herrnstein RJ, Lindzey G, Luce RD (eds) Stevens' handbook of experimental psychology, vol 2. Learning and cognition, 2nd edn. Wiley, New York, pp 167–244
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Heyman, G.M. Effects of methylphenidate on response rate and measures of motor performance and reinforcement efficacy. Psychopharmacology 109, 145–152 (1992). https://doi.org/10.1007/BF02245492
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02245492