Assessing Delay Discounting in Mice

Suzanne H. Mitchell1

1 Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon
Publication Name:  Current Protocols in Neuroscience
Unit Number:  Unit 8.30
DOI:  10.1002/0471142301.ns0830s66
Online Posting Date:  January, 2014
GO TO THE FULL TEXT: PDF or HTML at Wiley Online Library


Delay discounting (also intertemporal choice or impulsive choice) is the process by which delayed outcomes, such as delayed food delivery, are valued less than the same outcomes delivered immediately or with a shorter delay. This process is of interest because many psychopathologies, including substance dependence, pathological gambling, attention deficit hyperactivity disorder, and conduct disorder, are characterized by heightened levels of delay discounting. Some of these disorders are heritable, and data indicate that delay discounting also has a genetic component. To identify the genes underlying the delay discounting decision‐making process and genetic correlates of heightened discounting, researchers have used mouse models. This unit describes a protocol for generating delay discounting behavior in mice and discusses analysis techniques for such behavior. Curr. Protoc. Neurosci. 66:8.30.1‐8.30.12. © 2014 by John Wiley & Sons, Inc.

Keywords: intertemporal choice; impulsive choice; decision‐making; subjective value; indifference point; hyperbolic; mouse behavior

PDF or HTML at Wiley Online Library

Table of Contents

  • Introduction
  • Basic Protocol 1: Adjusting Amount Procedure
  • Support Protocol 1: Operant Test Chamber Configuration
  • Support Protocol 2: Software Program Configuration
  • Commentary
  • Literature Cited
  • Figures
  • Tables
PDF or HTML at Wiley Online Library


Basic Protocol 1: Adjusting Amount Procedure

  • Mice, e.g., C57BL/6J from Jackson Laboratories or any other mouse of interest, aged ∼6 weeks on arrival
  • Mouse chow
  • Sucrose solution, e.g., 10% w/v made using store‐bought granulated sugar and tap water
  • Animal housing cages
  • Animal and supplemental food weighing scale
  • Operant test chambers (see protocol 2)
  • Med Associates syringe pumps (motor speed = 3.33 rpm), each containing a syringe (e.g., 10 ml) connected by polyethylene tubes to the liquid food cups of each operant test chamber
  • Med Associates behavioral software (Trans‐IV and Med‐PC version IV) to control the operant test chambers
  • Desktop computer with MS Windows XP
  • Microsoft Excel with Solver Add‐in for data analysis

Support Protocol 1: Operant Test Chamber Configuration

  • Operant test chambers (commercially available, e.g., Med Associates): 15.9 × 14.0 × 12.7 cm (each chamber contains three recesses with head entry detectors and liquid food cups, three yellow LED stimulus lights, clicker module, house light; each chamber should be housed in a ventilated, light‐ and sound‐attenuating cabinet)
  • Med Associates syringe pumps (motor speed = 3.33 rpm), each containing a syringe (e.g., 10 ml) connected by polyethylene tubes to the liquid food cups of each operant test chamber

Support Protocol 2: Software Program Configuration

  • Trans‐IV Program; (Med Associates)
  • Med‐PC IV Program (Med Associates)
  • Desktop computer with MS Windows XP
PDF or HTML at Wiley Online Library



Literature Cited

Literature Cited
   Adriani, W. and Laviola, G. 2003. Elevated levels of impulsivity and reduced place conditioning with d‐amphetamine: Two behavioral features of adolescence in mice. Behav. Neurosci. 117:695‐703.
   Bickel, W.K. , Jarmolowicz, D.P. , Mueller, E.T. , Koffarnus, M.N. , and Gatchalian, K.M. 2012. Excessive discounting of delayed reinforcers as a trans‐disease process contributing to addiction and other disease‐related vulnerabilities: Emerging evidence. Pharmacol. Therapeut. 134:287‐297.
   Cardinal, R.N. , Daw, N. , Robbins, T.W. , and Everitt, B.J. 2002. Local analysis of behaviour in the adjusting‐delay task for assessing choice of delayed reinforcement. Neural Networks 15:617‐634.
   Evenden, J.L. and Ryan, C.N. 1996. The pharmacology of impulsive behaviour in rats: The effects of drugs on response choice with varying delays of reinforcement. Psychopharmacology 128:161‐170.
   Helms, C.M. , Reeves, J.M. , and Mitchell, S.H. 2006. Impact of strain and d‐amphetamine on impulsivity (delay discounting) in inbred mice. Psychopharmacology 188:144‐151.
   Isles, A.R. , Humby, T. , and Wilkinson, L.S. 2003. Measuring impulsivity in mice using a novel operant delayed reinforcement task: Effects of behavioural manipulations and d‐amphetamine. Pharmacology 170:376‐382.
   Isles, A.R. , Humby, T. , Walters, E. , and Wilkinson, L.S. 2004. Common genetic effects on variation in impulsivity and activity in mice. J. Neurosci. 24:6733‐6740.
   Locey, M.L. and Dallery, J. 2011. Nicotine and the behavioral mechanisms of intertemporal choice. Behav. Proc. 87:18‐24.
   Madden, G.J. and Johnson, P.S. 2010. A delay‐discounting primer. In Impulsivity: The Behavioral and Neurological Science of Discounting ( G.J. Madden and W.K. Bickel , eds.) pp. 213‐242. American Psychological Association, Washington, D.C.
   Mazur, J.E. 1987. An adjusting procedure for studying delayed reinforcement. In The Effect of Delay and of Intervening Event on Reinforcement Value. Quantitative Analyses of Behavior ( M.L. Commons , J.E. Mazur , J.A. Nevin , and H. Rachlin , eds.) pp. 55‐73. Lawrence Erlbaum Associates, Hillsdale, N.J.
   Mazur, J.E. 1988. Estimation of indifference points with an adjusting‐delay procedure. J Exp. Anal. Behav. 49:37‐47.
   Mazur, J.E. 2000. Tradeoffs among delay, rate, and amount of reinforcement. Behav. Proc. 49:1‐10.
   Mitchell, S.H. , McCracken, A.D. , Gubner, N.R. , Wilhelm, C.J. , and Phillips, T.J. (in prep.) Genetic Differences in Delay Discounting in Inbred Mouse Strains.
   Myerson, J. , Green, L. , and Warusawitharana, M. 2001. Area under the curve as a measure of discounting. J. Exp. Anal. Behav. 76:235‐243.
   Oberlin, B.G. and Grahame, N.J. 2009. High‐alcohol preferring mice are more impulsive than low‐alcohol preferring mice as measured in the delay discounting task. Alcohol. Clin. Exp. Res. 33:1‐10.
   O'Tousa, D.S. , Matson, L.M. , and Grahame, N.J. 2013. Effects of intoxicating free‐choice alcohol consumption during adolescence on drinking and impulsivity during adulthood in selectively bred high‐alcohol preferring mice. Alcohol. Clin. Exp. Res. 37:141‐149.
   Perry, J.L. and Carroll, M.E. 2008. The role of impulsive behavior in drug abuse. Psychopharmacology 200:1‐26.
   Perry, J.L. , Larson, E.B. , German, J.P. , Madden, G.J. , and Carroll, M.E. 2005. Impulsivity (delay discounting) as a predictor of acquisition of IV cocaine self‐administration in female rats. Psychopharmacology 178:193‐201.
   Rachlin, H. and Green L. 1972. Commitment, choice and self‐control. J. Exp. Anal. Behav. 17:15‐22.
   Richards, J.B. , Mitchell, S.H. , de Wit, H. , and Seiden, L.S. 1997. Determination of discount functions in rats with an adjusting‐amount procedure. J. Exp. Anal. Behav. 67:353‐366.
   Robbins, T.W. , Gillan, C.M. , Smith, D.G. , de Wit, S. , and Ersche, K.D. 2012. Neurocognitive endophenotypes of impulsivity and compulsivity: towards dimensional psychiatry. Trends Cogn. Sci. 16:81‐91.
   Stevens, S.S. 1957. On the psychophysical law. Psychol. Rev. 64:153‐81.
   Wilhelm, C.J. and Mitchell, S.H. 2010. Bias is unaffected by delay length in a delay discounting paradigm. Behav. Proc. 84:445‐49.
PDF or HTML at Wiley Online Library