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Abnormal cognitive effort allocation and its association with amotivation in first-episode psychosis

Published online by Cambridge University Press:  02 October 2019

W. C. Chang ,
A. Westbrook ,
G. P. Strauss ,
A. O. K. Chu ,
C. S. Y. Chong ,
C. M. W. Siu ,
S. K. W. Chan ,
E. H. M. Lee ,
C. L. M. Hui  and
Y. M. Suen
...Show all authors
W. C. Chang*
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong
A. Westbrook
Affiliation:
Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen 6525 EN, The Netherlands Department of Cognitive, Linguistics, and Psychological Sciences, Brown University, Providence, RI02906, USA
G. P. Strauss
Affiliation:
Department of Psychology, University of Georgia, Athens, GA30602, USA
A. O. K. Chu
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong
C. S. Y. Chong
Affiliation:
Department of Psychiatry, Kwai Chung Hospital, Hong Kong
C. M. W. Siu
Affiliation:
Department of Psychiatry, Kwai Chung Hospital, Hong Kong
S. K. W. Chan
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong
E. H. M. Lee
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong
C. L. M. Hui
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong
Y. M. Suen
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong
T. L. Lo
Affiliation:
Department of Psychiatry, Kwai Chung Hospital, Hong Kong
E. Y. H Chen
Affiliation:
Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, Pok Fu Lam, Hong Kong State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong
*
Author for correspondence: W. C. Chang, E-mail: [email protected]
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Abstract

Background

Abnormal effort-based decision-making represents a potential mechanism underlying motivational deficits (amotivation) in psychotic disorders. Previous research identified effort allocation impairment in chronic schizophrenia and focused mostly on physical effort modality. No study has investigated cognitive effort allocation in first-episode psychosis (FEP).

Method

Cognitive effort allocation was examined in 40 FEP patients and 44 demographically-matched healthy controls, using Cognitive Effort-Discounting (COGED) paradigm which quantified participants’ willingness to expend cognitive effort in terms of explicit, continuous discounting of monetary rewards based on parametrically-varied cognitive demands (levels N of N-back task). Relationship between reward-discounting and amotivation was investigated. Group differences in reward-magnitude and effort-cost sensitivity, and differential associations of these sensitivity indices with amotivation were explored.

Results

Patients displayed significantly greater reward-discounting than controls. In particular, such discounting was most pronounced in patients with high levels of amotivation even when N-back performance and reward base amount were taken into consideration. Moreover, patients exhibited reduced reward-benefit sensitivity and effort-cost sensitivity relative to controls, and that decreased sensitivity to reward-benefit but not effort-cost was correlated with diminished motivation. Reward-discounting and sensitivity indices were generally unrelated to other symptom dimensions, antipsychotic dose and cognitive deficits.

Conclusion

This study provides the first evidence of cognitive effort-based decision-making impairment in FEP, and indicates that decreased effort expenditure is associated with amotivation. Our findings further suggest that abnormal effort allocation and amotivation might primarily be related to blunted reward valuation. Prospective research is required to clarify the utility of effort-based measures in predicting amotivation and functional outcome in FEP.

Keywords

Effort discountingeffort-based decision-makingeffort-cost computationmotivational deficitsnegative symptomspsychotic disordersreward valuation
Type
Original Articles
Information
Psychological Medicine , Volume 50 , Issue 15 , November 2020 , pp. 2599 - 2609
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Copyright
Copyright © Cambridge University Press 2019

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Footnotes

*

These authors contributed equally to this article

References

Addington, D, Addington, J, Maticka-Tyndale, E and Joyce, J (1992) Reliability and validity of a depression rating scale for schizophrenics. Schizophrenia Research 6, 201–208.CrossRefGoogle ScholarPubMed
Ahmed, AO, Strauss, GP, Buchanan, RW, Kirkpatrick, B and Carpenter, WT (2015) Are negative symptoms dimensional or categorical? Detection and validation of deficit schizophrenia with taxometric and latent variable mixture models. Schizophrenia Bulletin 41, 879–891.CrossRefGoogle ScholarPubMed
American Psychiatric Association (2000) Diagnostic and Statistical Manual of Mental Disorders, Fourth, Test Revision Edition. Washington DC: American Psychiatric Association.Google Scholar
Bailey, MR, Simpson, EH and Balsam, PD (2016) Neural substrates underlying effort, time, and risk-based decision making in motivated behavior. Neurobiology of Learning and Memory 133, 233–256.CrossRefGoogle ScholarPubMed
Barch, DM, Treadway, MT and Schoen, N (2014) Effort, anhedonia, and function in schizophrenia: reduced effort allocation predicts amotivation and functional impairment. Journal of Abnormal Psychology 123, 387–397.CrossRefGoogle ScholarPubMed
Bates, D, Maechler, M, Bolker, B and Walker, S (2015) Fitting linear mixed-effects models using lme4. Journal of Statistical Software 67, 1–48.CrossRefGoogle Scholar
Bismark, AW, Thomas, ML, Tarasenko, M, Shiluk, AL, Rackelmann, SY, Young, JW and Light, GA (2018) Relationship between effortful motivation and neurocognition in schizophrenia. Schizophrenia Research 193, 69–76.CrossRefGoogle Scholar
Chang, WC, Tang, JY, Hui, CL, Lam, MM, Chan, SK, Wong, GH, Chiu, CP and Chen, EYH (2012) Prediction of remission and recovery in young people presenting with first-episode psychosis in Hong Kong: a 3-year follow-up study. Australian and New Zealand Journal of Psychiatry 46, 100–108.CrossRefGoogle Scholar
Chang, WC, Hui, CLM, Chan, SKW, Lee, EHM and Chen, EYN (2016) Impact of avolition and cognitive impairment on functional outcome in first-episode schizophrenia-spectrum disorder: a prospective one-year follow-up study. Schizophrenia Research 170, 318–321.CrossRefGoogle ScholarPubMed
Chang, WC, Kwong, VWY, Chan, GHK, Jim, OT, Lau, ES, Hui, CL, Chan, SK, Lee, EH and Chen, EYH (2017) Prediction of motivational impairment: 12-month follow-up of the randomized-controlled trial on extended early intervention for first-episode psychosis. European Psychiatry 41, 37–41.CrossRefGoogle ScholarPubMed
Chang, WC, Kwong, VWY, Or, PCF, Lau, ESK, Chan, GHK, Jim, OTT, Hui, CLM, Chan, SKW, Lee, EHM and Chen, EYH (2018 a) Motivational impairment predicts functional remission in first-episode psychosis: 3-year follow-up of the randomized-controlled trial on extended early intervention. Australian and New Zealand Journal of Psychiatry 52, 1194–1201.CrossRefGoogle ScholarPubMed
Chang, WC, Ho, RWH, Tang, JYM, Wong, CSM, Hui, CLM, Chan, SKW, Lee, EMH, Suen, YN and Chen, EYH (2018 b) Early-stage negative symptom trajectories and relationships with 13-year outcomes in first-episode nonaffective psychosis. Schizophrenia Bulletin. doi: 10.1093/schbul/sby115. doi: Epub ahead of print.Google Scholar
Chang, WC, Chu, AOK, Kwong, VWY, Wong, CSM, Hui, CLM, Chan, SKW, Lee, EHM and Chen, EYH (2018 c) Patterns and predictors of trajectories for social and occupational functioning in patients presenting with first-episode non-affective psychosis: a three-year follow-up study. Schizophrenia Research 197, 131–137.CrossRefGoogle ScholarPubMed
Chang, WC, Chu, AOK, Treadway, MT, Strauss, GP, Chan, SKW, Lee, EHM, Hui, CLM, Suen, YN and Chen, EYH (2019) Effort-based decision-making impairment and its relationship with amotivation and functional outcome in first-episode psychosis. European Neuropsychopharmacology 29, 629–642.CrossRefGoogle Scholar
Chong, TTJ, Apps, M, Giehl, K, Sillence, A, Grima, LL and Husain, M (2017) Neurocomputational mechanisms underlying subjective valuation of effort costs. PLoS Biology 15, e1002598.CrossRefGoogle ScholarPubMed
Croxson, PL, Walton, ME, O'Reilly, JX, Behrens, TE and Rushworth, MF (2009) Effort-based cost-benefit valuation and the human brain. Journal of Neuroscience 29, 4531–4541.CrossRefGoogle ScholarPubMed
Culbreth, A, Westbrook, A and Barch, D (2016) Negative symptoms are associated with an increased subjective cost of cognitive effort. Journal of Abnormal Psychology 125, 528–536.CrossRefGoogle ScholarPubMed
Culbreth, AJ, Moran, EK and Barch, DM (2018) Effort-cost decision-making in psychosis and depression: could a similar behavioral deficit arise from disparate psychological and neural mechanisms? Psychological Medicine 48, 889–904.CrossRefGoogle ScholarPubMed
Diller, L, Ben-Yishay, Y, Gerstman, L, Goodkin, R, Gordon, W and Weinberg, J (1974) Studies in Cognition and Rehabilitation in Hemiplegia. Institute of Rehabilitation Medicine Monograph No. 50. New York: New York University Medical Center.Google Scholar
Docx, L, de la Asuncion, J, Sabble, B, Hoste, L, Baeten, R, Warnaerts, N and Morrens, M (2015) Effort discounting and its association with negative symptoms in schizophrenia. Cognitive Neuropsychiatry 20, 172–185.CrossRefGoogle Scholar
Drake, RE, Mueser, KT, McHugo, GJ (1996) Clinician rating scales: alcohol use scale (AUS), drug use scale (DUS), and substance abuse treatment scale (SATS). In Sederer, L and Dickey, B (eds), Outcomes Assessment in Clinical Practice, Williams & Wilkins: Baltimore, MD. pp. 113–116.Google Scholar
Emsley, R, Rabinowitz, J, Torreman, M and Group R-I-EPGW (2003) The factor structure for the Positive and Negative Syndrome Scale (PANSS) in recent-onset psychosis. Schizophrenia Research 61, 47–57.CrossRefGoogle Scholar
Faerden, A, Barrett, EA, Nesvåg, R, Friis, S, Finset, A, Marder, SR, Ventura, J, Andreassen, OA, Agartz, I and Melle, I (2013) Apathy, poor verbal memory and male gender predict lower psychosocial functioning one year after the first treatment of psychosis. Psychiatry Research 210, 55–61.CrossRefGoogle ScholarPubMed
Fervaha, G, Foussias, G, Agid, O and Remington, G (2015 a) Motivational deficits in early schizophrenia: prevalent, persistent, and key determinants of functional outcome. Schizophrenia Research 166, 9–16.CrossRefGoogle ScholarPubMed
Fervaha, G, Duncan, M, Foussias, G, Agid, O, Faulkner, GE and Remington, G (2015 b) Effort-based decision making as an objective paradigm for the assessment of motivational deficits in schizophrenia. Schizophrenia Research 168, 483–490.CrossRefGoogle Scholar
Foussias, G and Remington, G (2010) Negative symptoms in schizophrenia: avolition and Occam's razor. Schizophrenia Bulletin 36, 359–369.CrossRefGoogle ScholarPubMed
Gard, DE, Sanchez, AH, Cooper, K, Fisher, M, Garrett, C and Vinogradov, S (2014) Do people with schizophrenia have difficulty anticipating pleasure, engaging in effortful behavior, or both? Journal of Abnormal Psychology 123, 771–782.CrossRefGoogle Scholar
Gardner, DM, Murphy, AL, O'Donnell, H, Centorrino, F and Baldessarini, RJ (2010) International consensus study of antipsychotic dosing. American Journal of Psychiatry 167, 686–693.CrossRefGoogle ScholarPubMed
Global Burden of Disease Study 2013 Collaborators (2013) Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet 386, 743–800.Google Scholar
Gold, JM, Carpenter, C, Randolph, C, Goldberg, TE and Weinberger, DR (1997) Auditory working memory and Wisconsin Card Sorting Test performance in schizophrenia. Archives of General Psychiatry 54, 159–165.CrossRefGoogle Scholar
Gold, JM, Waltz, JA, Matveeva, TM, Kasanova, Z, Strauss, GP, Herbener, ES, Collins, AG and Frank, MJ (2012) Negative symptoms and the failure to represent the expected reward value of actions. Archives of General Psychiatry 69, 129–138.CrossRefGoogle ScholarPubMed
Gold, JM, Strauss, GP, Waltz, JA, Robinson, BM, Brown, JK and Frank, MJ (2013) Negative symptoms of schizophrenia are associated with abnormal effort-cost computations. Biological Psychiatry 74, 130–136.CrossRefGoogle ScholarPubMed
Gold, JM, Waltz, JA and Frank, MJ (2015 a) Effort cost computation in schizophrenia: a commentary on the recent literature. Biological Psychiatry 78, 747–753.CrossRefGoogle ScholarPubMed
Gold, JM, Kool, W, Botvinick, MM, Hubzin, L, August, S and Waltz, JA (2015 b) Cognitive effort avoidance and detection in people in schizophrenia. Cognitive, Affective & Behavioral Neuroscience 15, 145–154.CrossRefGoogle Scholar
Green, MG, Horan, WP, Barch, DM and Gold, JM (2015) Effort-based decision making: a novel approach for assessing motivation in schizophrenia. Schizophrenia Bulletin 41, 1035–1044.CrossRefGoogle Scholar
Häfner, H, Riecher-Rössler, A, Hambrecht, M, Maurer, K, Meissner, S, Schmidtke, A, Fätkenheuer, B, Löffler, W and van der Heiden, W (1992) IRAOS: an instrument for the assessment of onset and early course of schizophrenia. Schizophrenia Research 6, 209–223.CrossRefGoogle ScholarPubMed
Hartmann, MN, Hager, OM, Reimann, A, Chumbley, JR, Kirschner, M, Seifritz, E, Tobler, PN and Kaiser, S (2015) Apathy but not diminished expression in schizophrenia is associated with discounting of monetary rewards by physical effort. Schizophrenia Bulletin 41, 503–512.CrossRefGoogle Scholar
Hartmann-Riemer, M, Kirschner, M and Kaiser, S (2018) Effort-based decision-making paradigms as objective measures of apathy in schizophrenia? Current Opinion in Behavioral Sciences 22, 70–75.CrossRefGoogle Scholar
Hautus, MJ (1995) Corrections for extreme proportions and their biasing effects on estimated values of d'. Behavior Research Methods, Instruments & Computers 27, 46–51.CrossRefGoogle Scholar
Hernaus, D, Gold, JM, Waltz, JA and Frank, MJ (2018) Impaired expected value computations coupled with overreliance on stimulus-response learning in schizophrenia. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging 3, 916–926.Google Scholar
Horan, WP, Reddy, LF, Barch, DM, Buchanan, RW, Dunayevich, E, Gold, JM, Marder, SR, Wynn, JK, Young, JW and Green, MF (2015) Effort-based decision-making paradigms for clinical trials in schizophrenia: Part 2 – external validity and correlates. Schizophrenia Bulletin 41, 1055–1065.CrossRefGoogle ScholarPubMed
Hosking, JG, Cocker, PJ and Winstanley, CA (2014) Dissociable contributions of anterior cingulate cortex and basolateral amygdala on a rodent cost/benefit decision-making task of cognitive effort. Neuropsychopharmacology 39, 1558–1567.CrossRefGoogle ScholarPubMed
Hosking, JG, Floresco, SB and Winstanley, CA (2015) Dopamine antagonism decreases willingness to expend physical, but not cognitive, effort: a comparison of two rodent cost/benefit decision-making tasks. Neuropsychopharmacology 40, 1005–1015.CrossRefGoogle Scholar
Howes, OD, Kambeitz, J, Kim, E, Stahl, D, Slifstein, M, Abi-Dargham, A and Kapur, S (2012) The nature of dopamine dysfunction in schizophrenia and what this means for treatment. JAMA Psychiatry 69, 776–786.Google ScholarPubMed
Hong Kong Psychological Society (1989 a) The Wechsler Adult Intelligence Scale-Revised (Cantonese Version). Hong Kong: Hong Kong Psychological Society.Google Scholar
Hong Kong Psychological Society (1989 b) The Wechsler Adult Memory Scale-Revised (Cantonese Version). Hong Kong: Hong Kong Psychological Society.Google Scholar
Kay, SR, Fiszbein, A and Opler, LA (1987) The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophrenia Bulletin 13, 261–276.CrossRefGoogle Scholar
Kirkpatrick, B, Strauss, GP, Nguyen, L, Fischer, BA, Daniel, DG, Cienfuegos, A and Marder, SR (2011) The Brief Negative Symptom Scale: psychometric properties. Schizophrenia Bulletin 37, 300–305.CrossRefGoogle ScholarPubMed
Lutgens, D, Joober, R, Iyer, S, Lepage, M, Norman, R, Schmitz, N, Mustafa, S, Abadi, S and Malla, A (2019) Progress of negative symptoms over the first 5 years of a first episode of psychosis. Psychological Medicine 49, 66–74.CrossRefGoogle ScholarPubMed
McCarthy, JM, Treadway, MT, Bennett, ME and Blanchard, JJ (2016) Inefficient effort allocation and negative symptoms in individuals with schizophrenia. Schizophrenia Research 170, 278–284.CrossRefGoogle ScholarPubMed
Messinger, JW, Tremeau, F and Antonius, D (2011) Avolition and expressive deficits capture negative symptom phenomenology: implications for DSM-5 and schizophrenia research. Clinical Psychology Review 31, 161–168.CrossRefGoogle ScholarPubMed
Minzenberg, MJ, Laird, AR, Thelen, S, Carter, CS and Glahn, DC (2009) Meta-analysis of 41 functional neuroimaging studies of executive function in schizophrenia. Archives of General Psychiatry 66, 811–822.CrossRefGoogle Scholar
Moran, EK, Culbreth, AJ and Barch, DM (2017) Ecological momentary assessment of negative symptoms in schizophrenia: relationships to effort-based decision making and reinforcement learning. Journal of Abnormal Psychology 126, 96–105.CrossRefGoogle ScholarPubMed
Norman, RMG, Manchanda, R, Harricharan, R and Northcott, S (2015) The course of negative symptoms over the first five years of treatment: data from an early intervention program for psychosis. Schizophrenia Research 169, 412–417.CrossRefGoogle Scholar
R Core Team (2018) R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing. Available at https://www.R-project.org/.Google Scholar
Reddy, LF, Horan, WP, Barch, DM, Buchanan, RW, Dunayevich, E, Gold, JM, Lyons, N, Marder, SR, Treadway, MT, Wynn, JK, Young, JW and Green, MF (2015) Effort-based decision-making paradigms for clinical trials in schizophrenia: Part 1 – psychometric characteristics of 5 paradigms. Schizophrenia Bulletin 41, 1045–1054.CrossRefGoogle ScholarPubMed
Reddy, LF, Horan, WP, Barch, DM, Buchanan, RW, Gold, JM, Marder, SR, Wynn, JK, Young, J and Green, MF (2018) Understanding the association between negative symptoms and performance on effort-based decision-making tasks: the importance of defeatist performance beliefs. Schizophrenia Bulletin 44, 1217–1226.CrossRefGoogle ScholarPubMed
Reitan, RM (1955) The relation of the Trail Making Test to organic brain damage. Journal of Counseling Psychology 10, 330–340.Google Scholar
Salamone, JD, Correa, M, Nunes, EJ, Randall, PA and Pardo, M (2012) The behavioral pharmacology of effort-related choice behavior: dopamine, adenosine and beyond. Journal of the Experimental Analysis of Behavior 97, 125–146.CrossRefGoogle ScholarPubMed
Schmidt, L, Lebreton, M, Clery-Melin, ML, Daunizeau, J and Pessiglione, M (2012) Neural mechanisms underlying motivation of mental versus physical effort. PLoS Biololgy 10, e1001266.CrossRefGoogle ScholarPubMed
Serper, M, Payne, E, Dill, C, Portillo, C and Taliercio, J (2017) Allocating effort in schizophrenia: relation to negative symptoms, working memory, reward anticipation and real world functioning. European Psychiatry 46, 57–64.CrossRefGoogle Scholar
Simpson, GM and Angus, JW (1970) A rating scale for extrapyramidal side effects. Acta Psychiatrica Scandnavica 212(Suppl.), 11–19.CrossRefGoogle ScholarPubMed
So, E, Kam, I, Leung, CM, Chung, D, Liu, Z and Fong, S (2003) The Chinese-bilingual SCID-I/P Project: Stage 1: reliability for mood disorders and schizophrenia. Hong Kong Journal of Psychiatry 13, 7–18.Google Scholar
Strauss, GP, Hong, LE, Gold, JM, Buchanan, RW, McMahon, RP, Keller, WR, Fischer, BA, Catalano, LT, Culbreth, AJ, Carpenter, WT and Kirkpatrick, B (2012) Factor structure of the brief negative symptom scale. Schizophrenia Research 142, 96–98.CrossRefGoogle ScholarPubMed
Strauss, GP, Whearty, KM, Morra, LF, Sullivan, SK, Ossenfort, KL and Frost, KH (2016) Avolition in schizophrenia is associated with reduced willingness to expend effort for reward on a Progressive Ratio task. Schizophrenia Research 170, 198–204.CrossRefGoogle ScholarPubMed
Treadway, MT, Buckholtz, JW, Schwartzman, AN, Lambert, WE and Zald, DH (2009) Worth the ‘EEfRT?’ The effort expenditure for rewards tasks as an objective measure of motivation and anhedonia. PLoS ONE 4, e6598.CrossRefGoogle Scholar
Treadway, MT, Peterman, JS, Zald, DH and Park, S (2015) Impaired effort allocation in patients with schizophrenia. Schizophrenia Research 161, 382–385.CrossRefGoogle ScholarPubMed
Verma, S, Subramaniam, M, Abdin, E, Poon, LY and Chong, SA (2012) Symptomatic and functional remission in patients with first-episode psychosis. Acta Psychiatrica Scandinavica 126, 282–289.CrossRefGoogle ScholarPubMed
Ventura, J, Subotnik, KL and Gitlin, MJ (2015) Negative symptoms and functioning during the first year after a recent onset of schizophrenia and 8 years later. Schizophrenia Research 161, 407–413.CrossRefGoogle ScholarPubMed
Waltz, JA and Gold, JM (2016) Motivational deficits in schizophrenia and the representation of expected value. Current Topics in Behavioral Neurosciences 27, 375–410.CrossRefGoogle ScholarPubMed
Wang, J, Huang, J, Yang, X, Lui, SSY, Cheung, EFC and Chan, RCK (2015) Anhedonia in schizophrenia: deficits in both motivation and hedonic capacity. Schizophrenia Research 168, 465–474.CrossRefGoogle ScholarPubMed
Wardle, MC, Treadway, MT, Mayo, LM, Zald, DH and de Wit, H (2011) Amping up effort: effects of d-amphetamine on human effort-based decision-making. Journal of Neuroscience 31, 16597–16602.CrossRefGoogle ScholarPubMed
Westbrook, A and Braver, TS (2015) Cognitive effort: a neuroeconomic approach. Cognitive, Affective & Behavioral Neuroscience 15, 395–415.CrossRefGoogle ScholarPubMed
Westbrook, A, Kester, D and Braver, TS (2013) What is the subjective cost of cognitive effort? Load, trait, and aging effects revealed by economic preference. PLoS ONE 7, e68210.CrossRefGoogle Scholar
Wolf, DH, Satterthwaite, TD, Kantrowitz, JJ, Katchmar, N, Vandekar, L, Elliott, MA and Ruparel, K (2014) Amotivation in schizophrenia: integrated assessment with behavioral, clinical, and imaging measures. Schizophrenia Bulletin 40, 1328–1337.CrossRefGoogle ScholarPubMed
Young, JW and Markou, A (2015) Translational rodent paradigms to investigate neuromechanisms underlying behaviors relevant to amotivation and altered reward processing in schizophrenia. Schizophrenia Bulletin 41, 1024–1034.CrossRefGoogle Scholar
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