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Effect of orexin-B-saporin-induced lesions of the lateral hypothalamus on performance on a progressive ratio schedule

Olarte-Sánchez, Cristian; Valencia Torres, Lourdes; Body, Stephanie; Cassaday, Helen J.; Bradshaw, Chris; Szabadi, Elemer

Authors

Cristian Olarte-Sánchez

Lourdes Valencia Torres

Stephanie Body

Helen J. Cassaday

Chris Bradshaw

Elemer Szabadi



Abstract

It has been suggested that a sub-population of orexinergic neurones whose somata lie in the lateral hypothalamic area (LHA) play an important role in regulating the reinforcing value of both food and drugs. This experiment examined the effect of disruption of orexinergic mechanisms in the LHA on performance on the progressive-ratio schedule of reinforcement, in which the response requirement increases progressively for successive reinforcers. The data were analysed using a mathematical model which yields a quantitative index of reinforcer value and dissociates effects of interventions on motor and motivational processes (Killeen, 1994). Rats were trained under a progressive-ratio schedule using food-pellet reinforcement. They received bilateral injections of conjugated orexin-B-saporin (OxSap) into the LHA or sham lesions. Training continued for a further 40 sessions after surgery. Equations were fitted to the response rate data from each rat, and the parameters of the model were derived for successive blocks of 10 sessions. The OxSap lesion reduced the number of orexin-containing neurones in the LHA by approximately 50% compared to the sham-lesioned group. The parameter expressing the incentive value of the reinforcer was not significantly altered by the lesion. However, the parameter related to the maximum response rate was significantly affected, suggesting that that motor capacity was diminished in the OxSap-lesioned group. The results indicate that OxSap lesions of the LHA disrupted food-reinforced responding on the progressive-ratio schedule. It is suggested that this disruption was brought about by a change in non-motivational (motor) processes.

Journal Article Type Article
Journal Journal of Psychopharmacology
Print ISSN 0269-8811
Electronic ISSN 0269-8811
Publisher SAGE Publications (UK and US)
Peer Reviewed Peer Reviewed
Volume 26
Issue 6
APA6 Citation Olarte-Sánchez, C., Valencia Torres, L., Body, S., Cassaday, H. J., Bradshaw, C., & Szabadi, E. Effect of orexin-B-saporin-induced lesions of the lateral hypothalamus on performance on a progressive ratio schedule. Journal of Psychopharmacology, 26(6), doi:10.1177/0269881111409607
DOI https://doi.org/10.1177/0269881111409607
Publisher URL http://jop.sagepub.com/content/26/6/871.abstract
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf
Additional Information Copyright: Sage

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Olarte_Sanchez,_C.M.,_Valencia_Torres_L.,_Body,_S.,_Cassaday,_H.J.,_Bradshaw,_C.M._&_Szabadi,_E._(2012).pdf (974 Kb)
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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf





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