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Oxygen responses within the nucleus accumbens are associated with individual differences in effort exertion in rats
Author(s) -
Hailwood Jonathan M.,
Gilmour Gary,
Robbins Trevor W.,
Saksida Lisa M.,
Bussey Timothy J.,
Marston Hugh M.,
Gastambide Francois
Publication year - 2018
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14150
Subject(s) - nucleus accumbens , psychology , neuroscience , oxygen , brain mapping , functional magnetic resonance imaging , chemistry , central nervous system , organic chemistry
Goal‐directed motivated behaviour is crucial for everyday life. Such behaviour is often measured, in rodents, under a progressive ratio (PR) schedule of reinforcement. Previous studies have identified a few brain structures critical for supporting PR performance. However, the association between neural activity within these regions and individual differences in effort‐related behaviour is not known. Presently, we used constant potential in vivo oxygen amperometry, a surrogate for functional resonance imaging in rodents, to assess changes in tissue oxygen levels within the nucleus accumbens ( NA c) and orbitofrontal cortex ( OFC ) in male Wistar rats performing a PR task. Within both regions, oxygen responses to rewards increased as the effort exerted to obtain the rewards was larger. Furthermore, higher individual breakpoints were associated with greater magnitude NA c oxygen responses. This association could not be explained by temporal confounds and remained significant when controlling for the different number of completed trials. Animals with higher breakpoints also showed greater magnitude NA c oxygen responses to rewards delivered independently of any behaviour. In contrast, OFC oxygen responses were not associated with individual differences in behavioural performance. The present results suggest that greater NA c oxygen responses following rewards, through a process of incentive motivation, may allow organisms to remain on task for longer and to overcome greater effort costs.