Format

Send to

Choose Destination
Front Behav Neurosci. 2018 Dec 13;12:312. doi: 10.3389/fnbeh.2018.00312. eCollection 2018.

Nigrostriatal Dopaminergic Denervation Does Not Promote Impulsive Choice in the Rat: Implication for Impulse Control Disorders in Parkinson's Disease.

Author information

1
INSERM U1216 and Univ. Grenoble Alpes, Grenoble Institut des Neurosciences (GIN), Grenoble, France.
2
CIC-INSERM 1402, Service de Neurologie, CHU de Poitiers, Université de Poitiers, Poitiers, France.
3
Department of Psychology, Faculty of Biology, University of Cambridge, Cambridge, United Kingdom.

Abstract

Impulse control disorders (ICDs) are frequent behavioral complications of dopaminergic (DA) replacement therapies (DRTs) in Parkinson's disease (PD). Impulsive choice, which refers to an inability to tolerate delays to reinforcement, has been identified as a core pathophysiological process of ICDs. Although impulsive choices are exacerbated in PD patients with ICDs under DRTs, some clinical and preclinical studies suggest that the DA denervation of the dorsal striatum induced by the neurodegenerative process as well as a pre-existing high impulsivity trait, may both contribute to the emergence of ICDs in PD. We therefore investigated in a preclinical model in rats, specifically designed to study PD-related non-motor symptoms, the effect of nigrostriatal DA denervation on impulsive choice, in relation to pre-existing levels of impulsivity, measured in a Delay Discounting Task (DDT). In this procedure, rats had the choice between responding for a small sucrose reinforcer delivered immediately, or a larger sucrose reinforcer, delivered after a 0, 5, 10 or 15 s delay. In two different versions of the task, the preference for the large reinforcer decreased as the delay increased. However, and in contrast to our initial hypothesis, this discounting effect was neither exacerbated by, or related to, the extent of the substantia nigra pars compacta (SNc) DA lesion, nor it was influenced by pre-existing variability in impulsive choice. These results therefore question the potential implication of the nigrostriatal DA system in impulsive choice, as well as the DA neurodegenerative process as a factor contributing significantly to the development of ICDs in PD.

KEYWORDS:

6-OHDA; Parkinson’s disease; delay discounting task; dopaminergic nigrostriatal system; impulse control disorders; impulsive choice; rats

Supplemental Content

Full text links

Icon for Frontiers Media SA Icon for PubMed Central
Loading ...
Support Center