Contributions of the orbitofrontal cortex to impulsive choice: interactions with basal levels of impulsivity, dopamine signalling, and reward-related cues
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Individual differences in impulsive decision-making may be critical determinants of vulnerability to impulse control disorders and substance abuse, yet little is known of their biological or behavioural basis. The orbitofrontal cortex (OFC) has been heavily implicated in the regulation of impulsive decision-making. However, lesions of the OFC in rats have both increased and decreased impulsivity in delay-discounting paradigms, where impulsive choice is defined as the selection of small immediate over larger delayed rewards.
Reviewing the different methods used, we hypothesized that the effects of OFC inactivation on delay discounting may be critically affected by both subjects’ baseline level of impulsive choice and the presence or absence of a cue to bridge the delay between selection and delivery of the large reward.
Here, we show that OFC inactivation increased impulsive choice in less impulsive rats when the delay was cued, but decreased impulsive choice in highly impulsive rats in an uncued condition.
Providing explicit environmental cues to signal the delay-to-reinforcement appears to change the way in which the OFC is recruited in the decision-making process in a baseline-dependent fashion. This change may reflect activation of the dopamine system, as intra-OFC infusions of dopamine receptor antagonists increased impulsive choice but only when the delay was cued.
KeywordsDelay discounting Dopamine Eticlopride Impulsivity Incentive salience SCH 23390 Antagonist Baclofen Muscimol Prefrontal cortex Behaviour Rat
- Bradley C (1937) The behavior of children receiving benzedrine. Am J Psychiat, In, pp 577–585Google Scholar
- Hill RT (ed) (1970) Facilitation of conditioned reinforcement as a mechanism of psychomotor stimulation. Raven, New YorkGoogle Scholar
- Kheramin S, Body S, Mobini S, Ho MY, Velázquez-Martinez DN, Bradshaw CM, Szabadi E, Deakin JF, Anderson IM (2002) Effects of quinolinic acid-induced lesions of the orbital prefrontal cortex on inter-temporal choice: a quantitative analysis. Psychopharmacology (Berl) 165(1):9–17Google Scholar
- Mazur JE (1997) Choice, delay, probability, and conditioned reinforcement. Anim Learn Behav 25:131–147Google Scholar
- Paxinos G, Watson C (1998) The rat brain in stereotaxic co-ordinates. Academic, SydneyGoogle Scholar
- Rogers RD, Everitt BJ, Baldacchino A, Blackshaw AJ, Swainson R, Wynne K, Baker NB, Hunter J, Carthy T, Booker E, London M, Deakin JF, Sahakian BJ, Robbins TW (1999) Dissociable deficits in the decision-making cognition of chronic amphetamine abusers, opiate abusers, patients with focal damage to prefrontal cortex, and tryptophan-depleted normal volunteers: evidence for monoaminergic mechanisms. Neuropsychopharmacol 20:322–339CrossRefGoogle Scholar
- Winstanley CA, Chudasama Y, Dalley JW, Theobald DE, Glennon JC, Robbins TW (2003a) Intra-prefrontal 8-OH-DPAT and M100907 improve visuospatial attention and decrease impulsivity on the five-choice serial reaction time task in rats. Psychopharmacology (Berl) 167:304–314Google Scholar
- Winstanley CA, Theobald DE, Dalley JW, Robbins TW (2005) Interactions between serotonin and dopamine in the control of impulsive choice in rats: therapeutic implications for impulse control disorders. Neuropsychopharmacol 30:669–682Google Scholar