Neuronal correlates of delay discounting in healthy subjects and its implication for addiction: an ALE meta-analysis study

ABSTRACT

Background: Delay discounting (DD) describes the phenomenon of devaluing future rewards in favor of immediate rewards. Increased DD is a key behavioral marker of addiction, and has been suggested as a target for interventions to alleviate addiction symptoms (e.g., preference for immediate drug use over larger-and-later rewards, and relapses) in patients with substance use disorders (SUD).

Objectives: Performed a meta-analysis on neuroimaging results of DD regarding specific contrasts in healthy participants. Reviewed the results of existing patient studies in light of the meta-analyses results.

Methods: We conducted activation likelihood estimation meta-analyses on DD neuroimaging studies (25 studies, n = 583; 354 males and 229 females) regarding six analytic strategies.

Results: The meta-analyses revealed various subdivisions of the cortical-basal ganglia circuits that are associated with different aspects of DD in healthy subjects. By comparing the meta-analyses results and patients’ studies regarding each contrast, we highlighted three brain regions that may underlie excessive DD in patients. Decreased left inferior frontal gyrus (IFG) activity was related to less preference for delayed choices; reduced ventral striatum (VS) activity was associated with impaired valuation processes; and declined anterior cingulate cortex (ACC)/medial prefrontal cortex (mPFC) activity was associated with alterations in processing difficult choices.

Conclusions: We propose that neuromodulation (e.g. deep brain simulation) or behavioral interventions (e.g. episodic future imagination) targeting these key brain regions (IFG, VS, ACC/mPFC) may be effective for improving DD function in patients with SUD, enhancing valuations of future rewards and helping to resist the temptation of immediate drug use.

KEYWORDS:

• Activation likelihood estimation meta-analysis
• substance use disorder
• addiction
• delay discounting
• neuromodulation intervention
• behavioral intervention

Disclosure statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors report no conflicts of interest.

Additional information

Funding

This work was supported by the Walter and Marga Boll Foundation as well as the Institutional Strategy of the University of Cologne within the German Excellence Initiative under Grant number ZUK 81/1; the German Research Council (DFG) under Grant number JE 2707/7-1.