Transforming brain signals related to value evaluation and self-control into behavioral choices

Abstract

The processes involved in value evaluation and self-control are critical when making behavioral choices. However, the evidence linking these two types of processes to behavioral choices in intertemporal decision-making remains elusive. As the ventromedial prefrontal cortex (vmPFC), striatum, and dorsolateral prefrontal cortex (dlPFC) have been associated with these two processes, we focused on these three regions. We employed functional magnetic resonance imaging during a delayed discounting task (DDT) using a relatively large sample size, three independent samples. We evaluated how much information about a specific choice could be decoded from local patterns in each brain area using multivoxel pattern analysis (MVPA). To investigate the relationship between the dlPFC and vmPFC/striatum regions, we performed a psychophysiological interaction (PPI) analysis. In Experiment I, we found that the vmPFC and dlPFC, but not the striatum, could determine choices in healthy participants. Furthermore, we found that the dlPFC showed significant functional connectivity with the vmPFC, but not the striatum, when making decisions. These results could be replicated in Experiment II with an independent sample of healthy participants. In Experiment III, the choice-decoding accuracy in the vmPFC and dlPFC was lower in patients with addiction (smokers and participants with Internet gaming disorder) than in healthy participants, and decoding accuracy in the dlPFC was related to impulsivity in addicts. Taken together, our findings may provide neural evidence supporting the hypothesis that value evaluation and self-control processes both guide the intertemporal choices, and might provide potential neural targets for the diagnosis and treatment of impulsivity-related brain disorders.

Keywords: functional magnetic resonance imaging; intertemporal decision-making; multivoxel pattern analysis; self-control; valuation.

Figure 1

Beta values for subjective value and difficulty level in Experiment I. (a) The mean BOLD signal of the ventromedial prefrontal cortex (vmPFC) and striatum was significantly correlated with the subjective value. The mean BOLD signal of the left dorsolateral prefrontal cortex (dlPFC) was not significantly correlated with the subjective value. (b) The mean BOLD signal of the left dlPFC was significantly correlated with the difficulty level. The mean BOLD signal of the vmPFC and striatum were not significantly correlated with the difficulty level. *Significant at p < .05/3; n.s., not significant; error bars, SEM; SV, subjective value

Figure 2

Decoding the choices from local patterns in all the regions of interest (ROIs) in Experiment I. Healthy participants in Experiment I. *Significant at p < .05/3; n.s., not significant; error bars, SEM

Figure 3

Functional connectivity between dorsolateral prefrontal cortex (dlPFC) and other regions of interest (ROIs) in the value evaluation process when participants selected an option versus baseline during the delayed discounting task (DDT) in Experiment I. *Significant at p < .05/2; n.s., not significant; error bars, SEM

Figure 4

The beta value separately for subjective value as well as difficulty level and for each ROI in Experiment II. (a) The significant regions of interest (ROIs) of subjective value regressor included ventromedial prefrontal cortex (vmPFC) and striatum. The left dorsolateral prefrontal cortex (dlPFC) was not significantly correlated with the subjective value regressor. (b) The significantly activated ROI of difficulty level was the left dlPFC. The vmPFC and striatum was not significantly correlated with difficulty level. *Significant at p < .05; n.s., not significant; error bars, SEM

Figure 5

Decoding the choices from local pattern in all regions of interest (ROIs) in Experiment II. *Significant at p < .05; n.s., not significant; error bars, SEM

Figure 6

Functional connectivity between dorsolateral prefrontal cortex (dlPFC) and other regions of interest (ROIs) in the value evaluation process in Experiment II. *Significant at p < .05; n.s., not significant; error bars, SEM

Figure 7

Group differences on decoding accuracy between Experiments I, II, and III. Compared to the healthy participants in Experiments I and II, participants with Internet‐gaming disorder and smokers in Experiment III showed significantly lower decoding accuracy from the ventromedial prefrontal cortex (vmPFC) and the left dorsolateral prefrontal cortex (dlPFC), respectively. *Significant at p < .05; n.s., not significant; error bars, SEM

Figure 8

Relationship between discounting rate and decoding accuracy from the left dorsolateral prefrontal cortex (dlPFC) in patients with Internet‐gaming disorder and smokers (Experiment III). There was a significant nonlinear relationship between discounting rate and decoding accuracy from the left dlPFC in patients with Internet‐gaming disorder and smokers. Nonlinear relationship suggests that both extremely good and extremely poor decoding accuracy in dlPFC is related to steeper discounting rates. This may demonstrate the complexity of addictive behaviors' effect on the impulsivity, particularly on addictive behaviors' interaction with brain. The discounting rates were normalized by log transformation