The neural substrates responsible for how trait anxiety affects delay discounting: Right hippocampal and cerebellar connectivity with bistable right inferior parietal lobule

Abstract

Delay discounting, an indicator of impulsivity, refers to the extent of devaluing future rewards. Studies have found that individuals with trait anxiety generally depreciate the later larger rewards, showing steeper delay discounting rates. However, little is known about the neural substrates responsible for how trait anxiety affects individuals' delay discounting. To address this question, we employed the voxel‐based morphometry (VBM) and resting‐state functional connectivity (RSFC) methods to explore the neural substrates of trait anxiety responsible for delay discounting. Behavioral results showed that trait anxiety was significantly positively correlated with delay discounting rates. The VBM analysis revealed that gray matter volumes of the right hippocampus (RHPC) and right cerebellum (RCere) were significantly positively correlated with trait anxiety. Moreover, the RSFC results showed that bistable right inferior parietal lobule (RIPL) connectivity with the RHPC and RCere were all inversely associated with trait anxiety. More importantly, mediation analysis indicated that trait anxiety played a completely mediating role in the relation between functional connectivity of RHPC‐RIPL and RCere‐RIPL and delay discounting. These results suggested that bistable RIPL connectivity with RHPC and RCere could be neural substrates underlying the effect of trait anxiety on delay discounting. On the whole, the current study yields insights into how trait anxiety affects delay discounting and provides a novel account from a neural basis perspective.

The effect of trait anxiety on risk‐taking: Functional coupling between right hippocampus and left insula

“…T-AI is widely used and suitable for calculating individual's level of trait anxiety. It has been shown to be reliable and valid to use on a Chinese population with a Cronbach's alpha of 0.875 in previous research (Zhang et al, 2019) and 0.855 in the present study. The higher the total score the more likely it is that the subject is prone to anxiety.…”

“…The hippocampus has also been related to functions involved in episodic prospective memory (Race, Keane, & Verfaellie, 2013;Schacter, Addis, & Buckner, 2007) for making decisions about future potential outcomes. Those with high trait anxiety may depreciate the future outcomes and be susceptible to negatively anticipating future possibilities (Miloyan, Bulley, & Suddendorf, 2016;Zhang, Chen, Liu, & Feng, 2019). Consistent with this role in episodic prospective memory, Zhang et al (2019) found hippocampal anatomical differences related to trait anxiety and the effects of trait anxiety on intertemporal choice (deciding whether to take a smaller earlier option or waiting for a larger later reward).…”

“…Given these characteristics of the task, we predicted that trait anxiety scores would be negatively related to risk-taking. To identify the neural mechanism responsible for the influence of trait anxiety on risk-taking, we focused on a region of right hippocampus (RHPC), which was associated with trait anxiety in a previous voxel-based morphometry (VBM) study (Zhang et al, 2019) as well as in our sample. We examined the functional connectivity between a RHPC seed and the rest of the brain, and found that RHPC-LInsula connectivity was related to both trait anxiety and risk-taking.…”

“…Following Zhang et al (2019), multiple linear regression was performed with trait anxiety as the variable of interest in SPM12. Global GM volumes were calculated using a MATLAB script "get_totals" and deemed as covariates of no interest (http://www.cs.ucl.ac.uk/staff /g.ridgw ay/vbm/ get_totals.m).…”

“…The functional connectivity analyses were performed using the REST toolbox environment (Song et al, 2011). We defined a right hippocampus (RHPC) seed region based on the study of (Zhang et al, 2019), and confirmed by the VBM analyses performed on our sample. This seed region is illustrated in Figure 1.…”