The neural substrates responsible for punishment sensitivity association with procrastination: Left putamen connectivity with left middle temporal gyrus

Procrastination has adverse consequences across cultural contexts. Behavioral research found a positive correlation between punishment sensitivity and procrastination. However, little is known about the neural substrates underlying the association between them. We employed voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) methods to address this issue with two independent samples. In Sample 1, behavioral results found that punishment sensitivity was positively related to procrastination. The VBM analysis showed that punishment sensitivity was negatively correlated with gray matter volume in left putamen. Subsequently, the RSFC results revealed that left putamen - left middle temporal gyrus (MTG) connectivity was positively associated with punishment sensitivity. More crucially, mediation analysis indicated that left putamen - left MTG connectivity mediated the relationship between punishment sensitivity and procrastination. The aforementioned results were validated in Sample 2. Altogether, left putamen - left MTG connectivity might be the neural signature of the association between punishment sensitivity and procrastination.

The functional connectivity between right parahippocampal gyrus and precuneus underlying the association between reward sensitivity and procrastination

Procrastination has adverse effects on personal growth and social development. Behavior research has found reward sensitivity is positively correlated with procrastination. However, it remains unclear that the neural substrates underlie the relationship between reward sensitivity and procrastination. To address this issue, the present study used voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) analyses to investigate the neural substrates underlying the association with reward sensitivity and procrastination in two independent samples (N1 = 388, N2 = 330). In Sample 1, the behavioral result indicated reward sensitivity was positively correlated with procrastination. Moreover, the VBM analysis showed that reward sensitivity was positively associated with the gray matter volume (GMV) of the right parahippocampal gyrus. Furthermore, the RSFC result found reward sensitivity was negatively associated with the functional connectivity of the right parahippocampal gyrus-precuneus. Crucially, the mediation analysis revealed that functional connectivity of the right parahippocampal gyrus-precuneus mediated the relationship between reward sensitivity and procrastination. To verify the robustness of the results, confirmatory analysis was carried out in Sample 2. The results of Sample 1 (i.e., the behavioral, VBM, RSFC, and mediation results) can be verified in Sample 2. In brief, these findings suggested that the functional connectivity of the right parahippocampal gyrus-precuneus involved in reward impulsive control could modulate the relationship between reward sensitivity and procrastination, which is the first to reveal the neural underpinning of the association between reward sensitivity and procrastination.

Frontostriatal Functional Connectivity Underlies the Association between Punishment Sensitivity and Procrastination

Procrastination is defined as putting off an intended course of action voluntarily despite the harmful consequences. Previous studies have suggested that procrastination is associated with punishment sensitivity in that high punishment sensitivity results in increased negative utility for task performance. We hypothesized the effects of punishment sensitivity on procrastination would be mediated by a network connecting the caudate nucleus and prefrontal cortex, both of which have been previously associated with self-control and emotional control during procrastination. We employed voxel-based morphometry (VBM) and resting-state functional connectivity (rsFC) to examine the neural substrates of punishment sensitivity and its relationship with procrastination (N = 268). The behavioral results indicated a strong positive correlation between measures of punishment sensitivity and procrastination. The VBM analysis revealed that the gray matter (GM) volume of the right caudate was significantly positively correlated with punishment sensitivity. The primary rsFC analysis revealed connectivity between this caudate location and the bilateral middle frontal gyrus (MFG) was significantly negatively correlated with punishment sensitivity. A mediation model indicated punishment sensitivity completely mediated the relation between functional connectivity within a caudate–bilateral MFG network and procrastination. Our results support the theory that those with higher punishment sensitivity have weaker effective emotional self-control supported by the caudate–MFG network, resulting in greater procrastination.