Neural substrates underlying balanced time perspective: A combined voxel-based morphometry and resting-state functional connectivity study

Behavioral genetics of temporal framing: Heritability of time perspective and its common genetic bases with major personality traits

OBJECTIVE

The present study aimed to provide a seminal behavioral genetic analysis of time perspectives (TPs). Moreover, we intended to investigate the magnitude of genetic vs. environmental components of the well-established assocations between TPs and personality features.

BACKGROUND

Individual differences in temporal framing processes, referred to as TPs, are vital psychological and behavioral outcomes. Although proponents of TP theory emphasize mainly environmental origins of the tendencies to adopt certain TPs, research provides evidence for marked associations between the temporal dimensions and major personality traits that are known to be heritable. Hence, it was essential to empirically verify these claims.

METHOD

The article reports an analysis of genetic and environmental components of variance in TPs based on a study adopting a twin design, conducted on a sample of 393 pairs of twins (135 monozygotic and 258 dizygotic).

RESULTS

Multivariate Cholesky decomposition supported an EA model assuming impacts of both unshared environmental factors (E) and additive genetic factors (A) across all TP dimensions, suggesting that the effects of shared environment on TPs are plausibly negligible. Heritability indices of TPs ranged between 0.51 for Present-Fatalistic and 0.62 for Present-Hedonistic, suggesting that the majority of the variance in TPs stems from genetic influences. Substantial genetic correlations were found between TPs and the Big Five personality traits.

CONCLUSIONS

The findings provide further evidence for conceptualizing TPs as biologically based personality traits and challenge the claims that TP is mainly a product of culture, education, and personal experiences.

How the intrinsic functional connectivity patterns of the semantic network support semantic processing

Semantic processing, a core of language comprehension, involves the activation of brain regions dispersed extensively across the frontal, temporal, and parietal cortices that compose the semantic network. To comprehend the functional structure of this semantic network and how it prepares for semantic processing, we investigated its intrinsic functional connectivity (FC) and the relation between this pattern and semantic processing ability in a large sample from the Human Connectome Project (HCP) dataset. We first defined a well-studied brain network for semantic processing, and then we characterized the within-network connectivity (WNC) and the between-network connectivity (BNC) within this network using a voxel-based global brain connectivity (GBC) method based on resting-state functional magnetic resonance imaging (fMRI). The results showed that 97.73% of the voxels in the semantic network displayed considerably greater WNC than BNC, demonstrating that the semantic network is a fairly encapsulated network. Moreover, multiple connector hubs in the semantic network were identified after applying the criterion of WNC > 1 SD above the mean WNC of the semantic network. More importantly, three of these connector hubs (i.e., the left anterior temporal lobe, angular gyrus, and orbital part of the inferior frontal gyrus) were reliably associated with semantic processing ability. Our findings suggest that the three identified regions use WNC as the central mechanism for supporting semantic processing and that task-independent spontaneous connectivity in the semantic network is essential for semantic processing.

Effects of COVID-19 event intensity on college students' health lifestyles: time perspective mediating model and its gender difference

The pandemic of COVID-19 had not only led to healthy-damage behaviors, but also raised people's attention to health and generated health-promoting behaviors. However, little is known about the mechanism underlying how the perception of COVID-19 intensity affects health behaviors. The present study investigated the mediating effect of DBTP between event intensity and health behaviors and the moderating role of gender in this relation. Nine hundred and twenty-four Chinese college students (348 males and 576 females) completed a battery of self-report questionnaires, including COVID-19 Event Intensity Scale, Chinese version of Zimbardo Time Perspective Inventory (ZTPI) and Healthy Lifestyle Scale. Moderated mediation analysis was performed using conditional process analysis. The results showed that COVID-19 intensity had a positive predictive effect on college students' health behaviors. DBTP played a partial mediating role in the relationship between COVID-19 intensity and health behaviors for male and not female. In female group, COVID-19 intensity and DBTP was significantly linked with health behaviour; however, COVID-19 intensity and DBTP were not significantly linked. The findings indicated that COVID-19 intensity perceived by college students could increase their health behaviors, and intervention focus on BTP may contribute to health behaviors only in male. Practical implications were discussed in this academic research.

Functional Coupling between the Fronto-Parietal Network and Default Mode Network Is Associated with Balanced Time Perspective

Balanced time perspective refers to the ability to flexibly switch between different temporal foci in an adaptive manner according to the current context. Functional connectivity within the default mode network (DMN) has been suggested to support balanced time perspective. The coupling between the DMN and fronto-parietal network (FPN) may drive many important expressions of internally directed cognition. However, it remains unclear whether balanced time perspective is supported by the interaction between the FPN and DMN. To examine these issues, we recruited 91 participants (52 males with mean age of 19.6, and 39 females with mean age of 20.0) to undergo resting-state brain imaging scan and to complete a questionnaire measuring balanced time perspective. Seed-based voxel-wise functional connectivity analyses implicated midline DMN regions including the anterior medial prefrontal cortex (amPFC) and posterior cingulate cortex (PCC) along with the anterior cingulate cortex (ACC), precuneus, and cerebellum in supporting a balanced time perspective. More importantly, functional connectivity between the right amPFC and right dorsal lateral prefrontal cortex (DLPFC) in the FPN was found to associate with balanced time perspective. Our findings suggest the importance of coordinated brain activity in supporting a balanced time perspective.

The neural substrates of sex differences in balanced time perspective: A unique role for the precuneus

Sex differences in various aspects of behaviour and cognition have been widely observed. Few studies, however, have explored potential sex differences in maintaining a balanced time perspective or their underlying neural correlates. To address these questions, two studies were conducted. In Study 1, time perspective was assessed in 1913 college students (796 males and 1117 females), revealing that females had a significantly more balanced time perspective relative to males. In Study 2, 58 males and 47 females underwent an assessment of time perspective and structural brain imaging. Voxel-based morphometry analysis and cortical thickness analysis were conducted to explore associations between the structural imaging data and balanced time perspective. Compared with males, females demonstrated a more balanced time perspective in the context of lower grey matter volume in the bilateral precuneus, right cerebellum, right putamen and left supplementary motor area. Analysis of cortical thickness failed to reveal any significant sex differences. Furthermore, lower grey matter volume of bilateral precuneus was associated with more balanced time perspective among all participants. Our findings point to a critical role for the precuneus in modulating a balanced time perspective, and extend our understanding of sex differences in human cognition. Future studies are required to determine whether sex differences in balanced time perspective are predictive of functional outcomes in daily life.

Human time perspective and its structural associations with voxel-based morphometry and gyrification

Time perspective refers to humans' concept of integrating and evaluating temporal position and evaluation of memories, emotions, and experiences. We tested the hypothesis that different aspects of time perspective, as assessed with the Zimbardo Time Perspective Inventory (ZTPI) are related to variation of brain structure in non-clinical subjects. Analysing data from n = 177 psychiatrically healthy subjects using voxel-based morphometry with the CAT12 software package, we identified several significant (p < 0.05 FWE, cluster-level corrected) associations. The factors past negative, reflecting a negative attitude towards past events and present fatalistic, measuring a hopeless and fatalistic attitude towards future life, were both negatively associated with grey matter volumes of the anterior insula. The ZTPI factor future was negatively associated with precuneus grey matter. There was no association of ZTPI scores with gyrification using an absolute mean curvature method, a marker of early brain development. These findings provide a link between a general psychological construct of time perspective and brain structural variations in key areas related to time keeping (anterior insula) and the default mode network (precuneus), both of which overlap with variation in behavioral aspects and psychopathology.

The Neural Basis Linking Achievement Motivation With Procrastination: Left Precuneus Connectivity With Right Anterior Cingulate Cortex

Procrastination adversely affects individual's learning, working, health, and well-being, which troubles many people around the world. Previous studies have indicated that people with higher achievement motivation tend to have less procrastination. However, how achievement motivation is linked with procrastination at the neural level is still poorly understood. Here, we adopted the voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) methods to study this issue. The VBM analysis revealed that higher achievement motivation was correlated with larger gray matter volumes in left precuneus (lPre). Furthermore, the RSFC results showed that the functional connectivity between lPre and right anterior cingulate cortex (rACC) was positively associated with achievement motivation and negatively correlated with procrastination. More importantly, a mediation analysis demonstrated that achievement motivation fully mediated the relation between lPre-rACC connectivity and procrastination. These findings suggested that lPre-rACC coupling might be the neural correlate underlying the association between achievement motivation and procrastination.

Nocturnal Hypoxemia Is Associated with Altered Parahippocampal Functional Brain Connectivity in Older Adults at Risk for Dementia

BACKGROUND

Obstructive sleep apnea is associated with an increased risk of developing mild cognitive impairment and dementia. Intermittent nocturnal hypoxemia in obstructive sleep apnea is associated with brain changes in key regions that underpin memory.

OBJECTIVE

To determine whether older adults with severe nocturnal hypoxemia would exhibit reduced functional connectivity within these regions, with associated deficits in memory.

METHODS

Seventy-two participants 51 years and over underwent polysomnography with continuous blood oxygen saturation recorded via oximetry. The oxygen desaturation index (ODI, 3% dips in oxygen levels per hour) was the primary outcome measure. ODI was split into tertiles, with analyses comparing the lowest and highest tertiles (N = 48). Thirty-five of the 48 participants from these two tertiles had mild cognitive impairment. Participants also underwent resting-state fMRI and comprehensive neuropsychological, medical, and psychiatric assessment.

RESULTS

The highest ODI tertile group demonstrated significantly reduced connectivity between the left and right parahippocampal cortex, relative to the lowest ODI tertile group (t(42) = -3.26, p = 0.041, beta = -1.99).The highest ODI tertile group also had poorer working memory performance. In the highest ODI tertile group only, higher left-right parahippocampal functional connectivity was associated with poorer visual memory recall (between-groups z = -2.93, p = 0.0034).

CONCLUSIONS

Older adults with severe nocturnal hypoxemia demonstrate impaired functional connectivity in medial temporal structures, key regions involved in sleep memory processing and implicated in dementia pathophysiology. Oxygen desaturation and functional connectivity in these individuals each relate to cognitive performance. Research is now required to further elucidate these findings.

The preference for future outcomes correlates with the temporal variability of functional connectivity among brain regions

People inevitably make decisions between short-term and long-term consequences across domains like education, health and economics. In this kind of decision, the tendency to discount the value of later-larger rewards with increasing delays is defined as delay discounting (DD). A recent review has suggested that three neural systems which respectively responsible for valuation, prospection and cognitive control (e.g., ventromedial prefrontal cortex [vmPFC], hippocampus, precuneus and dorsolateral prefrontal cortex [dlPFC]) could interact with each other flexibly to have impacts on DD. However, to date, there is little attention paid on the connection between the DD and the dynamic interaction of brain regions.To tackle this issue, we investigate the relationship between the DD and the time-varying connectivity among brain regions in two samples of young adults. Results in sample 1 found that the DD was negatively correlated with the temporal variability of functional connectivity [FC] between the vmPFC and precuneus, and between the vmPFC and the left superior frontal gyrus. And the temporal variabilities of FC between the ventral striatum and right dlPFC, and between the ventral striatum and dorsomedial prefrontal cortex were also negatively related to DD. Furthermore, the main results were well replicated and validated in another sample using different analysis parameters. Overall, our findings reveal that temporal fluctuation of FC within default mode and fronto-striatal circuits can favor for prospecting future, cognitive control and valuation of delayed incentives, and this flexible connectivity patterns generally have association with preference for future outcomes.

High Self-Control Reduces Risk Preference: The Role of Connectivity Between Right Orbitofrontal Cortex and Right Anterior Cingulate Cortex

Risk preference, the preference for risky choices over safe alternatives, has a great impact on many fields, such as physical health, sexual safety and financial decision making. Ample behavioral research has attested that inadequate self-control can give rise to high risk preference. However, little is known about the neural substrates underlying the effect of self-control on risk preference. To address this issue, we combined voxel-based morphometry (VBM) with resting-state functional connectivity (RSFC) analyses to explore the neural basis underlying the effect of self-control on risk preference across two independent samples. In sample 1 (99 participants; 47 males; 20.37 ± 1.63 years), the behavioral results indicated that the scores of self-control were significantly and negatively correlated with risk preference (indexed by gambling rate). The VBM analyses demonstrated that the higher risk preference was correlated with smaller gray matter volumes in right orbitofrontal cortex (rOFC) and right posterior parietal cortex. In the independent sample 2 (80 participants; 33 males; 20.33 ± 1.83 years), the RSFC analyses ascertained that the functional connectivity of rOFC and right anterior cingulate cortex (rACC) was positively associated with risk preference. Furthermore, the mediation analysis identified that self-control mediated the impact of functional connectivity of rOFC-rACC on risk preference. These findings suggest the functional coupling between the rOFC and rACC might account for the association between self-control and risk preference. The present study extends our understanding on the relationship between self-control and risk preference, and reveals possible neural underpinnings underlying this association.

Neural bases underlying the association between balanced time perspective and trait anxiety

The aims of present study were to investigate the association between balanced time perspective (BTP) and trait anxiety, and the neural substrates underlying this association using voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) methods. 140 college students (83 females) ranging in age from 17 to 25 years were assessed on deviation from the balanced time perspective (DBTP) and trait anxiety. Behavioral analyses found BTP could significantly predict trait anxiety after controlling age and gender. Whole-brain VBM analyses found that DBTP was positively correlated with gray matter volume (GMV) in the parahippocampal gyrus (PHG) and precuneus, while trait anxiety positively correlated with GMV in the PHG. Considering the overlapping region in the PHG, we further defined the overlapping region as the seed, and calculated seed-to-voxel-based functional connectivity in resting-state. RSFC results showed that DBTP was positively associated with the RSFC between the PHG and medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and precuneus, whereas negatively correlated with the RSFC between the PHG and cuneus. Trait anxiety was also positively correlated with the RSFC between the PHG and PCC while negatively correlated with the RSFC between the PHG and cuneus. Mediation analysis further found GMV in the overlapping PHG and PHG-PCC, PHG-cuneus functional connectivity played significantly mediating roles in the relation between DBTP and trait anxiety. In sum, our research suggests the structural features of the PHG and its connectivity with PCC and cuneus may be the neural bases underlying the association between BTP and trait anxiety.