Neural intrinsic connectivity networks associated with risk aversion in old age

Connectome-based prediction of decreased trust propensity in older adults with mild cognitive impairment: A resting-state functional magnetic resonance imaging study

Trust propensity (TP) relies more on social than economic rationality to transform the perceived probability of betrayal into positive reciprocity expectations in older adults with normal cognition. While deficits in social rationality have been observed in older adults with mild cognitive impairment (MCI), there is limited research on TP and its associated resting-state functional connectivity (RSFC) mechanisms in this population. To measure TP and related psychological functions (affect, motivation, executive cognition, and social cognition), MCI (n = 42) and normal healthy control (NHC, n = 115) groups completed a one-shot trust game and additional assessments of related psychological functions. RSFC associated with TP was analyzed using connectome-based predictive modeling (CPM) and lesion simulations. Our behavioral results showed that the MCI group trusted less (i.e., had lower TP) than the NHC group, with lower TP associated with higher sensitivity to the probability of betrayal in the MCI group. In the MCI group, only negative CPM models (RSFC negatively correlated with TP) significantly predicted TP, with a high salience network (SN) contribution. In contrast, in the NHC group, positive CPM models (RSFC positively correlated with TP) significantly predicted TP, with a high contribution from the default mode network (DMN). In addition, the total network strength of the NHC-specific positive network was lower in the MCI group than in the NHC group. Our findings demonstrated a decrease in TP in the MCI group compared to the NHC group, which is associated with deficits in social rationality (social cognition, associated with DMN) and increased sensitivity to betrayal (affect, associated with SN) in a trust dilemma. In conclusion, our study contributes to understanding MCI-related alterations in trust and their underlying neural mechanisms.

Change in Decision-Making Analysis and Preferences in Old Age

OBJECTIVES

To test the hypotheses that decision making ability declines in old age and that a higher level of cognitive reserve is associated with a reduced rate of decline.

METHODS

As part of an ongoing cohort study, 982 older adults without dementia at study enrollment completed measures of purpose in life and cognitive activity which were used as markers of cognitive reserve. At annual intervals thereafter, they completed 6 tests of decision making.

RESULTS

In a factor analysis of baseline decision making scores, 3 measures (financial/health literacy, financial/health decision making, scam susceptibility) loaded on an "analytic" factor and 3 (temporal discounting small stakes, temporal discounting large stakes, risk aversion) loaded on a "preferences" (for temporal discounting and avoiding risk) factor. During a mean of 4.7 years of follow-up (standard deviation = 2.9), analytic factor scores decreased (mean = 0.042-unit per year, standard error [SE] = 0.006, p < .001) and preferences factor scores increased (mean = 0.021-unit per year, SE = 0.006, p < .001), with a correlation of 0.13 (p < .001) between rates of change. Evidence of an association between cognitive reserve and decision making was mixed with purpose in life related to change in analytic decision making, whereas past (but not current) cognitive activity was related to change in decision making preferences.

DISCUSSION

Decision making analysis and preferences change over time in late life. Change over time in decision making components is relatively independent and differentially related to age and cognitive reserve.

A Molecular Basis of Human Brain Connectivity

Neuroimaging is commonly used to infer human brain connectivity, but those measurements are far-removed from the molecular underpinnings at synapses. To uncover the molecular basis of human brain connectivity, we analyzed a unique cohort of 98 individuals who provided neuroimaging and genetic data contemporaneous with dendritic spine morphometric, proteomic, and gene expression data from the superior frontal and inferior temporal gyri. Through cellular contextualization of the molecular data with dendritic spine morphology, we identified hundreds of proteins related to synapses, energy metabolism, and RNA processing that explain between-individual differences in functional connectivity and structural covariation. By integrating data at the genetic, molecular, subcellular, and tissue levels, we bridged the divergent fields of molecular biology and neuroimaging to identify a molecular basis of brain connectivity.

One-Sentence Summary

Dendritic spine morphometry and synaptic proteins unite the divergent fields of molecular biology and neuroimaging.

Edge-centric functional network predicts risk propensity in economic decision-making: evidence from a resting-state fMRI study

Despite node-centric studies revealing an association between resting-state functional connectivity and individual risk propensity, the prediction of future risk decisions remains undetermined. Herein, we applied a recently emerging edge-centric method, the edge community similarity network (ECSN), to alternatively describe the community structure of resting-state brain activity and to probe its contribution to predicting risk propensity during gambling. Results demonstrated that inter-individual variability of risk decisions correlates with the inter-subnetwork couplings spanning the visual network (VN) and default mode network (DMN), cingulo-opercular task control network, and sensory/somatomotor hand network (SSHN). Particularly, participants who have higher community similarity of these subnetworks during the resting state tend to choose riskier and higher yielding bets. And in contrast to low-risk propensity participants, those who behave high-risky show stronger couplings spanning the VN and SSHN/DMN. Eventually, based on the resting-state ECSN properties, the risk rate during the gambling task is effectively predicted by the multivariable linear regression model at the individual level. These findings provide new insights into the neural substrates of the inter-individual variability in risk propensity and new neuroimaging metrics to predict individual risk decisions in advance.

Subjective socioeconomic status is associated with risk aversion in a community-based cohort of older adults without dementia

Attitudes towards risk impact financial decisions that are critical in older adulthood. Socioeconomic status (SES) influences an individual’s level of risk aversion; however, the association of subjective SES (i.e., social standing relative to others) with risk aversion has not been explored. We examined whether subjective SES is associated with risk aversion independent of objective SES (i.e., income, education). Participants were 933 older adults without dementia from the Rush Memory and Aging Project (MAP) or Minority Aging Research Study (MARS), two longitudinal epidemiologic studies of aging. Participants completed assessments of risk aversion, subjective SES, and cognition. We examined associations of subjective SES with risk aversion using mixed models adjusting for participant characteristics, objective markers of SES and global cognition. In bivariate analyses, lower global cognitive functioning, lower income, female sex, Black race, and lower subjective SES were associated with greater risk aversion. Results of the nonlinear mixed effects model revealed that higher subjective SES was associated with less risk aversion (Estimate = −0.238, SE = 0.083, p = 0.004), after controlling for covariates. Age, sex, race, and global cognition were also associated with risk aversion in the mixed effects model (ps ≤0.03), although income and education were not (ps ≥ 0.27) The relationship between subjective SES and risk aversion did not differ by sex or race (ps ≥ 0.31). Findings suggest that subjective SES contributes to risk aversion regardless of sex or race. Findings support the importance of considering subjective indicators of SES as they may impact an older adult’s economic preferences.

Cognitive and neuroimaging correlates of financial exploitation vulnerability in older adults without dementia: Implications for early detection of Alzheimer's disease

Neuropathology characteristic of Alzheimer's disease (AD) begins to accumulate years to decades before cognitive changes are clinically detectable on standard neuropsychological tests. This presents a challenge for early intervention efforts and has spurred research on the identification of behavioral correlates of early neuropathological changes. Recent evidence suggests that financial exploitation vulnerability (FEV) due to impaired decision making may serve as an early behavioral manifestation of AD neuropathology, thereby indicating an increased likelihood for subsequent cognitive decline. An understanding of the underlying mechanisms of FEV is therefore warranted for the identification of individuals at risk for cognitive decline due to AD, and for empowering and protecting older adults vulnerable to financial exploitation. In the current review, we first highlight the devastating consequences of financial exploitation of older adults. We then summarize research on the cognitive, neuroimaging, and neuropathological correlates of FEV in older adults without dementia and propose a theoretical model in which early accumulation of AD pathology manifests as FEV. We conclude with clinical implications and directions for future research.

Susceptibility to Scams in Older Black and White Adults

Previous reports on racial differences in scam susceptibility have yielded mixed findings, and few studies have examined reasons for any observed race differences. Older Black and White participants without dementia (N = 592) from the Minority Aging Research Study and the Rush Memory and Aging Project who completed a susceptibility to scam questionnaire and other measures were matched according to age, education, sex, and global cognition using Mahalanobis distance. In adjusted models, older Black adults were less susceptible to scams than older White adults (Beta = -0.2496, SE = 0.0649, p = 0.0001). Contextual factors did not mediate and affective factors did not moderate this association. Analyses of specific items revealed Black adults had greater knowledge of scam targeting of older adults and were less likely to pick up the phone for unidentified callers. Older Black adults are less susceptible to scams than demographically-matched older White adults, although the reasons remain unknown.

Functional Connectivity Correlates of Perceived Financial Exploitation in Older Adults

Financial exploitation (FE) in old age is devastating and common; however, the neural correlates of FE are poorly understood. Previous studies of FE in older adults have implicated declines in decision making and social cognition as two risk factors for FE in later life. Here we examined whether functional connectivity among brain regions implicated in decision making and social cognition differed for those with an experience of FE vs. those without. Participants included 16 older adults without cognitive impairment who reported FE (Mean age = 70.5, 62.5% female, Mean education = 16.0 years) and 16 demographically and cognitively matched adults who denied a history of FE (Mean age = 65.1, 37.5% female, Mean education = 15.1 years). Measures of whole-brain resting-state functional connectivity in the hippocampus, insula, and medial frontal cortex were derived for each group. Compared to the non-FE group, FE was associated with greater functional connectivity between the right hippocampus and bilateral temporal regions, and less functional connectivity between the right hippocampus and the right cerebellum and bilateral lingual gyri. The FE group showed less connectivity between the right and left insula and cingulate cortex, and between the right insula and regions of the left lateral temporal gyrus and dorsolateral prefrontal cortex. Finally, the FE group showed greater functional connectivity between the medial frontal cortex and the right lateral temporal gyrus and orbitofrontal cortex, and less functional connectivity with the right pre- and postcentral gyri. Results suggest that perceived FE in old age is associated with whole-brain functional connectivity differences involving the hippocampus, insula, and medial frontal cortex, consistent with models implicating age-associated changes in decision making and social cognition in FE.

Risk Aversion and Alzheimer Disease in Old Age

OBJECTIVE

To test the hypothesis that late-life risk aversion is partly a prodromal sign of dementia.

METHODS

The authors' design was a longitudinal clinical-pathologic cohort study. The setting included participants' residences in the Chicago area, and a total of 874 older persons without dementia were enrolled. At baseline, risk aversion was assessed with questions involving choices between certain smaller rewards and uncertain larger rewards. At annual intervals thereafter, participants underwent evaluations that included cognitive testing and diagnosis of mild cognitive impairment (MCI) and dementia. At death, a neuropathologic examination was done to quantify common pathologies linked to dementia.

RESULTS

Risk aversion at study onset ranged from 0.05-0.91 (mean: 0.32, standard deviation: 0.31). During a mean of 4.6 years of follow-up, 123 (of 874) developed dementia. Higher risk aversion was associated with higher dementia incidence (hazard ratio [HR]: 2.08; 95% confidence interval: 1.18, 3.65) and more rapid decline in episodic (estimate: -0.062; standard error [SE]: 0.019; t [3677]: -3.33; p < 0.001) and semantic (estimate: -0.039; SE: 0.015; t [3655]: -2.61; p = 0.009) memory but not in other cognitive systems. Of 702 people without cognitive impairment at baseline, 223 developed incident MCI. Higher risk aversion was associated with higher incidence of MCI (HR: 2.10; 95% confidence interval: 1.34, 3.29) and more rapid episodic memory decline. In 181 neuropathologically examined individuals, higher risk aversion was associated with higher levels of plaques, tangles, and cerebral amyloid angiopathy.

CONCLUSION

The results support the hypothesis that high risk aversion in old age is partly an early sign of the pathology of Alzheimer disease.

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.

Religious Orders Study and Rush Memory and Aging Project

BACKGROUND

The Religious Orders Study and Rush Memory and Aging Project are both ongoing longitudinal clinical-pathologic cohort studies of aging and Alzheimer's disease (AD).

OBJECTIVES

To summarize progress over the past five years and its implications for understanding neurodegenerative diseases.

METHODS

Participants in both studies are older adults who enroll without dementia and agree to detailed longitudinal clinical evaluations and organ donation. The last review summarized findings through the end of 2011. Here we summarize progress and study findings over the past five years and discuss new directions for how these studies can inform on aging and AD in the future.

RESULTS

We summarize 1) findings on the relation of neurobiology to clinical AD; 2) neurobiologic pathways linking risk factors to clinical AD; 3) non-cognitive AD phenotypes including motor function and decision making; 4) the development of a novel drug discovery platform.

CONCLUSION

Complexity at multiple levels needs to be understood and overcome to develop effective treatments and preventions for cognitive decline and AD dementia.

How Does Psychosocial Behavior Contribute to Cognitive Health in Old Age?

With the aging of the U.S. population, the number of cognitively disabled persons is expected to substantially increase in coming decades, underscoring the urgent need for effective interventions. Here, we review the current evidence linking psychosocial factors to late-life cognitive loss and consider the study design needed to illuminate the biologic bases of the associations. We then examine an ongoing study that includes several of the key design elements, the Rush Memory and Aging Project. In this longitudinal clinical-pathological cohort study, indicators of personality, social connectedness, and psychological well-being were shown to predict late-life cognitive outcomes. Participants who died underwent a uniform neuropathologic examination to quantify common dementia-related pathologies. Some psychosocial indicators were associated with cerebral infarction; some indicators modified the association of neurodegenerative pathologies with cognitive loss; and the association of some indicators with cognitive outcomes appears to be independent of the pathologies traditionally associated with late-life dementia. These findings suggest that psychosocial behavior influences late-life cognitive health through multiple neurobiologic mechanisms. A better understanding of these mechanisms may lead to novel strategies for preserving cognitive health in old age.

Cognitive decline is associated with risk aversion and temporal discounting in older adults without dementia

Risk aversion and temporal discounting are preferences that are strongly linked to sub-optimal financial and health decision making ability. Prior studies have shown they differ by age and cognitive ability, but it remains unclear whether differences are due to age-related cognitive decline or lower cognitive abilities over the life span. We tested the hypothesis that cognitive decline is associated with higher risk aversion and temporal discounting in 455 older persons without dementia from the Memory and Aging Project, a longitudinal cohort study of aging in Chicago. All underwent repeated annual cognitive evaluations using a detailed battery including 19 tests. Risk aversion was measured using standard behavioral economics questions: participants were asked to choose between a certain monetary payment versus a gamble in which they could gain more or nothing; potential gamble gains varied across questions. Temporal discounting: participants were asked to choose between an immediate, smaller payment and a delayed, larger one; two sets of questions addressed small and large stakes based on payment amount. Regression analyses were used to examine whether prior rate of cognitive decline predicted level of risk aversion and temporal discounting, controlling for age, sex, and education. Over an average of 5.5 (SD=2.9) years, cognition declined at an average of 0.016 units per year (SD=0.03). More rapid cognitive decline predicted higher levels of risk aversion (p=0.002) and temporal discounting (small stakes: p=0.01, high stakes: p=0.006). Further, associations between cognitive decline and risk aversion (p=0.015) and large stakes temporal discounting (p=0.026) persisted in analyses restricted to persons without any cognitive impairment (i.e., no dementia or mild cognitive impairment); the association of cognitive decline and small stakes temporal discounting was no longer statistically significant (p=0.078). These findings are consistent with the hypothesis that subtle age-related changes in cognition can detrimentally affect individual preferences that are critical for maintaining health and well being.

The neural correlates of risk propensity in males and females using resting-state fMRI

Men are more risk prone than women, but the underlying basis remains unclear. To investigate this question, we developed a trait-like measure of risk propensity which we correlated with resting-state functional connectivity to identify sex differences. Specifically, we used short- and long-range functional connectivity densities to identify associated brain regions and examined their functional connectivities in resting-state functional magnetic resonance imaging (fMRI) data collected from a large sample of healthy young volunteers. We found that men had a higher level of general risk propensity (GRP) than women. At the neural level, although they shared a common neural correlate of GRP in a network centered at the right inferior frontal gyrus, men and women differed in a network centered at the right secondary somatosensory cortex, which included the bilateral dorsal anterior/middle insular cortices and the dorsal anterior cingulate cortex. In addition, men and women differed in a local network centered at the left inferior orbitofrontal cortex. Most of the regions identified by this resting-state fMRI study have been previously implicated in risk processing when people make risky decisions. This study provides a new perspective on the brain-behavioral relationships in risky decision making and contributes to our understanding of sex differences in risk propensity.

The dissociation between early and late selection in older adults

Older adults exhibit a reduced ability to ignore task-irrelevant stimuli; however, it remains to be determined where along the information processing stream the most salient age-associated changes occur. In the current study, ERPs provided an opportunity to determine whether age-related differences in processing task-irrelevant stimuli were uniform across information processing stages or disproportionately affected either early or late selection. ERPs were measured in young and old adults during a color-selective attention task in which participants responded to target letters in a specified color (attend condition) while ignoring letters in a different color (ignore condition). Old participants were matched to two groups of young participants on the basis of neuropsychological test performance: one using age-appropriate norms and the other using test scores not adjusted for age. There were no age-associated differences in the magnitude of early selection (attend-ignore), as indexed by the size of the anterior selection positivity and posterior selection negativity. During late selection, as indexed by P3b amplitude, both groups of young participants generated neural responses to target letters under the attend versus ignore conditions that were highly differentiated. In striking contrast, old participants generated a P3b to target letters with no reliable differences between conditions. Individuals who were slow to initiate early selection appeared to be less successful at executing late selection. Despite relative preservation of the operations of early selection, processing delays may lead older participants to allocate excessive resources to task-irrelevant stimuli during late selection.

Overview and findings from the rush Memory and Aging Project

The Memory and Aging Project is a longitudinal, epidemiologic clinical-pathologic cohort study of common chronic conditions of aging with an emphasis on decline in cognitive and motor function and risk of Alzheimer's disease (AD). In this manuscript, we first summarize the study design and methods. Then, we present data on: (1) the relation of motor function to cognition, disability, and death; (2) the relation of risk factors to cognitive and motor outcomes, disability and death; (3) the relation of neuropathologic indices to cognitive outcomes; (4) the relation of risk factors to neuropathologic indices; and (5) additional study findings. The findings are discussed and contextualized.

Risk Aversion is Associated with Decision Making among Community-Based Older Persons

Background: Risk aversion is associated with many important decisions among younger and middle aged persons, but the association of risk aversion with decision making has not been well studied among older persons who face some of the most significant decisions of their lives. Method: Using data from 606 community-dwelling older persons without dementia from the Rush Memory and Aging Project, an ongoing longitudinal epidemiologic study of aging, we examined the association of risk aversion with decision making. Risk aversion was measured using standard behavioral economics questions in which participants were asked to choose between a certain monetary payment ($15) versus a gamble in which they could gain more than $15 or gain nothing; potential gamble gains ranged from $20 to $300 with the gain amounts varied randomly over questions. Decision making was measured using a 12 item version of the Decision Making Competence Assessment Tool. Findings: In a linear regression model adjusted for age, sex, education, and income, greater risk aversion was associated with poorer decision making [estimate = −1.03, standard error (SE) = 0.35, p = 0.003]. Subsequent analyses showed that the association of risk aversion with decision making persisted after adjustment for global cognitive function as well as executive and non-executive cognitive abilities. Conclusion: Similar to findings from studies of younger persons, risk aversion is associated with poorer decision making among older persons who face a myriad of complex and influential decisions.