Temporal change in the association between life satisfaction and functional decline with gender differences: an age-specific prospective cohort study.

BACKGROUND: Although life satisfaction (LS) has been shown to predict mortality, research studying the relationship between LS and functional decline is scarce. This study examined the association between LS and functional decline across four time points in young-old Japanese adults. METHODS: We analysed 1,899 community-dwelling 65-year-olds in this age-specific cohort study conducted between 2000 and 2005. The Life Satisfaction Index K was used to evaluate LS and was classified into quartiles. Functional decline was determined using the Japanese Long-Term Care Insurance (LTCI) system: 1) mild disability; 2) severe disability; 3) all-cause mortality; 4) mild or severe disability; 5) severe disability or death; 6) mild or severe disability, or death. Adjusted hazard ratios (HR) with 95% confidence intervals (CI) were calculated using the Cox proportional hazard model. The analyses were conducted in the 8th, 10th, 12th, and 14th years to assess the effect of LS on functional decline across time points. RESULTS: The impact of LS gradually weakened over time. In the 8th year (aged 72-73), a higher LS was associated with a lower risk of mild or severe disability among the women participants (adjusted HR [95% CI] = 0.30 [0.11-0.81]). However, the effect disappeared gradually (adjusted HR [95% CI] = 0.55 [0.27-1.14]) in the 10th year (aged 74-75), 0.72 (0.41-1.26) in the 12th year (aged 76-77), and 0.68 (0.41-1.14) in the 14th year (aged 78-79). This trend continued in severe disability or death (adjusted HR [95% CI] = 0.24 [0.06-0.70], 0.31 [0.11-0.76], 0.57 [0.28-1.14], and 0.60 [0.32-1.12]) and mild or severe disability, or death (adjusted HR [95% CI] = 0.30 [0.14-0.68], 0.46 [0.24-0.87], 0.67 [0.41-1.10], and 0.65 [0.42-1.02]) in the 8th, 10th, 12th, and 14th years, respectively. No statistically significant association was found among men at any time points or in any classification of outcomes. CONCLUSIONS: Higher LS scores in 65-year-old women were associated with a lower risk for functional decline in any combination of mild disability, severe disability, or death. Additionally, the effect of LS was observed to weaken over time. TRIAL REGISTRATION: This is not an intervention survey and does not require registration.

Changes in behavioral activities and transition of depressive symptoms among younger-old community-dwelling adults during 6 years: An age-specific prospective cohort study.

OBJECTIVE: Regular engagement in behavioral activities plays a crucial role against depressive symptoms in older adults. This study aims to explore the relationship between behavioral activities and the temporal evolution of depressive symptoms. METHODS: We included community-dwelling Japanese adults aged 64 or 65 years with and without depressive symptoms enrolled in the New Integrated Suburban Seniority Investigation (NISSIN) project. Depressive symptoms at baseline and follow-up were assessed using the 15-item Geriatric Depression Scale. Behavioral activities were measured by self-reported questions. Risk ratios and 95% confidence intervals were calculated using modified Poisson regression, adjusting for relevant sociodemographic variables and health-related confounders. RESULTS: During the 6 year follow-up period, 139 (10.1%) without depressive symptoms at baseline developed such symptoms over time, while 174 (51.6%) with depressive symptoms improved to the point of these symptoms being absent. The participants without depressive symptoms at baseline and those who engaged in social activity or daily walking at a continued regular frequency (CRF) or an increased frequency (IF) and exercise habits at CRF were the least likely to have depressive symptoms onset at follow-up. There was no significant difference between the changes in behavioral activities and the improvement of depressive symptoms after controlling for confounders. Participants engaging in a greater variety of behavioral activities at CRF were less likely to experience a new onset of depressive symptoms. CONCLUSIONS: Consistent and regular participation in one or more behavioral activities was significantly associated with the onset of depressive symptoms in Japanese community-dwelling older adults.

Prediction of 11-year incidence of psychophysically dependent status or death among community-dwelling younger elderlies: from an age-specified community-based cohort study (the NISSIN project).

BACKGROUND: Predicting adverse health events and implementing preventative measures are a necessary challenge. It is important for healthcare planners and policymakers to allocate the limited resource to high-risk persons. Prediction is also important for older individuals, their family members, and clinicians to prepare mentally and financially. The aim of this study is to develop a prediction model for within 11-year dependent status requiring long-term nursing care or death in older adults for each sex. METHODS: We carried out age-specified cohort study of community dwellers in Nisshin City, Japan. The older adults aged 64 years who underwent medical check-up between 1996 and 2000 were included in the study. The primary outcome was the incidence of the psychophysically dependent status or death or by the end of the year of age 75 years. Univariable logistic regression analyses were performed to assess the associations between candidate predictors and the outcome. Using the variables with p-values less than 0.1, multivariable logistic regression analyses were then performed with backward stepwise elimination to determine the final predictors for the model. RESULTS: Of the 1525 female participants at baseline, 105 had an incidence of the study outcome. The final prediction model consisted of 15 variables, and the c-statistics for predicting the outcome was 0.763 (95% confidence interval [CI] 0.714-0.813). Of the 1548 male participants at baseline, 211 had incidence of the study outcome. The final prediction model consisted of 16 variables, and the c-statistics for predicting the outcome was 0.735 (95% CI 0.699-0.771). CONCLUSIONS: We developed a prediction model for older adults to forecast 11-year incidence of dependent status requiring nursing care or death in each sex. The predictability was fair, but we could not evaluate the external validity of this model. It could be of some help for healthcare planners, policy makers, clinicians, older individuals, and their family members to weigh the priority of support.

Reward-Driven Arousal Impacts Preparation to Perform a Task via Amygdala-Caudate Mechanisms.

Preparing for a challenging task can increase physiological arousal, in particular when potential incentives are large (e.g., a solo musical performance in front of an audience). Here, we examine how potential reward and its influence on arousal, measured by pupil dynamics, are represented in the brain while preparing for a challenging task. We further ask how neural representations during preparation relate to actual performance. Trials resulting in performance failure were characterized by increased pupil dilation as a function of increasing reward magnitude during preparation. Such failure trials were also associated with activation of the right amygdala representing pupil dilation, and the left caudate representing reward magnitude. Notably, increases in functional connectivity between amygdala and caudate preceded performance failure. These findings highlight increased connectivity between neural regions representing reward and arousal in circumstances where reward-driven arousal impairs performance.

Lifestyle and psychosocial factors and a decline in competence in daily living among Japanese early elderly people: from an age-specified community-based cohort study (NISSIN project).

BACKGROUND: To let the early elderly live well, understanding how lifestyle and psychosocial factors related to a decline in competence in daily living is important. METHODS: We investigated the associations between lifestyle and psychosocial factors at age 64 years and a decline in the Tokyo Metropolitan Institute of Gerontology Index of Competence score of ≥ 2 points at age 70 years among the participants in comprehensive medical check-ups living in a city in Japan. Multivariable logistic regression analyses were performed separately for men and women. RESULTS: Of the 1113 eligible men and 1203 eligible women, 110 men and 80 women showed a deteriorated competence in daily living during the 6 years. In men, risk was increased with ≥ 2 nighttime awakenings (multivariable odds ratio [mOR] 2.14, 95% confidence interval [CI] 1.19-3.86) and living alone (mOR 4.68, 95% CI 1.22-18.0), whereas risk was significantly decreased with a medium or fast gait (mOR 0.37 and 0.21, 95% CI 0.21-0.67 and 0.08-0.58) and high academic achievement (mOR 0.32 and 0.43, 95% CI 0.19-0.53 and 0.25-0.72). In women, risk was decreased with high life satisfaction (mOR 0.39, 95% CI 0.16-0.91) and participation in community activities (mOR 0.50, 95% CI 0.29-0.86) but increased with depressive mood (mOR 1.86, 95% CI 1.09-3.18). CONCLUSION: Living alone for men and low life satisfaction for women at age 64 years were markedly associated with the risk of a subsequent declining competence in daily living.

Insular neural system controls decision-making in healthy and methamphetamine-treated rats.

Patients suffering from neuropsychiatric disorders such as substance-related and addictive disorders exhibit altered decision-making patterns, which may be associated with their behavioral abnormalities. However, the neuronal mechanisms underlying such impairments are largely unknown. Using a gambling test, we demonstrated that methamphetamine (METH)-treated rats chose a high-risk/high-reward option more frequently and assigned higher value to high returns than control rats, suggestive of changes in decision-making choice strategy. Immunohistochemical analysis following the gambling test revealed aberrant activation of the insular cortex (INS) and nucleus accumbens in METH-treated animals. Pharmacological studies, together with in vivo microdialysis, showed that the insular neural system played a crucial role in decision-making. Moreover, manipulation of INS activation using designer receptor exclusively activated by designer drug technology resulted in alterations to decision-making. Our findings suggest that the INS is a critical region involved in decision-making and that insular neural dysfunction results in risk-taking behaviors associated with altered decision-making.

A simple computational algorithm of model-based choice preference.

A broadly used computational framework posits that two learning systems operate in parallel during the learning of choice preferences-namely, the model-free and model-based reinforcement-learning systems. In this study, we examined another possibility, through which model-free learning is the basic system and model-based information is its modulator. Accordingly, we proposed several modified versions of a temporal-difference learning model to explain the choice-learning process. Using the two-stage decision task developed by Daw, Gershman, Seymour, Dayan, and Dolan (2011), we compared their original computational model, which assumes a parallel learning process, and our proposed models, which assume a sequential learning process. Choice data from 23 participants showed a better fit with the proposed models. More specifically, the proposed eligibility adjustment model, which assumes that the environmental model can weight the degree of the eligibility trace, can explain choices better under both model-free and model-based controls and has a simpler computational algorithm than the original model. In addition, the forgetting learning model and its variation, which assume changes in the values of unchosen actions, substantially improved the fits to the data. Overall, we show that a hybrid computational model best fits the data. The parameters used in this model succeed in capturing individual tendencies with respect to both model use in learning and exploration behavior. This computational model provides novel insights into learning with interacting model-free and model-based components.

Diabetes Mellitus is Associated With Low Secretion Rates of Immunoglobulin A in Saliva.

BACKGROUND: The association between diabetes mellitus (DM) and low secretory immunoglobulin A (s-IgA) secretion rates is one mechanism suspected of influencing susceptibility to infections among DM patients. However, several studies have shown contradictory results. We examined these two factors to seek evidence of an association among older people. METHODS: We analyzed a prospective cohort of 2306 subjects (1209 men and 1097 women) around 64 years old from the New Integrated Suburban Seniority Investigation (NISSIN) Project in Nisshin, Japan. DM statuses were ascertained from levels of fasting plasma glucose and HbA1c, and s-IgA secretion rates were obtained from 5-min saliva samples. We used an analysis of covariance adjusted for possible confounders to compare s-IgA secretion rates according to DM status. RESULTS: s-IgA secretion rates in DM participants were lower than in those classified as normal (18.6 µg/min vs 15.0 µg/min, P = 0.03), even after elimination of the effects of possible confounders. CONCLUSIONS: DM was associated with lower s-IgA secretion rates. This suggests that lower s-IgA levels may be a mechanism of susceptibility to infection in individuals with DM.

[Interoception and decision-making].

We sometimes make decisions relying not necessarily on deliberative thoughts but on intuitive and emotional processes in uncertain situations. The somatic marker hypothesis proposed by Damasio argued that interoception, which means bodily responses such as sympathetic activity, can be represented in the insula and anterior cingulate cortex and can play critical roles in decision-making. Though this hypothesis has been criticized in its theoretical and empirical aspects, recent studies are expanding the hypothesis to elucidate multiple bodily responses including autonomic, endocrine, and immune activities that affect decision-making. In addition, cumulative findings suggest that the anterior insula where the inner model of interoception is represented can act as an interface between the brain and body in decision-making. This article aims to survey recent findings on the brain-body interplays underlying decision-making, and to propose hypotheses on the significance of the body in decision-making.

The influence of cardiac synchronisation on self-attribution to external objects in male participants.

Interoception, the representation of our bodily state derived from physiological signals, is fundamental to our sense of self. Previous studies using cardiac feedback paradigms demonstrated interoceptive effects on self-perception. However, it remains unclear whether interoceptive information can extend self-attribution to non-bodily objects. This study aimed to elucidate whether cardiac signals can induce self-attribution to non-bodily objects and how interoceptive accuracy modulates this effect. A total of 44 male volunteers participated in an emotion assignment task where they viewed images of palms (bodily targets) and spheres (non-bodily targets) flashing in or out of sync with their heartbeat and assigned emotional images (positive/negative) to these targets. A heartbeat discrimination task was used to measure the interoceptive accuracy. The results showed no significant effect of synchronisation on emotion assignment for either the target type or the valence of the emotional images. However, participants with high interoceptive accuracy attributed both positive and negative images more to synchronised targets than those with low interoceptive accuracy. These findings suggest that although cardiac synchronisation may not uniformly facilitate the self-attribution of external objects, interoceptive accuracy may mediate attention to synchrony. Future studies should explore the conditions under which cardiac signals influence self-attribution.

Association of brain-autonomic activities and task accuracy under cognitive load: a pilot study using electroencephalogram, autonomic activity measurements, and arousal level estimated by machine learning.

The total amount of mental activity applied to working memory at a given point in time is called cognitive load, which is an important factor in various activities in daily life. We have proposed new feature quantities that reflect the time-series changes in the power of typical frequency bands in electroencephalogram (EEG) for use in examining the relationship between brain activity and behavior under cognitive load. We also measured heart rate variability (HRV) and spontaneous skin conductance responses (SCR) to examine functional associations among brain activity, autonomic activity, and behavior under cognitive load. Additionally, we applied our machine learning model previously developed using EEG to the estimation of arousal level to interpret the brain-autonomic-behavior functional association under cognitive load. Experimental data from 12 healthy undergraduate students showed that participants with higher levels of infra-slow fluctuations of alpha power have more cognitive resources and thus can process information under cognitive load more efficiently. In addition, HRV reflecting parasympathetic activity correlated with task accuracy. The arousal level estimated using our machine learning model showed its robust relationship with EEG. Despite the limitation of the sample size, the results of this pilot study suggest that the information processing efficiency of the brain under cognitive load is reflected by time-series fluctuations in EEG, which are associated with an individual's task performance. These findings can contribute to the evaluation of the internal state of humans associated with cognitive load and the prediction of human behaviors in various situations under cognitive load.

Striatal GABA levels correlate with risk sensitivity in monetary loss.

Background: Decision-making under risk is a common challenge. It is known that risk-taking behavior varies between contexts of reward and punishment, yet the mechanisms underlying this asymmetry in risk sensitivity remain unclear. Methods: This study used a monetary task to investigate neurochemical mechanisms and brain dynamics underpinning risk sensitivity. Twenty-eight participants engaged in a task requiring selection of visual stimuli to maximize monetary gains and minimize monetary losses. We modeled participant trial-and-error processes using reinforcement learning. Results: Participants with higher subjective utility parameters showed risk preference in the gain domain (r = -0.59) and risk avoidance in the loss domain (r = -0.77). Magnetic resonance spectroscopy (MRS) revealed that risk avoidance in the loss domain was associated with γ-aminobutyric acid (GABA) levels in the ventral striatum (r = -0.42), but not in the insula (r = -0.15). Using functional magnetic resonance imaging (fMRI), we tested whether risk-sensitive brain dynamics contribute to participant risky choices. Energy landscape analyses demonstrated that higher switching rates between brain states, including the striatum and insula, were correlated with risk avoidance in the loss domain (r = -0.59), a relationship not observed in the gain domain (r = -0.02). Conclusions: These findings from MRS and fMRI suggest that distinct mechanisms are involved in gain/loss decision making, mediated by subcortical neurometabolite levels and brain dynamic transitions.

Dual decline in subjective gait speed and domain-specific cognition is associated with higher risk of incident dementia in older Japanese adults: A 15-year age-specific cohort study.

OBJECTIVES: Dual decline in gait speed and cognition has been found to have higher dementia risk than no decline or pure decline. However, evidence from the Asian population is lacking. Therefore, we aimed to investigate the association of dual decline from age 65 to 70 years with late-life dementia in older Japanese adults with different personal characteristics. METHODS: Data were collected from an age-specific cohort study conducted in 482 Japanese 65-year-old adults. We investigated participant demographics, medical histories, lifestyles, subjective gait speed, and cognition at both 64/65 and 70/71 years old, and confirmed dementia until age of 85 years. Cox proportion hazard models were used to estimate the risk of dementia, with adjustments for covariates, and death was treated as a competing risk. RESULTS: After a mean follow-up period of 12.5-years, 111 participants developed dementia. Older adults with dual decline are more likely to have hyperlipidemia, diabetes, and smoking habits. And we found that dual decline in gait speed and domain-specific cognition was associated with a higher risk of dementia compared with no decline in most cognitive tests, with the highest risk observed for gait speed combined with memory (sub-distribution hazard ratio:3.89, 95 %, confidence intervals: [1.68-9.01]). However, significant differences only existed in men after stratification by sex. CONCLUSIONS: A dual decline in subjective gait speed and cognition may serve as a robust predictor of dementia over a decade prior to its onset, particularly in men. These findings highlighted the importance of screening for dual decline at an early age.

Unintentional temporal context-based prediction of emotional faces: an electrophysiological study.

The ability to extract sequential regularities embedded in the temporal context or temporal structure of sensory events and to predict upcoming events based on the extracted sequential regularities plays a central role in human cognition. In the present study, we demonstrate that, without any intention, upcoming emotional faces can be predicted based on sequential regularities, by showing that prediction error responses as reflected by visual mismatch negativity (MMN), an event-related brain potential (ERP) component, were evoked in response to emotional faces that violated a regular alternation pattern of 2 emotional faces (fearful and happy faces) under a situation where the emotional faces themselves were unrelated to the participant's task. Face-inversion and negative-bias effects in the visual MMN further indicated the involvement of holistic face representations. In addition, through successive source analyses of the visual MMN, it was revealed that the prediction error responses were composed of activations mainly in the face-responsible visual extrastriate areas and the prefrontal areas. The present results provide primary evidence for the existence of the unintentional temporal context-based prediction of biologically relevant visual stimuli as well as empirical support for the major engagement of the visual and prefrontal areas in unintentional temporal context-based prediction in vision.

Pro-inflammatory cytokine predicts reduced rejection of unfair financial offers.

OBJECTIVES: This study aimed to examine one of biological correlates, pro-inflammatory cytokine, in rejection of unfair financial offers in the Ultimatum Game (UG), where the division of a sum of money is proposed and the player can accept or reject this offer. METHODS: Nineteen participants played 20 trials of the UG as responders, and they were proposed unfair offers in a half of the trials. Baseline levels of several pro-inflammatory and anti-inflammatory cytokines, subjective happiness, and depression of them were measured. RESULTS: Participants with higher levels of the pro-inflammatory cytokine, interleukin (IL)-6 rejected fewer unfair offers. This effect of IL-6 levels on decision-making was independent from other pro-inflammatory cytokines, anti-inflammatory cytokines, subjective happiness, and depression. CONCLUSIONS: These results suggested that chronic higher levels of IL-6 might affect functions of neural regions related to decision making, and thus can modulate rejection of unfair offers.

[Integration of Interoception, Decision-Making, and Affect: Allostasis as Predictive Processing].

Allostasis refers to the mechanism by which the brain changes bodily states to adapt to the environment in order to achieve stability or homeostasis. This concept was originally proposed by Sterling and Eyer in 1988. Recently, allostasis has been reconceptualized from the viewpoint of predictive processing, a theory arguing that the brain regulates perception and motor movement by generating predictions through inner models of the external world and self and minimizing the prediction error between the predictions and sensory signals. This idea provides integrated explanations of a wide range of phenomena, including homeostasis, decision-making, and the accompanying emotions and consciousness. Although this theory is a hypothesis, empirical evidence has been proposed in recent years. This article introduces the theory of predictive processing of allostasis, recent related research findings, and issues to be examined in the future.

The physiological basis of leader-follower roles in the dyadic alternating tapping task.

Introduction: Cooperative and collaborative behaviors are important concepts for co-creative communication. One of the key elements for these behaviors is the leader-follower roles in human communication. Leaders are those who maintain their own pace and rhythm, on the contrary, followers are those who follow the pace and rhythm of the other. Well-coordinated leader-follower roles would produce better cooperative and collaborative behaviors, which could promote co-creative communication. Methods: Here, to explore the physiological basis for the leader-follower roles, we conducted the dyadic alternating tapping task with electrocardiographic and electroencephalographic recordings. The task would be stable for modeling human communication in the laboratory because it includes timing control in tens of milliseconds and turn-taking. Given that human communications are complex and constantly fluctuating, this study estimated the degree of leader-follower with the state-space model. This model allowed us to calculate two parameters independently for estimating the degree of leader-follower of each participant: αSelf (degree of one's tap(n) was explained by one's tap(n-1)) and αPair (degree of one's tap(n) was explained by one's tap (n-1) and pair's tap (n-1)). Results: The result showed heart rate synchronization in the group in which both participants had high αPair. Also, the high-frequency component of heart rate variability was positively correlated with αPair. EEG analyses suggested the deactivation of the mirror neuron system (increasing φ1) in the participants with higher αSelf than lower ones. The activation of the mirror neuron system (increasing φ2) was shown in the participants with lower αPair than higher ones. Discussion: These data of physiological basis for leader-follower roles could be useful for the constructivist approach to co-creative communication.

Effects of mild psychological stress on facial impressions.

Introduction: Appearance plays an important role in maintaining a positive impression in social interactions. Psychological stress is known to have an adverse effect on facial skin, as indicated in previous studies. However, no study has investigated the negative effect of stress on facial impressions. Therefore, we aimed to investigate changes in impressions from facial images before and after mental stress tasks using an online survey. Method: Thirteen Japanese men were recruited to have their facial photographs taken before and after undergoing a psychological stress task. We observed the physiological effects of an increased heart rate and decreased blood flow on the cheek skin. Four average facial images were created for each time point (control: "baseline;" stress: "0H," "1H," and "3H") from their facial photographs. An online survey was conducted with 700 Japanese participants, who compared the "baseline" to other images and selected one of two options in each of the six questionnaire items of impressions. Results: The results showed that the rate of participants who chose "baseline" was significantly lower in the items "looks tired," "looks old," and "looks irritated" and higher in "looks clean-cut" and "looks healthy" compared to other images created from photographs after the stress task ("0H," "1H," and "3H"). Conclusion: These results suggest that psychological stress loading not only causes physiological changes in autonomic nervous activity and skin blood flow but also negatively impacts facial impressions for a few hours following a mild stress load.

Changes in social activities and the occurrence and persistence of depressive symptoms: Do type and combination of social activities make a difference?

OBJECTIVE: We aimed to explore the association between changes in social activities and the occurrence/persistence of depressive symptoms and investigate the difference in effect sizes among the types and combinations of social activities. METHODS: The study adopted a valid 15-item Geriatric Depression Scale to assess depressive symptoms in 2480 community-dwelling adults aged 64/65 years. Changes in social-related, learning, and personal activities were classified into four categories: continued low frequency (CLF), increased frequency (IF), decreased frequency (DF), and continued regular frequency (CRF)1. Relative ratios (RRs) and 95% confidence intervals (95% CI) were calculated using a modified Poisson regression model. RESULTS: Those without depressive symptoms at baseline and who engaged in social-related (RRIF = 0.56 (0.39, 0.81), RRCRF = 0.55 (0.41, 0.74)), learning (RRIF = 0.63 (0.44, 0.89), RRCRF = 0.62 (0.46, 0.85)), and personal activities (RRIF = 0.37 (0.24, 0.57), RRCRF = 0.41 (0.30, 0.56)) at IF or CRF were less likely to develop depressive symptoms. Those with depressive symptoms at baseline, engaging in personal activities at IF (RR=0.67 (0.51, 0.87)) and CRF (RR= 0.80 (0.65-1.00)) were less likely to have persistent depressive symptoms. Participation in all three activities consistently at a regular frequency was inversely associated with the occurrence/persistence of depressive symptoms. CONCLUSIONS: The effect of personal activities was more manifest in preventing depressive symptoms than the other two kinds, regardless of depressive symptoms at baseline. Regularly engaging in a combination of all three activities at baseline and follow-up was associated with the occurrence and persistence of depressive symptoms.