Exploring the efficacy of sense of Okayness (SOK) as an antidote for stress in older adults: the role of SOK elevation intervention, heart rate variability (HRV), and cognitive performance in stressful and relaxing situations.

Sense of Okayness (SOK) is an emerging concept that describes a person's ability to remain stable and unshaken in the face of life transitions and hardships. This quality enables effective stress regulation and heightened tolerance to uncertainty. To investigate the possible role of the parasympathetic nervous system (PNS) in mediating the relationship between SOK and stress regulation among older individuals, an analytical sample of N = 69 participants (74% women) with a mean age of 78.75 years (SD age = 6.78) was recruited for a standardized cognitive assessment and stress induction. Baseline heart rate variability (HRV), measured via electrocardiogram (ECG), and SOK assessments were conducted prior to stress induction, along with a baseline cognitive evaluation. Subsequently, participants were subjected to a psychosocial stress paradigm, followed by either a 30-minute SOK elevation intervention (n = 40) or a control condition with nature sounds (n = 29). A second cognitive assessment was administered post-intervention, with continuous HRV measurement through ECG. The results revealed significant HRV changes due to the experimental intervention, though no significant differences were observed between the SOK intervention and control groups. Interestingly, individuals with high trait SOK displayed more stable HRV trajectories, exhibiting a smaller decline during the stress intervention and a milder increase during both the stressor and SOK intervention phases. Overall, these findings do suggest a significant association between SOK, parasympathetic activity, and stress reactivity. These results prompt further investigation into whether personality patterns, such as a strong SOK, may be linked to reduced vagal reactivity and better coping in old age.

The effects of left dorsolateral prefrontal transcranial direct current stimulation on episodic future thinking following acute psychosocial stress.

INTRODUCTION: Research on stress-related disorders and brain imaging suggests that (acute) stress might impact the capacity to mentally simulate specific episodic future events (EFT) through the effects of cortisol on brain regions supporting this cognitive function, such as the prefrontal cortices. This study aims to examine the mechanisms underlying this link, using transcranial Direct Current Stimulation (tDCS) over the left dorsolateral prefrontal cortex. METHODS: 60 healthy participants were subjected to the Montreal Imaging Stress Task (MIST), followed by either active or sham tDCS. After stimulation, the EFT task was administered. Salivary cortisol was measured throughout the protocol. RESULTS: Higher cortisol AUCi values were linked to less specific episodic future thoughts. Moreover, active tDCS enhanced EFT specificity irrespective of cortisol, especially in high trait ruminators. We did not observe an effect from active tDCS on cortisol AUCi, and equally there was no interaction effect between cortisol AUCi and stimulation condition predictive for EFT specificity. CONCLUSION: Although we did not find evidence for the effects of tDCS on the HPA-system, our data reveal a crucial link between two critical predictors of mental health for the first time, and provide a solution to help rehabilitate EFT deficits.Trial registration: Netherlands National Trial Register identifier: ntr004..

The social transmission of stress in animal collectives.

The stress systems are powerful mediators between the organism's systemic dynamic equilibrium and changes in its environment beyond the level of anticipated fluctuations. Over- or under-activation of the stress systems' responses can impact an animal's health, survival and reproductive success. While physiological stress responses and their influence on behaviour and performance are well understood at the individual level, it remains largely unknown whether-and how-stressed individuals can affect the stress systems of other group members, and consequently their collective behaviour. Stressed individuals could directly signal the presence of a stressor (e.g. via an alarm call or pheromones), or an acute or chronic activation of the stress systems could be perceived by others (as an indirect cue) and spread via social contagion. Such social transmission of stress responses could then amplify the effects of stressors by impacting social interactions, social dynamics and the collective performance of groups. As the neuroendocrine pathways of the stress response are highly conserved among vertebrates, transmission of physiological stress states could be more widespread among non-human animals than previously thought. We therefore suggest that identifying the extent to which stress transmission modulates animal collectives represents an important research avenue.

Determinants and Mechanisms of the Renin-Aldosterone Stress Response.

OBJECTIVE: The renin-angiotensin-aldosterone system (RAAS) plays a relevant role in regulating blood pressure and thus maintaining cardiovascular homeostasis. Although it was recently shown that RAAS parameters are responsive to acute psychosocial stress, the psychobiological determinants of the acute stress-induced RAAS activation have not yet been investigated. In a randomized placebo-controlled design, we investigated potential psychological and physiological determinants of the RAAS response and underlying mechanisms. METHODS: Fifty-seven young healthy male participants underwent either an acute standardized psychosocial stress test or a nonstress placebo task. We measured aldosterone in plasma and saliva, as well as renin, and the stress-reactive endocrine measures adrenocorticotropic hormone (ACTH), epinephrine, and norepinephrine in plasma at rest, immediately after the task and several times up to 3 hours thereafter. Moreover, we assessed stress-reactive psychological (anticipatory cognitive stress appraisal, mood, physical discomfort) and basal demographic-physiological measures (age, body mass index, blood pressure). RESULTS: Acute psychosocial stress elicited changes in all assessed endocrine (p values ≤ .028, ηp2 values ≥ 0.07) and stress-reactive psychological measures (p values ≤ .003, ηp2 values ≥ 0.15). The basal parameter body mass index, the stress-reactive endocrine parameters ACTH and norepinephrine, and the psychological parameter anticipatory stress appraisal were identified as determinants of higher RAAS parameter reactivity to acute psychosocial stress. The association between anticipatory cognitive stress appraisal and plasma RAAS measures was fully mediated by ACTH increases (p values ≤ .044, ηp2 values ≥ 0.05). CONCLUSIONS: Cognitive stress appraisal processes seem to modulate RAAS stress reactivity. This points to potential clinical implications for psychoeducative therapeutical interventions targeting stress appraisal processes to reduce endocrine stress reactivity.

The Hippocampal-Ventral Medial Prefrontal Cortex Neurocircuitry Involvement in the Association of Daily Life Stress With Acute Perceived Stress and Cortisol Responses.

OBJECTIVE: Daily life stressors include everyday irritants, hassles, and inconveniences, such as problems in traffic and unexpected work deadlines. A growing body of research has suggested higher daily stress is associated with blunted cortisol response to acute psychosocial stressors. However, so far, the neural mechanism underlying this association has not been elucidated. The current study aimed to examine the role of stress neurocircuitry between the hippocampus and the ventral medial prefrontal cortex in this relationship. METHODS: To this end, as an index of daily stress in 44 young healthy individuals (23 females; mean [standard deviation] age = 19.07 [1.11] years), the total stressful rating score of daily life stress events that occurred in a 24-hour period was quantified. Individuals were then administered a modified version of the Montreal Imaging Stress Task while undergoing functional magnetic resonance imaging scans, and their saliva samples were collected for assessment of the stress hormone cortisol. RESULTS: Results revealed that a higher level of daily stress was associated with lower salivary cortisol secretion (r = -0.39, p = .008) and lower activation of the left hippocampus (tpeak = -5.51) in response to the Montreal Imaging Stress Task. Furthermore, a higher level of daily stress was associated with stronger functional connectivity between the left hippocampus and the ventral medial prefrontal cortex/subgenual anterior cingulate cortex (tpeak = 4.91, R2= 0.365). CONCLUSIONS: Taken together, the current study suggested a possible neurocircuitry of the hippocampus and ventral medial prefrontal cortex in the relationship between daily life stress and acute psychosocial stress.

Stress and Stress-Induced Glucocorticoids Facilitate Empathic Accuracy in Men but Have No Effects for Women.

Empathy, the ability to understand the feelings of other people, is critical for navigating our social world and maintaining social connections. Given that acute stress, and resulting increased glucocorticoids, triggers a shift in two large-scale brain networks, prioritizing salience over executive control, we predicted that acute psychosocial stress would facilitate empathic accuracy. We also investigated the moderating role of gender, given that men typically show a more robust glucocorticoid response to acute stress than women. As predicted, results from two independent experiments (N = 267 college-age participants; 2,256 observations) showed that acute psychosocial stress facilitated empathic accuracy for men, an effect related to their glucocorticoid response in the stress condition. Conversely, psychosocial stress had no effect on empathic accuracy for women, who also showed a smaller cortisol response to stress than men. Exploratory analyses further revealed that women taking oral contraceptives performed worse on the empathic-accuracy task than regularly cycling women. This research highlights the important, but complex, role of stress in cognitive empathy.

[Psychometric Properties of a German Translation of the Parental Bonding Instrument]. / Psychometrische Kennwerte einer deutschen Übersetzung des Parental Bonding Instrument.

Parenting behavior affects a child's development as well as the etiology and treatment of mental disorders. The Parental Bonding Instrument (PBI; Parker, Tupling & Brown, 1979) is a well-known measurement tool to retrospectively assess parenting styles. Yet, no sufficiently validated German version exists to date. Therefore, we developed an updated translation of the German PBI version (PBI-dt) and analyzed its psychometric properties in an online survey based on a sample of n=791 German-speaking participants with a focus on item and reliability characteristics, construct and criterion validity as well as factorial structure of the PBI-dt.Our results indicated good item characteristics and reliability (α=0.86-0.95). Correlations between PBI and CTQ-SF (Childhood Trauma Questionnaire Short Form) scales were in line with the literature. Significant differences in the reported parenting style were found between people with and without mental illness as well as between normal-weight and overweight people. These results indicated the presence of good construct and criterion validity. Confirmatory factor analyses indicated an acceptable model fit for all fit indices in the original 2-factor model of Parker et al. (1979) as well as in the 3-factor model with the scales CareCareCareCareCareCare, Discouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedomDiscouragement of behavioral freedom and Denial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomyDenial of psychological autonomy. A 3-factor structure provided additional information, e. g., a better differentiation between normal and overweight people. Hence, this German translation of the PBI has good psychometric properties and is a reliable measuring instrument.

Laughter yoga reduces the cortisol response to acute stress in healthy individuals.

Stress is one of the foremost contributors to the development of psychiatric diseases. Since the prevalence of stress-related complaints is increasing, we are in need for affordable and effective treatment alternatives. Laughter yoga (LY), a popular method encouraging participants to simulate laughter and participate in yogic breathing exercises, is hypothesized to buffer negative effects of stress. Although widely practiced, empirical evidence for beneficial effects of LY is scarce. We investigated the acute effects of a single 30-min LY session on the autonomic, endocrine and psychological response to a standardized psychosocial stressor. Thirty-five healthy subjects (51% female) were randomly assigned to experience either a LY (n = 11), a relaxation breathing (n = 12) or a (non-intervention) control (n = 12) session prior to their exposure to the Trier Social Stress Test for Groups (TSST-G). Salivary cortisol, salivary alpha amylase, and subjective stress were assessed repeatedly throughout the experiment. We expected that LY and relaxation breathing group each show a downregulation of stress response indices compared to the control group. Further, we expected that LY has beneficial effects compared to relaxation breathing. The groups did not differ in salivary cortisol, alpha amylase or subjective stress reactivity during the 30-min intervention. However, in response to the TSST-G, the LY, but neither the relaxation breathing, nor the control condition, showed an attenuated cortisol stress response. These findings highlight the potential of LY to buffer the endocrine stress response. Therefore, LY could be used as a cheap and easily-to-implement add-on to more traditional stress interventions. LAY SUMMARY In recent years, more and more people have reported to feel stressed. Although our body is well equipped to deal with acute stress, chronic stress can tire our system and contribute to illness in the long run. Therefore, we need affordable and effective measures to reduce stress. In this study we have investigated whether a single laughter yoga session can help us to deal with acute stress. Although laughter yoga did not change how stressful a situation was perceived, it reduced the amount of stress hormones that were released in response to the situation. As such, laughter yoga might be a cheap and easily-to-implement add-on to more traditional stress reduction interventions.

Interaction of FKBP5 variant rs3800373 and city living alters the neural stress response in the anterior cingulate cortex.

Psychosocial stress effects of urban living are associated with substantially increased risk for schizophrenia, mood and anxiety disorders, by altering stress-induced activity in the amygdala and pregenual anterior cingulate cortex (ACC). Genetic factors are likely to modulate the impact of city living on stress processing. Growing evidence suggests a key role of FKBP5, a co-chaperone regulating the glucocorticoid receptor sensitivity, in the etiology of stress-related disorders. Here we investigated the interaction of city living and genetic variation in FKBP5 (rs3800373) on neural activity in stress-sensitive brain systems. Functional magnetic resonance imaging was performed in 31 healthy young adults using the Montreal Imaging Stress Task. Subjects were divided into groups depending on the number of inhabitants of their current residency. There was a significant main effect of city living on neural activity in the amygdala-hippocampus complex, replicating prior findings. Moreover, we found an interaction between rs3800373 and city living modulating responses in the bilateral subgenual ACC and right pregenual ACC. Specifically, only city dwellers carrying the FKBP5 minor risk allele showed increased stress responses in the subgenual and pregenual ACC when compared to those living in small towns. A significant gene-environment interaction on neural stress responses in the amygdala or hippocampus was only found in FKBP5 major allele carriers. These results point to a potential role of the FKBP5 rs3800373 minor risk allele in predisposing those who live in bigger cities to changes of functional responsivity in the pre- and subgenual ACC, thereby increasing the risk for developing stress-related mental disorders.

The impact of maternal care and blood glucose availability on the cortisol stress response in fasted women.

Individuals with a history of low maternal care (MC) frequently present a blunted, yet sometimes also show an increased cortisol stress response. Fasted individuals with low blood glucose levels who are exposed to acute stress typically show an attenuated response pattern in this endocrine marker. Despite well-documented metabolic dysregulations after low MC, a possible interaction of both factors has not been investigated yet. Here, we examined the effects of MC and blood glucose concentration on various aspects of the stress response. Fasted women (N = 122, meanage = 22.12, sdage = 2.56) who experienced either very high, high, or low MC (based on the Parental Bonding Instrument) were randomly assigned to consume grape juice (condition sugar), or water (condition water) prior to being exposed to the Trier-Social-Stress-Test for groups. Salivary cortisol and alpha amylase, blood glucose, and mood ratings were assessed repeatedly. Using multilevel mixed models, we replicated the boosting effect of glucose on the cortisol stress response. While we found neither an effect of MC, nor an interaction between MC and blood glucose availability on the cortisol stress response, we observed an effect of MC on the amylase stress response. We discuss the results in the light of links between various stress/energy systems that possibly mediate health-related MC effects.

Influence of stress on physiological synchrony in a stressful versus non-stressful group setting.

Physiological synchrony (PS) is defined as the co-occurrence and interdependence of physiological activity between interaction partners. Previous research has uncovered numerous influences on the extent of PS, such as relationship type or individual characteristics. Here, we investigate the influence of acute stress on PS. We do so in a setting in which PS was not promoted, but contact between group members was explicitly minimized. We reanalyzed cortisol, alpha-amylase, and subjective stress data from 138 participants (mean age = [Formula: see text], 47.1% female) who previously underwent the Trier Social Stress Test for groups (TSST-G) or a non-stressful control task together, collected as part of a larger project by Popovic et al. (Sci Rep 10: 7845, 2020). Using a stability and influence model, an established method to test for synchrony, we tested whether individuals' cortisol and alpha-amylase concentrations could be predicted by group members' levels. We found cortisol PS in participants who were in the same group, the extent of which was stronger in the non-stressful control condition. For alpha-amylase, participants were synchronized as well; furthermore, there was an interaction between previous stress levels and PS. This suggests that while synchrony of both stress markers can occur in group settings even with spurious interaction, stressor exposure might attenuate its extent. We argue that if PS occurs in a sample where interaction was minimal, the phenomenon might be more widespread than previously thought. Furthermore, stressor exposure might influence whether a situation allows for PS. We conclude that PS should be investigated within group settings with various degrees of social interaction to further expose mechanisms of and influence on PS.

Relationship between déjà vu experiences and recognition-memory impairments in temporal-lobe epilepsy.

Déjà vu is characterised by feelings of familiarity and concurrent awareness that this familiarity is wrong. Previous neuropsychological research has linked déjà vu during seizures in individuals with unilateral temporal-lobe epilepsy (uTLE) to rhinal-cortex abnormalities, and to recognition-memory deficits that selectively affect familiarity assessment. Here, we examined whether bilateral TLE patients with déjà vu (bTLE) show a similar pattern of performance. Using two experimental tasks, we found that bTLE patients exhibit deficits not only for familiarity but also for recollection. Relative to uTLE, this broader impairment also involved hippocampal abnormalities. Our findings confirm rhinal-cortex contributions to the generation of false familiarity in déjà vu that parallel its contributions to familiarity on recognition-memory tasks. While they do not rule out a role for recollection in identifying this familiarity as wrong, the deficits observed in bTLE patients weigh against the notion that any such role is necessary for déjà vu to occur.

Stressed connections: cortisol levels following acute psychosocial stress disrupt affiliative mimicry in humans.

Mimicry, and especially spontaneous facial mimicry, is a rudimentary element of social-emotional experience that is well-conserved across numerous species. Although such mimicry is thought to be a relatively automatic process, research indicates that contextual factors can influence mimicry, especially in humans. Here, we extend this work by investigating the effect of acute psychosocial stress on spontaneous facial mimicry. Participants performed a spontaneous facial mimicry task with facial electromyography (fEMG) at baseline and approximately one month later, following an acute psychosocial stressor (Trier Social Stress Test). Results show that the magnitude of the endocrine stress response reduced zygomaticus major reactivity, and specifically spontaneous facial mimicry for positive social stimuli (i.e. smiles). Individuals with higher levels of the stress hormone cortisol showed a more blunted fEMG response to smiles, but not to frowns. Conversely, stress had no effect on corrugator supercilii activation (i.e. frowning to frowns). These findings highlight the importance of the biological stress response system in this basic element of social-emotional experience.

Brain Marker Links Stress and Nicotine Abstinence.

BACKGROUND: Subjective stress is a well-documented predictor of early smoking relapse, yet our understanding of stress and tobacco use is limited by reliance on self-reported measures of stress. We utilized a validated functional neuroimaging paradigm to examine whether stress exposure during early abstinence alters objective measures of brain function. METHODS: Seventy-five participants underwent blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) during the Montreal Imaging Stress Task (MIST) on two occasions: once during smoking satiety and once following biochemically confirmed 24-hour abstinence (order counterbalanced). The primary outcome measure was brain response during stress (vs. control) blocks of the MIST, assessed using whole-brain analysis corrected for multiple comparisons using clusters determined by Z ≥ 3.1. RESULTS: Abstinence (vs. satiety) was associated with significantly increased activation in the left inferior frontal gyrus, a brain region associated with inhibitory control. Abstinence-induced change in brain response to stress was positively associated with change in self-reported stress. CONCLUSIONS: This study provides objective evidence that the brain response to stress is altered during the first 24 hours of a quit attempt compared to smoking satiety. IMPLICATIONS: These results point to the potential value of inoculating smokers with stress management training prior to a quit attempt.

Stress-induced cortical dopamine response is altered in subjects at clinical high risk for psychosis using cannabis.

Stress and cannabis use are risk factors for the development of psychosis. We have previously shown that subjects at clinical high risk for psychosis (CHR) exhibit a higher striatal dopamine response to stress compared with healthy volunteers (HV), with chronic cannabis use blunting this response. However, it is unknown if this abnormal dopamine response extends to the prefrontal cortex (PFC). Here, we investigated dorsolateral PFC (dlPFC) and medial PFC (mPFC) dopamine release using [11 C]FLB457 positron emission tomography (PET) and a validated stress task. Thirty-three participants completed two PET scans (14 CHR without cannabis use, eight CHR regular cannabis users [CHR-CUs] and 11 HV) while performing a Sensory Motor Control Task (control scan) and the Montreal Imaging Stress Task (stress scan). Stress-induced dopamine release (ΔBPND ) was defined as percent change in D2/3 receptor binding potential between both scans using a novel correction for injected mass of [11 C]FLB457. ΔBPND was significantly different between groups in mPFC (F(2,30) = 5.40, .010), with CHR-CUs exhibiting lower ΔBPND compared with CHR (.008). Similarly, salivary cortisol response (ΔAUCI ) was significantly lower in CHR-CU compared with CHR (F(2,29) = 5.08, .013; post hoc .018) and positively associated with ΔBPND . Furthermore, CHR-CUs had higher attenuated psychotic symptoms than CHR following the stress task, which were negatively associated with ΔBPND . Length of cannabis use was negatively associated with ΔBPND in mPFC when controlling for current cannabis use. Given the global trend to legalize cannabis, this study is important as it highlights the effects of regular cannabis use on cortical dopamine function in high-risk youth.

The hippocampal-to-ventricle ratio (HVR): Presentation of a manual segmentation protocol and preliminary evidence.

Disentangling age-related changes from developmental variations in hippocampal volume has proven challenging. This article presents a manual segmentation protocol for the hippocampal-to-ventricle ratio (HVR), a measure combining the assessment of hippocampal volume with surrounding ventricular volume. By providing in a single measure both a standard volumetric assessment of the hippocampus and an approximation of volume loss, based on ventricular enlargement, we believe the HVR provides a superior cross-sectional estimation of hippocampal structural integrity. In a first attempt to validate this measure, we contrasted the HVR and standard hippocampal volume in their associations with age and memory performance in two independent cohorts of healthy aging individuals. The first cohort consisted in 50 cognitively normal subjects (mean age: 66.8 years, SD: 4.96, range: 60-75 years), while the second cohort included 88 cognitively normal subjects (mean age: 65.06 years, SD: 6.42, range: 55-80 years). We showed that the manual segmentation protocol for the HVR can be implemented with high reliability. In both cohorts, the HVR showed stronger negative associations with age than standard hippocampal volume. Correlations with memory performance were also numerically superior with the HVR than standard hippocampal volume, across the two cohorts. These findings support an added benefit of using the HVR over standard hippocampal volume when examining relationships with age or memory function in aging individuals. Although further validation is required, we propose that the computation of the HVR is a promising method to improve the evaluation of hippocampal integrity from cross-sectional MR images.

Dance your stress away: comparing the effect of dance/movement training to aerobic exercise training on the cortisol awakening response in healthy older adults.

This study aimed to examine in healthy older adults the effects of dance/movement training (DMT) on the cortisol awakening response (CAR), a marker of chronic stress. Forty participants (mean age = 67.45, 75% women) were randomized into three groups: DMT (n = 12) - a set of exercises to promote gross motor skills, body awareness, and socialization; aerobic exercise training (AT; n = 14) - high intensity activity on a recumbent bicycle, and wait list (WL; n = 14). Both DMT and AT groups were supervised by licensed instructors and met three times a week for three months. Before and after their respective program, participants of all groups provided saliva samples on 3 d at 0-, 30- and 60-min after awakening, and had their fitness level evaluated. A significant group × time interaction (F(2,34) = 5.79, p = .01, η2partial = 0.25) was found, with the DMT group showing lower salivary cortisol values post-training, while the other two groups showed no change from baseline in their CAR. Cardiorespiratory fitness improved only in the AT group, while DMT showed no group-specific physical functioning improvements. The results are discussed in terms of the importance of physical and psychological effects of training on change in cortisol levels.

The EADC-ADNI harmonized protocol for hippocampal segmentation: A validation study.

Recently, a group of major international experts have completed a comprehensive effort to efficiently define a harmonized protocol for manual hippocampal segmentation that is optimized for Alzheimer's research (known as the EADC-ADNI Harmonized Protocol (the HarP)). This study compares the HarP with one of the widely used hippocampal segmentation protocols (Pruessner, 2000), based on a single automatic segmentation method trained separately with libraries made from each manual segmentation protocol. The automatic segmentation conformity with the corresponding manual segmentation and the ability to capture Alzheimer's disease related hippocampal atrophy on large datasets are measured to compare the manual protocols. In addition to the possibility of harmonizing different procedures of hippocampal segmentation, our results show that using the HarP, the automatic segmentation conformity with manual segmentation is also preserved (Dice's κ=0.88,κ=0.87 for Pruessner and HarP respectively (p = 0.726 for common training library)). Furthermore, the results show that the HarP can capture the Alzheimer's disease related hippocampal volume differences in large datasets. The HarP-derived segmentation shows large effect size (Cohen's d = 1.5883) in separating Alzheimer's Disease patients versus normal controls (AD:NC) and medium effect size (Cohen's d = 0.5747) in separating stable versus progressive Mild Cognitively Impaired patients (sMCI:pMCI). Furthermore, the area under the ROC curve for a LDA classifier trained based on age, sex and HarP-derived hippocampal volume is 0.8858 for AD:NC, and for 0.6677 sMCI:pMCI. These results show that the harmonized protocol-derived labels can be widely used in clinic and research, as a sensitive and accurate way of delineating the hippocampus.

Manual segmentation of the fornix, fimbria, and alveus on high-resolution 3T MRI: Application via fully-automated mapping of the human memory circuit white and grey matter in healthy and pathological aging.

Recently, much attention has been focused on the definition and structure of the hippocampus and its subfields, while the projections from the hippocampus have been relatively understudied. Here, we derive a reliable protocol for manual segmentation of hippocampal white matter regions (alveus, fimbria, and fornix) using high-resolution magnetic resonance images that are complementary to our previous definitions of the hippocampal subfields, both of which are freely available at https://github.com/cobralab/atlases. Our segmentation methods demonstrated high inter- and intra-rater reliability, were validated as inputs in automated segmentation, and were used to analyze the trajectory of these regions in both healthy aging (OASIS), and Alzheimer's disease (AD) and mild cognitive impairment (MCI; using ADNI). We observed significant bilateral decreases in the fornix in healthy aging while the alveus and cornu ammonis (CA) 1 were well preserved (all p's<0.006). MCI and AD demonstrated significant decreases in fimbriae and fornices. Many hippocampal subfields exhibited decreased volume in both MCI and AD, yet no significant differences were found between MCI and AD cohorts themselves. Our results suggest a neuroprotective or compensatory role for the alveus and CA1 in healthy aging and suggest that an improved understanding of the volumetric trajectories of these structures is required.

Interdependent self-construal, social evaluative threat and subjective, cardiovascular and neuroendocrine stress response in Chinese.

Interdependent self-construal (ISC) is a concept positing that people define their self through social roles and relationships with others. We investigated in two independent studies whether ISC had an effect on psychological and endocrine stress responses. Study 1 collected data of 295 healthy young Chinese participants' subjective report of ISC using the self-construal scale, and daily levels of stress using the daily stress inventory. Correlational analyses showed that individuals with higher ISC perceived higher levels of stress in daily life. Study 2 added biological measures of stress by analyzing both basal cortisol levels and reactive cortisol level of high/low ISC individuals (23 high and 23 low ISC healthy young Chinese participants recruited from a total of 440 participants), in response to the Trier Social Stress test. Participants with high ISC showed higher cortisol stress responses, higher heart rate measurements, and higher subjective stress reports when compared to low ISC participants. Further analyses suggested that participants' perception of social evaluative threat mediated the association between ISC and the cortisol stress response. Taken together, these findings suggest a significant role of ISC in regulating the biological and psychological stress response. These findings are discussed in the context of other personality factors known to affect the stress response, and the cultural-related self-construal literature. We also discuss the possible application of the ISC personality factor for future stress studies.