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Excessive monitoring of one's performance is a characteristic of anxiety disorders that has been linked to alterations in implicit emotion regulation (ER), including elevations in neural measures of performance monitoring (i.e., error- and correct-related negativity; ERN and CRN). Elevations in ERN and CRN amplitudes have been reported consistently in anxiety disorders, suggesting that an overactive performance monitoring system is linked to ER difficulties in anxiety. Yet, the relevance of these lab-based neural measures for day-to-day emotional functioning remains poorly understood. This study examined the degree to which ERN and CRN amplitudes are associated with measures of daily ER difficulties in youth with anxiety disorders. Youth (N=100, Mage=11.14, SDage=1.46) completed a computerized flanker task assessing the ERN and CRN. They then completed a 5-day ecological momentary assessment (EMA) protocol assessing their daily ER (i.e., intensity of momentary and peak negative affect, intensity of worry, reliance on maladaptive ER strategies). Results showed that more negative mean CRN amplitudes were associated with higher levels of negative emotional reactivity and more intense worries. There were no significant associations between ERN amplitude and EMA measures. Furthermore, elevations in CRN were linked to more frequent use of maladaptive ER strategies (i.e., rumination, physiological reactivity, avoidance). Together, results indicate that among youth with anxiety, individual differences in CRN, but not ERN, amplitudes are related to daily ER difficulties. Findings highlight the clinical utility of a lab-based neural measure of ER, suggesting that the CRN, rather than the ERN, reflects individual ER differences in the context of daily life among youth with pediatric anxiety disorders. As such, the CRN might serve as an important dimensional index of a treatment target that can be tracked with a validated, multi-method measure.

Developmental prosopagnosia (DP) is a neurodevelopmental disorder associated with difficulties in the perception and recognition of faces. However, the extent to which DP affects non-face object is an ongoing debate. In this study, we asked whether pareidolic objects (which give rise to the perception of a face) are also affected in DP. First, we compared performance in DPs (n = 30) and controls (n = 27) on a recognition task with faces, pareidolic objects and non-pareidolic objects (bottles). The pareidolic objects had either similar or dissimilar image statistics to faces. Consistent with our understanding of DP, we found that the pattern of recognition across items between DPs and controls was lowest for faces. Interestingly, there was also a low correlation between DPs and controls for pareidolic-similar objects that was similar to faces. In contrast, there were higher correlations between DPs and controls for pareidolic-dissimilar objects and bottles, which were both significantly different to faces. These findings suggest that the deficit in DP involves processing image properties that are common to faces. Next, using an individual differences approach across a large group of neurotypical adults (n = 94), we found that face recognition covaried with the recognition of pareidolic-similar objects, but not with pareidolic-dissimilar objects or non-pareidolic objects. Together, these findings support the idea that a representation based on image properties plays an important role in the perception and recognition of objects and faces and that the deficit in the perception of some object categories in DP could be explained by their similarity to the image properties found in faces.

Young adolescents are hypothesized to differ in their environmental sensitivity, at both phenotypic (i.e., Sensory Processing Sensitivity [SPS]) and physiological (i.e., biological stress response) level. This is the first study that investigated whether individual differences in environmental sensitivity at physiological level could be predicted by individual differences at phenotypic level, as measured with the HSC scale. A total of 101 adolescents (Mage = 11.61, SDage = 0.64) participated in a standardized social stress task (i.e., Trier Social Stress Task-Modified version for children and adolescents (TSST-M)). From baseline to the end of recovery, eight cortisol samples were collected, as well as a continuous measure of Autonomic Nervous System activity. Adolescents reported on SPS and on perceived stress before, during, and after TSST-M. As a follow-up analysis, the quality of the environment, the possible overlap with Neuroticism, and several covariates were considered. Multilevel models were used to investigate within- and between-person differences in stress reactivity across different systems. Results indicate significant individual differences in heart rate, heart rate variability, skin conductance, cortisol, and perceived stress in response to the TSST-M. Only for perceived stress significant differences in SPS were observed, with more sensitive individuals perceiving more negative and less positive affect. For environmental quality and the interaction between SPS and Neuroticism results showed higher recovery rates of heart rate in high quality environments and stronger cortisol responses for adolescents scoring high on both SPS and Neuroticism. Potential explanations for these findings and implications for current theorizing on environmental sensitivity are discussed. ispartof: International Journal Of Psychophysiology vol:176 pages:36-53 ispartof: location:Netherlands status: published

How do different measures of brain structure correlate with individual differences in arithmetic fluency? This paper builds on two previously published studies in which individual differences in children's arithmetic fluency were correlated with measures of white ( Polspoel et al., 2019 ) and grey matter ( Polspoel et al., 2020 ) in one sample of children. We combined the brain imaging data of these two studies with measures of cognitive abilities that have been shown to be predictive of arithmetic fluency, i.e., numerical magnitude processing, working memory and rapid automatized naming (RAN). This allowed us to investigate to which extend the observed structural brain imaging measures uniquely correlated with children's arithmetic fluency, on top of each other as well as on top of the abovementioned cognitive variables. Participants were 43 typically developing 9-10-year-olds. All measures were added to a hierarchical multiple regression model. This regression model showed that the white matter integrity of the right inferior longitudinal fasciculus and the cortical complexity of the left postcentral gyrus remained unique predictors of individual differences in arithmetic when the abovementioned cognitive variables were taken into account. This indicates that structural neuroimaging measures can explain individual differences in arithmetic performance that are not merely accounted for by relevant cognitive predictors.

Perceptual experience in the recent past has been shown to alter subsequent perception. Recently, it has been suggested that this "serial dependence" effect is modulated by sensory uncertainty. In the current study, by overlaying three different levels of visual noise (i.e., no-, low-, or high-noise) on face stimuli, we investigated how serial dependence in face identity perception varies with sensory uncertainty. After learning two facial identities, the faces were combined at various morph levels and participants reported which identity was perceived while noise and noise-free presentations alternated over trials. Results showed that identity perception of noise-free faces was positively biased toward the past when the previous face was noise-free or highly noisy, but not when a low-noise was added. There were considerable individual differences in bias magnitude for trials preceded by high-noise stimuli which reflected individuals' general bias tendencies. When correlated with the other two conditions, a general bias tendency showed a significant relationship with low-noise trials, but not with no-noise trials. This indicates that the bias tendency of individuals manifests more strongly when the sensory information was uncertain. Therefore, the current findings suggest 1) that sensory uncertainty modulates serial dependence in face identity perception and 2) that an individual's general bias tendency interacts with sensory uncertainty to alter perception.

Although DNA repair is known to impact susceptibility to cancer and other diseases, relatively few population studies have been performed to evaluate DNA repair kinetics in people due to the difficulty of assessing DNA repair in a high throughput manner. Here we use the CometChip, a high throughput comet assay, to explore inter-individual variation in repair of oxidative damage to DNA, a known risk factor for aging, cancer and other diseases. DNA repair capacity after H(2)O(2)-induced DNA oxidation damage was quantified in peripheral blood mononuclear cells (PBMCs). For 10 individuals, blood was drawn at several times over the course of 4-6 weeks. In addition, blood was drawn once from each of 56 individuals. DNA damage levels were quantified prior to exposure to H(2)O(2) and at 0, 15, 30, 60, and 120-minutes post exposure. We found that there is significant variability in DNA repair efficiency among individuals. When subdivided into quartiles by DNA repair efficiency, we found that the average t(1/2) is 81 minutes for the slowest group and 24 minutes for the fastest group. This work shows that the CometChip can be used to uncover significant differences in repair kinetics among people, pointing to its utility in future epidemiological and clinical studies.

BACKGROUND: Noninvasive transcranial electrical stimulation (tES) research has been plagued with inconsistent effects. Recent work has suggested neuroanatomical and neurophysiological variability may alter tES efficacy. However, direct evidence is limited. OBJECTIVE: We have previously replicated effects of transcranial alternating current stimulation (tACS) on improving multitasking ability in young adults. Here, we attempt to assess whether these stimulation parameters have comparable effects in older adults (aged 60–80 years), which is a population known to have greater variability in neuroanatomy and neurophysiology. It is hypothesized that this variability in neuroanatomy and neurophysiology will be predictive of tACS efficacy. METHODS: We conducted a pre-registered study where tACS was applied above the prefrontal cortex (between electrodes F3-F4) while participants were engaged in multitasking. Participants were randomized to receive either 6-Hz (theta) tACS for 26.67 minutes daily for three days (80 minutes total; Long Exposure Theta group), 6-Hz tACS for 5.33 minutes daily (16-minutes total; Short Exposure Theta group), or 1-Hz tACS for 26.67 minutes (80 minutes total; Control group). To account for neuroanatomy, magnetic resonance imaging data was used to form individualized models of the tACS-induced electric field (EF) within the brain. To account for neurophysiology, electroencephalography data was used to identify individual peak theta frequency. RESULTS: Results indicated that only in the Long Theta group, performance change was correlated with modeled EF and peak theta frequency. Together, modeled EF and peak theta frequency accounted for 54% – 65% of the variance in tACS-related performance improvements, which sustained for a month. CONCLUSION: These results demonstrate the importance of individual differences in neuroanatomy and neurophysiology in tACS research and help account for inconsistent effects across studies.

Functional MRI (fMRI) has considerable potential as a translational tool for understanding risk, prioritizing interventions, and improving the treatment of brain disorders. However, recent studies have found that many of the most widely used fMRI measures have low reliability, undermining this potential. Here, we argue that many fMRI measures are unreliable because they were designed to identify group-effects, not to precisely quantify individual differences. We then highlight four emerging strategies (extended aggregation, reliability modeling, multi-echo fMRI, and stimulus design) that build on established psychometric properties to generate more precise and reliable fMRI measures. By adopting such strategies to improve reliability, we are optimistic that fMRI can fulfill its potential as a clinical tool.

Crown Copyright © 2022. This study examined the effects of explicit versus implicit learning methods on motor learning and self-efficacy of 11-to 14-year old students (n = 81) practicing the basketball layup during physical education. The main aim was to test the effects of students' verbal working memory capacity (WMC) and propensity for conscious motor processing (CMP) on explicit and implicit learning outcomes. The students practiced basketball layups for three weeks (one session/week) during regular PE classes under practice conditions that either promoted explicit or implicit learning. Verbal WMC and CMP propensity were measured separately. At the posttest, students had significantly improved their layup performance and technique, and self-efficacy, but no differences were noted between the intervention groups (explicit vs. implicit). Students' verbal WMC and CMP propensity did not differentially predict the learning outcomes for the explicit or implicit learning groups. Therefore, in this PE setting, both explicit and implicit learning methods seemed to similarly improve movement skill. Further study is needed to examine under which conditions individual constraints such as verbal WMC and propensity for conscious processing influence the effects of explicit and implicit learning.

Better sleep quality has been associated with better episodic memory performance in young adults. However, the strength of sleep-memory associations in aging has not been well characterized. It is also unknown whether factors such as sleep measurement method (e.g., polysomnography, actigraphy, self-report), sleep parameters (e.g., slow wave sleep, sleep duration), or memory task characteristics (e.g., verbal, pictorial) impact the strength of sleep-memory associations. Here, we assessed if the aforementioned factors modulate sleep-memory relationships. Across age groups, sleep-memory associations were similar for sleep measurement methods, however, associations were stronger for PSG than self-report. Age group moderated sleep-memory associations for certain sleep parameters. Specifically, young adults demonstrated stronger positive sleep-memory associations for slow wave sleep than the old, while older adults demonstrated stronger negative associations between greater wake after sleep onset and poorer memory performance than the young. Collectively, these data show that young and older adults maintain similar strength in sleep-memory relationships, but age impacts the specific sleep correlates that contribute to these relationships.

Multi-national and meta-analytic studies suggest that the pathways between religiousness and sexism/sexual prejudice are partially mediated by sociopersonality factors such as conservatism. In this article, we describe the contributing factors to this relationship, such as authoritarianism and fundamentalism. These factors interact at the dynamic nexus of individual and social development. As such, religiously situated sexism and sexual prejudice are not viewed as inevitable outcomes to religious practice and faith. Individual differences (e.g. conservatism), congregational (e.g. doctrine/policies, limited contact), and cultural factors (e.g. power hierarchies) mutually contribute to this landscape, and individuals ultimately make choices regarding their behavior and views. Further research exploring the mechanisms of religiously situated gender inequality and sexual prejudice is essential given the associated negative outcomes for individuals, relationships, and communities. Our growing grasp of the agentive pathways leading to religiously situated prejudice and discrimination is enriching our understanding of how individual differences and social contexts contribute to sexism and sexual prejudice.

There are considerable individual differences in visual mental imagery ability across the general population, including a “blind” mind’s eye, or aphantasia. Recent studies have shown that imagery is linked to differences in perception in the healthy population, and clinical work has found a connection between imagery and hallucinatory experiences in neurological disorders. However, whether imagery ability is associated with anomalous perception – including hallucinations – in the general population remains unclear. In the current study, we explored the relationship between imagery ability and the anomalous perception of pseudo-hallucinations (PH) using rhythmic flicker stimulation (“Ganzflicker”). Specifically, we investigated whether the ability to generate voluntary imagery is associated with susceptibility to flicker-induced PH. We additionally explored individual differences in observed features of PH. We recruited a sample of people with aphantasia (aphants) and imagery (imagers) to view a constant red-and-black flicker for approximately 10 minutes. We found that imagers were more susceptible to PH, and saw more complex and vivid PH, compared to aphants. This study provides compelling evidence that the ability to generate visual imagery increases the likelihood of experiencing complex and vivid anomalous percepts.

Biological (BA) and chronological (CA) age may or may not fit. The available evidence reveals remarkable individual differences in the overlap/mismatch between BA and CA. Increased mismatch can be interpreted as delayed (BA/CA 1) or accelerated biological aging (BA/CA 1). Body and brain health are correlated and both predict aging outcomes associated with physical and mental fitness. Moreover, research has shown that older brain age at midlife correlates negatively with cognitive ability measured in early childhood, which suggests early life predisposition to accelerated aging in adulthood. Under this framework, here we test if increased cognitive ability is associated with delayed brain aging, analyzing structural MRI data of 188 individuals, sixty of whom were recruited from MENSA, an association comprising individuals who obtained cognitive ability scores in the top 2 percent of the population. These high ability individuals (HCA) showed an average advantage of 33 IQ points, on a fluid reasoning test they completed for this research, over those other recruited because of their average cognitive ability (ACA). Next, brain age was computed at the individual level for two distinguishable neocortical features (thickness and surface area) according to models trained in an independent large-scale sample of 2377 individuals. Results revealed a stronger pattern of accelerated brain aging in HCA compared to ACA individuals for thickness, while the opposite pattern was suggested for surface area. The findings align well with the greater relevance of individual differences in cortical surface area for enhancing our understanding of cognitive differences at the brain level.

A critical question regards the neural basis of complex cognitive skill acquisition. One extensively studied skill is navigation, with evidence suggesting that humans vary widely in navigation abilities. Yet, data supporting the neural underpinning of these individual differences are mixed. Some evidence suggests robust structure-behavior relations between hippocampal volume and navigation ability, whereas other experiments show no such correlation. We focus on several possibilities for these discrepancies: 1) volumetric hippocampal changes are relevant only at the extreme ranges of navigational abilities; 2) hippocampal volume correlates across individuals but only for specific measures of navigation skill; 3) hippocampal volume itself does not correlate with navigation skill acquisition; connectivity patterns are more relevant. To explore this third possibility, we present a model emphasizing functional connectivity changes, particularly to extra-hippocampal structures. This class of models arises from the premise that navigation is dynamic and that good navigators flexibly solve spatial challenges. These models pave the way for research on other skills and provide more precise predictions for the neural basis of skill acquisition.

Anomalous trichromats have three classes of cone receptors but with smaller separation in the spectral sensitivities of their longer-wave (L or M) cones compared to normal trichromats. As a result, the differences in the responses of the longer-wave cones are smaller, resulting in a weaker input to opponent mechanisms that compare the LvsM responses. Despite this, previous studies have found that their color percepts are more similar to normal trichromats than the smaller LvsM differences predict, suggesting that post-receptoral processes might amplify their responses to compensate for the weaker opponent inputs. We evaluated the degree and form of compensation using a hue-scaling task, in which the appearance of different hues is described by the perceived proportions of red-green or blue-yellow primary colors. The scaling functions were modeled to estimate the relative salience of the red-green to blue-yellow components. The red-green amplitudes of the 10 anomalous observers were 1.5 times weaker than for a group of 26 normal controls. However, their relative sensitivity at threshold for detecting LvsM chromatic contrast was on average 6 times higher, consistent with a 4-fold gain in the suprathreshold hue-scaling responses. Within-observer variability in the settings was similar for the two groups, suggesting that the suprathreshold gain did not similarly amplify the noise, at least for the dimension of hue. While the compensation was pronounced it was nevertheless partial, and anomalous observers differed systematically from the controls in the shapes of the hue-scaling functions and the corresponding loci of their color categories. Factor analyses further revealed different patterns of individual differences between the groups. We discuss the implications of these results for understanding both the processes of compensation for a color deficiency and the limits of these processes.

Stop-signal reaction time (SSRT), the time needed to cancel an already-initiated motor response, quantifies individual differences in inhibitory control. Electrophysiological correlates of SSRT have primarily focused on late event-related potential (ERP) components over midline scalp regions from successfully inhibited stop trials. SSRT is robustly associated with the P300, there is mixed evidence for N200 involvement, and there is little information on the role of early ERP components. Here, machine learning was first used to interrogate ERPs during both successful and failed stop trials from 64 scalp electrodes at 4 ms resolution (n = 148). The most predictive model included data from both successful and failed stop trials, with a cross-validated Pearson's r of 0.32 between measured and predicted SSRT, significantly higher than null models. From successful stop trials, spatio-temporal features overlapping the N200 in right frontal areas and the P300 in frontocentral areas predicted SSRT, as did early ERP activity (200 ms). As a demonstration of the reproducibility of these findings, the application of this model to a separate dataset of 97 participants was also significant (r = 0.29). These results show that ERPs during failed stops are relevant to SSRT, and that both early and late ERP activity contribute to individual differences in SSRT. Notably, the right lateralized N200, which predicted SSRT here, is not often observed in neurotypical adults. Both the ascending slope and peak of the P300 component predicted SSRT. These results were replicable, both within the training sample and when applied to ERPs from a separate dataset.

Background Secure attachment is important in maintaining an individual’s health and well-being. Attachment disturbances increase the risk for developing psychiatric disorders such as affective disorders. Yet, the neurobiological correlates of human attachment are poorly understood at the neurotransmitter level. We investigated whether adult attachment style is linked to functioning of the opioid and serotonergic systems in the human brain. Methods We used positron emission tomography with radioligands [11C]carfentanil and [11C]MADAM to quantify mu opioid receptor (n = 39) and serotonin transporter (n = 37) availability in volunteers with no current psychiatric disorders. Attachment style was determined according to the Dynamic-Maturational Model of Attachment and Adaptation with the structured Adult Attachment Interview. Results Secure attachment was associated with higher mu opioid receptor availability in the hippocampus, amygdala, thalamus, and prefrontal cortex when compared with insecure (i.e., avoidant or ambivalent groups combined) attachment. In contrast, attachment style was not associated with serotonin transporter availability. Conclusions Our results provide preliminary in vivo evidence that the opioid system may be involved in the neurocircuits associated with individual differences in adult attachment behavior. The results suggest that variation in mu opioid receptor availability may be linked with the individuals’ social relationships and psychosocial well-being and thus contributes to risk for psychiatric morbidity.

Social inhibition may be associated with individual differences in emotion regulation. Mechanisms relating emotion regulation to social inhibition are largely unknown. We therefore examined how social inhibition is associated with emotional, sympathetic, and parasympathetic responses during sadness induction, and while employing emotion regulation strategies during social interaction after sadness induction. Undergraduate students (N = 216; 72% female) completed the Social Inhibition Questionnaire and participated in a sadness induction and emotion regulation (i.e., suppression and reappraisal) social interaction task, while emotional states, and sympathetic and parasympathetic reactivity were assessed. Repeated measures ANCOVAs showed that during sadness induction, social inhibition was unrelated to the emotional response, but social inhibition was associated with a blunted parasympathetic withdrawal response, due to an already withdrawn parasympathetic tone at rest. This may be suggestive of increased allostatic load with higher social inhibition, and may contribute to stress-related health risks. Both suppression and reappraisal tasks successfully diminished sadness, and this reduction was smaller with increasing levels of social inhibition. Physiological responses to emotion regulation efforts were independent of social inhibition. Elevated sadness in response to instructed emotion regulation in socially inhibited individuals may indicate more emotional distress during social interaction due to heightened threat sensitivity they experience.

Background Transcranial direct current stimulation (tDCS) is widely investigated as a therapeutic tool to enhance cognitive function in older adults with and without neurodegenerative disease. Prior research demonstrates that electric current delivery to the brain can vary significantly across individuals. Quantification of this variability could enable person-specific optimization of tDCS outcomes. This pilot study used machine learning and MRI-derived electric field models to predict working memory improvements as a proof of concept for precision cognitive intervention. Methods Fourteen healthy older adults received 20 minutes of 2 mA tDCS stimulation (F3/F4) during a two-week cognitive training intervention. Participants performed an N-back working memory task pre-/post-intervention. MRI-derived current models were passed through a linear Support Vector Machine (SVM) learning algorithm to characterize crucial tDCS current components (intensity and direction) that induced working memory improvements in tDCS responders versus non-responders. Main results SVM models of tDCS current components had 86% overall accuracy in classifying treatment responders vs. non-responders, with current intensity producing the best overall model differentiating changes in working memory performance. Median current intensity and direction in brain regions near the electrodes were positively related to intervention responses ( r = 0.811 , p 0.001 and r = 0.774 , p = 0.001 ). Conclusions This study provides the first evidence that pattern recognition analyses of MRI-derived tDCS current models can provide individual prognostic classification of tDCS treatment response with 86% accuracy. Individual differences in current intensity and direction play important roles in determining treatment response to tDCS. These findings provide important insights into mechanisms of tDCS response as well as proof of concept for future precision dosing models of tDCS intervention.

Theoretical accounts typically posit that variability in social behaviour is a function of capacity limits. We argue that many social behaviours are goal-directed and effortful, and thus variability is not just a function of capacity, but also motivation. Leveraging recent work examining the cognitive, computational and neural basis of effort processing, we put forward a framework for motivated social cognition. We argue that social cognition is demanding, people avoid its effort costs, and a core-circuit of brain areas that guides effort-based decisions in non-social situations may similarly evaluate whether social behaviours are worth the effort. Thus, effort sensitivity dissociates capacity limits from social motivation, and may be a driver of individual differences and pathological impairments in social cognition.

Background Locked-in syndrome (LIS) characterizes individuals who have experienced pontine lesions, who have limited motor output but with preserved cognitive abilities. Despite their severe physical impairment, individuals with LIS self-profess a higher quality of life than generally expected. Such third-person expectations about LIS are shaped by personal and cultural factors in western countries. Objective We sought to investigate whether such opinions are further influenced by the cultural background in East Asia. We surveyed attitudes about the ethics of life-sustaining treatment in LIS in a cohort of medical and non-medical Chinese participants. Results The final study sample included 1545 respondents: medical professionals (n = 597, 39%), neurologists (n = 303, 20%), legal professionals (n = 276, 18%) and other professionals (n = 369, 24%), including 180 family members of individuals with LIS. Most of the participants (70%), especially neurologists, thought that life-sustaining treatment could not be stopped in individuals with LIS. It might be unnecessary to withdraw life-sustaining treatment, because the condition involved is not terminal and irreversible, and physical treatment can be beneficial for the patient. A significant proportion (59%) of respondents would like to be kept alive if they were in that condition; however, older people thought the opposite. Families experience the stress of caring for individuals with LIS. The mean (SD) quality of life score for relatives was 0.73 (2.889) (on a −5, +5 scale), which was significantly lower than that of non-relatives, 1.75 (1.969) (P Conclusions Differences in opinions about end of life in LIS are affected by personal characteristics. The current survey did not identify a dissociation between personal preferences and general opinions, potentially because of a social uniformity in China where individualism is less pronounced. Future open-ended surveys could identify specific needs of caregivers so that strategic interventions to reduce ethical debasement are designed.

Introduction ATP binding cassette (ABC) membrane transporter multidrug resistance 1 (MDR1) is one of the most important efflux transporters in the human placenta protecting the fetus from exposure to xenobiotic toxicity. Recent studies have focused on placental MDR1 expression, but few studies have analyzed placental MDR1 transport activity. The purpose of this study was to investigate placental MDR1 transport activity using a relatively large sample size of human placentas. Furthermore, the effect of ABCB1 gene polymorphisms were investigated along with physiological factors including maternal age, times of pregnancy, BMI, delivery mode or pregnancy complications on placental MDR1 transport activity. Methods A total of 252 human placentas were obtained after delivery. MDR1 transport activity was detected by N-methyl quinidine uptake in placental microvillus membrane vesicles (MVMVs). Nine common single nucleotide polymorphisms (SNPs) in ABCB1 genes were determined by Snapshot. The association between ABCB1 gene polymorphisms, maternal age, times of pregnancy, BMI, delivery mode or pregnancy complications, and transporter activity was investigated. Results Inter-individual variations of MDR1 transport activity were observed among 252 subjects. The per unit protein activity was ranged from 0.05 to 0.15/mg. Nine SNPs in ABCB1 gene didn't exhibit significant association with transporter activity of MDR1. Likewise, neither age, times of pregnancy, delivery mode nor pregnancy complications showed any significant effect of placental MDR1 transport activity. But placental MDR1 transport activity in obese pregnant women was lower than those in non-obese pregnant women. Conclusion Inter-individual variations of MDR1 transport activity existed in human placentas. This may contribute to variations in drug exposure to the fetus affecting clinical outcomes. Maternal age, times of pregnancy, delivery mode nor pregnancy complications included in this study maybe not significantly impact placental MDR1 transport activity, but maternal obese could inhibit placental MDR1 activity.

This article synthesizes recent psychological research at the intersection of power, status, and culture. Our review shows that culture affects how status and power are conceptualized, who attains them, and what their consequences are. In individualistic cultures (and particularly vertical ones that emphasize hierarchical arrangements), power is conceptualized in personalized terms (i.e. focus on self-benefits), competence drives status attainment, norm violations increase power, and individuals strive primarily for power, approve of powerholders that behave equitably, and feel happy when they have personal power. In contrast, in collectivistic cultures (and particularly horizontal ones that promote egalitarianism), power is conceptualized in socialized terms (i.e. focus on benefitting others), warmth and competence drive status attainment, norm adherence increases power, and individuals strive primarily for status, approve of powerholders that behave compassionately, and feel happy when they have socialized power. We discuss what remains unknown as a mechanism for guiding future work.

This study argues that there exists, in the general population, a distinctive profile of cognitive traits that predisposes people to develop synaesthesia (termed a 'synaesthetic disposition'). This consists of more vivid mental imagery, better episodic memory, and greater attention-to-detail (amongst others things). Using a machine-learning classifier, we show that it is possible to distinguish synaesthetes from others using only standard cognitive and personality measures. Importantly, people with multiple forms of synaesthesia have a more distinctive profile (i.e., they can be more accurately classified). This suggests that whilst the presence/absence of synaesthesia is dichotomous, the underlying causal mechanisms are continuous. Moreover, we provide evidence that the cognitive profile constitutes a heritable endophenotype. Non-synaesthetic relatives of synaesthetes are cognitively similar to synaesthetes. This provides new insights into why synaesthesia might have evolved (i.e., it is possible to have the cognitive benefits of synaesthesia in the absence of the anomalous experiences). The notion of a synaesthetic disposition represents a novel, quantifiable individual difference in cognition/personality. This paves the way for determining if this is linked to a distinctive pattern of clinical vulnerabilities.

Exposure to stress has a variety of consequences on human behavior and cognition. Although widely investigated, the impact of stress on working memory remains inhomogeneous. Individual differences in neuroendocrine responsiveness, for example, cortisol responses, may be factors that explain previous inconsistent results. This study assessed the role of cortisol responsiveness in the effects of psychosocial stress on working memory. To examine working memory processes, we analyzed both behavioral performances such as accuracy, response time, the inverse efficiency score, and event-related potentials (ERPs), including N1, P2, and P3. A total of 67 male college students completed a numerical 2-back task after being exposed to the Trier Social Stress Task (TSST) or a control task. The results showed shorter response time, better efficiency, and larger N1 and P2 amplitudes in the high-cortisol-responders compared to the low-cortisol-responders and the control group. This indicates a better working memory performance likely due to the enhancements in the orientation and mobilization of attention. Furthermore, a correlation analysis revealed a positive association between the cortisol change rate and the working memory performance and ERP data among the stressed individuals, suggesting that increased cortisol may facilitate working memory under acute psychosocial stress. These findings emphasize that the individual differences in cortisol responses may affect the impact of stress on working memory.

Responding to stimuli in ambiguous environments is partially governed by approach-avoidance tendencies. Imbalances in these approach-avoidance behaviors are implicated in many mental disorders including anxiety disorders, phobias and substance use disorders. While factors biasing human behavior in approach-avoidance conflicts have been researched in numerous experiments, a much-needed comprehensive overview integrating those findings is missing. Here, we systematically searched the existing literature on individual differences in task-based approach-avoidance behavior and aggregated the current evidence for the effect of self-reported approach/avoidance traits, anxiety and anxiety disorders, specific phobias, depression, aggression, anger and psychopathy, substance use and related disorders, eating disorders and habits, trauma, acute stress and, finally, hormone levels (mainly testosterone, oxytocin). We highlight consistent findings, underrepresented research areas and unexpected results, and detail the amount of controversy between studies. We discuss potential reasons for ambiguous results in some research areas, offer practical advice for future studies and highlight potential variables such as task-related researcher decisions that may influence how interindividual differences and disorders drive automatic approach-avoidance biases in behavioral experiments.

Numerous examples of meaningful inter-individual differences in visual processing have been documented in low- and high-level vision. For mid-level vision or perceptual organization, vision scientists have only recently started to study the inter-individual differences structure. In this study, we focus on orientation and proximity as emergent features and combine a quantitative information processing approach with an individual differences approach. We first replicated the results reported in Hawkins, Houpt, Eidels, and Townsend (2016) in a set of 52 observers. That is, observers showed higher processing capacity for detecting a change in a stimulus configuration when the emergent features orientation or proximity were changed. Next, we asked whether individual differences processing capacities were similar across emergent features. The capacity to detect any type of change correlated moderately across individuals, whereas the capacity to detect changes in either emergent feature alone was not strongly correlated. This indicates that there is no general sensitivity to emergent features and that observers can be good at detecting orientation changes whilst being poor at detecting proximity changes (and vice versa). An additional exploratory multivariate analysis of the data revealed that response times and accuracies correlated strongly within each emergent feature. Moreover, specific factors related to change detection and inward displacements were observed, revealing consistent individual differences in our data. We discuss the results in the context of the literature on individual differences in vision where both specific, fragmented factors as well as broad, general factors have been reported. ispartof: Vision Research vol:169 pages:12-24 ispartof: location:England status: published

Multiple species display robust behavioral variance among individuals due to different genetic, genomic, epigenetic, neuroplasticity and environmental factors. Behavioral individuality has been extensively studied in various animal models, including rodents and other mammals. Fish, such as zebrafish (Danio rerio), have recently emerged as powerful aquatic model organisms with overt individual differences in behavioral, nociceptive and other CNS traits. Here, we evaluate individual behavioral differences in mammals and fish, emphasizing the importance of cross-species analyses of intraspecies variance in experimental models of normal and pathological CNS functions.

Background Higher neuroticism personality trait individuals have more negative mood states, more sensitive to negative information, and higher risk of mental illness. Good emotion regulation ability play an important role in healthy psychological, social and physical outcomes. Previous studies have suggested that higher neuroticism individuals have a diminished ability to regulate emotion regulation. Up to now, few studies investigate the neural basis between neuroticism and emotion regulation. Method In present study, we want to explore the neuroticism and the activity of some brain regions and functional amygdala connectivity (psycho–physiological interaction [PPI]) in a cognitive reappraisal task. Thus, 160 healthy young participants were scanned during a cognitive reappraisal task. Results The results revealed that neuroticism scores showed a significant negative association with the activity of the dorsomedial prefrontal cortex (dmPFC), inferior frontal cortex and middle frontal cortex in regulation of negative emotion. PPI analyses revealed that neuroticism scores were negatively associated with amygdala–dmPFC connectivity in regulation of negative emotion. Limitation Only cognitive reappraisal were investigated in this study. Other emotion regulation strategies such as expressive suppression need to be explored in the future study. Conclusion These results may suggest that highly neurotic participants display diminished cognitive reappraisal and diminished control function of the dmPFC over the amygdala in regulation of negative emotion.

Not all the people that consume drugs of abuse develop addiction. In this sense, just a percentage of rats express locomotor sensitization after repeated psychostimulant exposure. Neurochemical evidence has shown that locomotor sensitization is associated with changes in dorsolateral striatum (DLS) activity. However, it is unknown if individual differences observed in locomotor sensitization are related to differential neuro-adaptations in DLS activity. In this study, we measured basal dopamine (DA) levels and single unit activity in the DLS of anesthetized rats, after repeated amphetamine (AMPH) administration. Rats were treated with AMPH 1.0 mg/kg ip or saline ip for 5 days. Following 5 days of withdrawal, a challenge dose of AMPH 1.0 mg/kg ip was injected. In-vivo microdialysis experiments and single unit recording were carried out twenty-four hours after the last AMPH injection. Sensitized rats showed increased basal DA levels and baseline firing rate of medium spiny neurons (MSNs) compared to non-sensitized rats. The local variation index (Lv) was used to measure the firing pattern of MSNs. In saline rats, a bursty firing pattern was observed in MSNs. A decrease in MSNs baseline Lv accompanies the expression of AMPH locomotor sensitization. Moreover, a decrease in Lv after an acute AMPH 1.0 mg/kg injection was only observed in saline and sensitized rats. Our results show individual differences in DLS basal DA levels and firing pattern after repeated AMPH administration, suggesting that an hyperfunction of nigrostriatal pathway, accompanied by a decrease in DLS MSNs firing irregularity underlies the expression of AMPH locomotor sensitization.

Individuals differ widely in their drug-craving behaviors. One reason for these differences involves sleep. Sleep disturbances lead to an increased risk of substance use disorders and relapse in only some individuals. While animal studies have examined the impact of sleep on reward circuitry, few have addressed the role of individual differences in the effects of altered sleep. There does, however, exist a rodent model of individual differences in reward-seeking behavior: the sign/goal-tracker model of Pavlovian conditioned approach. In this model, only some rats show the key behavioral traits associated with addiction, including impulsivity and poor attentional control, making this an ideal model system to examine individually distinct sleep-reward interactions. Here, we describe how the limbic neural circuits responsible for individual differences in incentive motivation overlap with those involved in sleep-wake regulation, and how this model can elucidate the common underlying mechanisms. Consideration of individual differences in preclinical models would improve our understanding of how sleep interacts with motivational systems, and why sleep deprivation contributes to addiction in only select individuals.

In Canada, up to 3% of individuals have or are at risk of gambling disorder. Among these individuals, a lack of awareness of their problem gambling is a common barrier to treatment and negatively affects treatment adherence. A secondary analysis was conducted on data from 1346 individuals (mean age = 43.4, SD = 14.4; 54.3 % male) with problem gambling who did and did not perceive having a problem with their gambling as assessed by the fifth item of the Problem Gambling Severity Index, "In the past twelve months, how often have you felt that you might have a problem with gambling?" Additionally, we investigated predictors of increased general awareness at 12-month follow-up. At baseline, individuals who perceived a problem with their gambling experienced more gambling-related harms (OR = 1.714), had greater total gambling losses (OR = 1.067), were more likely to have a family history of problem gambling (OR = 2.143), experienced a greater loss of control (OR = 1.313) and more often gambled alone than with others (OR = 0.879), accounting for 26.6 % of the variance in general awareness. Baseline problem awareness was positively associated with attempts to cut down or control gambling at follow-up (χ

Exposure-based treatment involves repeated presentation of feared stimuli or situations in the absence of perceived threat (i.e., extinction learning). However, the stimulus or situation of fear acquisition (CS+) is highly unlikely to be replicated and presented during treatment. Thereby, stimuli that resemble the CS+ (generalization stimuli; GSs) are typically presented. Preliminary evidence suggests that depending on how one generalizes fear (i.e., different generalization rules), presenting the same GS in extinction leads to differential effectiveness of extinction learning. The current study aimed to extend this finding to safety behaviors. After differential fear and avoidance conditioning, participants exhibited discrete generalization gradients that were consistent with their reported generalization rules (Similarity vs Linear). The Linear group showed stronger safety behaviors to a selected GS compared to the Similarity group, presumably due to higher threat expectancy. After extinction learning to this GS, the Linear group exhibited stronger reduction in safety behaviors generalization compared to the Similarity group. The results show that identifying distinct generalization rules allows one to predict expectancy violation to the extinction stimulus, in addition to corroborating the idea that strongly violating threat expectancy leads to better extinction learning and its generalization. With regard to clinical implications, identifying one's generalization rule (e.g., threat beliefs) help designing exposure sessions that evoke strong expectancy violation, enhancing the reduction in the generalization of maladaptive safety behaviors.

Objectives This study aimed to investigate sleep patterns in adolescent males over a 12-week period (a 10-week school term and pre and post term holidays). Design Intensive longitudinal design, with sleep data collected daily via actigraphy for 81 consecutive days. Setting Five Secondary Schools in Adelaide, South Australia. Participants Convenience sample of 47 adolescent males aged 14 to 17 years. Measurements Daily sleep duration, bedtimes, rise times, and sleep efficiency were collected via actigraphy with all (except sleep efficiency) also measured by sleep diary. Mood was measured weekly with Depression Anxiety Stress Scale-21 (DASS-21) and weekly wellbeing with the Satisfaction with Life Scale (SWLS). Age, body mass index, self-reported mood, life satisfaction, and chronotype preference assessed at baseline (pre-term holiday week) were included as covariates. Results Dynamic Structural Equation Modeling indicated significant but small fixed-effect and random-effect auto-regressions for all sleep variables. Collectively, these findings demonstrate day-to-day fluctuations in sleep patterns, the magnitude of which varied between individuals. Age, morningness, and mood predicted some of the temporal dynamics in sleep over time but other factors (BMI, life satisfaction) were not associated with sleep dynamics. Conclusions Using intensive longitudinal data, this study demonstrated inter-individual and intra-individual variation in sleep patterns over 81 consecutive days. These findings provide important and novel insights into the nature of adolescent sleep and require further examination in future studies.

Objectives Research suggests strong associations between habitual sleep parameters (eg, mean duration, timing, efficiency), perceived stress, and insomnia symptoms. The associations between intraindividual variability (IIV; night-to-night within-person variation) in sleep, perceived stress, and insomnia have not been explored. This study examined associations between IIV in subjectively and objectively determined sleep parameters and to perceived stress in young adults with and without insomnia. Design Prospective longitudinal. Setting and participants Participants were 149 college students (mean age = 20.2 [SD = 2.4], 59% female) either with insomnia (n = 81; 54%) or without insomnia (n = 68; 46%). Measurements Participants completed 1 week of daily sleep diaries and actigraphy (to assess total sleep time [TST], sleep efficiency [SE], and circadian midpoint [CM]), the Perceived Stress Scale, and a diagnostic interview for determination of insomnia as part of a parent study. Results Greater IIV in actigraphy-determined TST (but not SE or CM) was independently associated with greater perceived stress, regardless of insomnia status. Greater IIV in sleep diary–determined TST, SE, or CM was not associated with perceived stress. Insomnia status was the most robust predictor of elevated perceived stress. There was a significant interaction between IIV in sleep diary–determined TST and insomnia status on perceived stress: Only in those without insomnia was greater IIV in sleep diary–determined TST associated with higher perceived stress. Conclusion Maintaining a more consistent sleep duration may be associated with lower stress in college students. Future research is needed to clarify the directionality and implications of this association for treatment.

Subjective well-being (SWB) is the eternal pursuit of all mankind. Individual differences in SWB may reflect the way of emotional processing. Neuroimaging studies have partly examined the neural mechanism of the individual differences in SWB using resting-state functional magnetic resonance imaging (rs-fMRI). However, few studies have investigated the relationship between the individual differences in SWB and brain functional connectivity during facial emotion processing task. Here, we applied negative facial emotion processing task-based fMRI to explore the brain functional basis of the individual differences in SWB. Results showed that SWB is positively correlated with the activation of right posterior cingulate cortex, left interior temporal gyrus and left angular gyrus for the comparison of negative stimulus and neutral stimulus, revealing that happy individuals may be more proactive to use attention transfer and behavioral inhibition strategies to decrease negative experiences during negative emotional processing. In addition, high SWB is associated with strong functional connectivity between high-level cognitive networks (e.g., frontal-parietal network) and low-level perceptual networks (e.g., sensorimotor network), and weak functional connectivity within default mode network and within low-level perceptual networks, indicating that the self-reflection, emotional regulation and cognitive control during negative facial emotion processing underlies the individual differences in SWB. These findings provide a novel insight to characterize the brain functional basis of the individual differences in SWB.

Lower estimated glomerular filtration rate (eGFR) is associated with heart failure (HF) risk. However, eGFR based on cystatin C (eGFRProspective cohort study.4,512 adults with CKD and without prevalent HF who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.Difference in GFR estimates (eGFRIncident HF hospitalization.Fine-Gray proportional subhazards regression was used to investigate the associations of baseline, time-updated, and slope of eGFROf 4,512 participants, one-third had eGFREntry into the CRIC Study was determined by eGFRAmong persons with CKD who have large differences between eGFR

Many cognitive tasks have what we refer to as a placekeeping requirement: steps or subtasks must be performed in a linear or other systematic fashion, without repetitions or omissions that would compromise performance. Here we asked whether the cognitive control mechanisms that meet this requirement are specific to individual tasks or general enough to be shared across tasks. Participants (N = 289) performed two tasks (Letterwheel and UNRAVEL) that share a sequential structure but are otherwise distinct. Placekeeping measures correlated significantly across tasks after controlling for construct-irrelevant variance, evidence that individual differences in placekeeping ability correlated across tasks rather than varying independently. Furthermore, an empirical pattern in the form of a crossover interaction in placekeeping error gradients was evident for both tasks, evidence that placekeeping in the two tasks is supported by similar cognitive mechanisms. The results suggest that placekeeping ability is a task-independent cognitive control construct and that placekeeping measures could help predict performance in a range of workplace and everyday tasks.

Previous work identified the operation of an attentional bias (AB) towards healthy food related stimuli among those with increasing tendencies towards orthorexia nervosa (ON) using a modified Stroop task. The current work aimed to replicate and extend our understanding of this effect by incorporating alternative measures of AB (i.e., the dot probe task) and ON (i.e., the Teruel Orthorexia Scale [ToS]) in a sample of self-defined vegans/vegetarians. The theoretical assertion of the ToS is the conceptual broadening of orthorexia with differentiable dimensions - one characterised as a "healthy" preoccupation with healthy food/eating patterns (HeOr) and the other by a more underlying pathology (OrNe). This study also aimed to examine the pattern of responding across these two dimensions according to factors known to predict ON. Eighty-six participants (mean age = 33.0 years; 20 males, 66 females) completed measures of obsessive compulsivity, perfectionism, state/trait anxiety and ToS as well as a dot probe designed to measure AB for healthy and unhealthy-related food stimuli, threat ratings of each of words utilized and perceived identity centrality as a vegan/vegetarianism. Results showed a dissociation of predicted determinants for "healthy" ON (HeOr) and pathological ON (OrNe). HeOr was predicted by increasing identity centrality whereas OrNe was predicted by increased OCD and perfectionism, and increased interference for healthy-related food words (in particular slowed disengagement) and not unhealthy related food words. Threat-related ratings of unhealthy food words was shown to be common across both dimensions. This pattern highlights cognitive and individual differences-based correlates of pathological and non-pathological ON.

A sense of agency (SoA) over wilful actions is thought to be dependent on the level of choice and the nature of the outcome. In a preregistered study, we manipulated choice and valence of outcome to assess the relationship between SoA across the depression and psychosis continuum. Participants (N = 151) completed a Libet Clock task, in which they had either a free or forced choice to press one of two buttons and received either a rewarding or punishing outcome. Participants also completed questionnaires on depressive and psychosis-like traits. Rewarding outcomes increased intentional binding. The evidence favoured no effect of choice on average, but this was influenced by inter-individual differences. Individuals reporting more depressive traits had less of a difference in intentional binding between free and forced choice conditions. We show that implicit SoA is sensitive to outcome valence and the effect of choice differs across the depression continuum.

Modelling and predicting individual differences in task-evoked FMRI activity can have a wide range of applications from basic to clinical neuroscience. It has been shown that models based on resting-state activity can have high predictive accuracy. Here we propose several improvements to such models. Using a sparse ensemble leaner, we show that (i) features extracted using Stochastic Probabilistic Functional Modes (sPROFUMO) outperform the previously proposed dual-regression approach, (ii) that the shape and overall intensity of individualised task activations can be modelled separately and explicitly, (iii) training the model on predicting residual differences in brain activity further boosts individualised predictions. These results hold for both surface-based analyses of the Human Connectome Project data as well as volumetric analyses of UK-biobank data. Overall, our model achieves state of the art prediction accuracy on par with the test-retest reliability of tfMRI scans, suggesting that it has potential to supplement traditional task localisers.

The ability to predict individual differences in motor learning has significant implications from both theoretical and applied perspectives. However, there is high variability in the methodological and analytical strategies employed as evidence for such predictions. Here, we critically examine the evidence for predictions of individual differences in motor learning by reviewing the literature from a 20-year period (2000-2020). Specifically, we examined four factors: (i) the predictor and predicted variables used, (ii) the strength of the prediction and associated sample size, (iii) the timescale over which the prediction was made, and (iv) the type of motor task used. Overall, the results highlight several issues that raise concerns about the quality of the evidence for such predictions. First, there was a large variation in both predictor and predicted variables, suggesting the presence of a large number of researcher degrees of freedom. Second, sample sizes tended to be small and the strength of the correlation showed an inverse relation with sample size. Third, the timescale of most predictions was very short, mostly constrained to a single day. Last, most studies were largely restricted to two experimental paradigms - adaptation and sequence learning. Based on these issues, we highlight recommendations for future studies to improve the quality of evidence for predicting individual differences in motor learning.

Racism and intergroup discrimination are pervasive problems in human societies. Whereas several studies have shown that children show bias in the context of many kinds of groups, much less is known about how and when general psychological tendencies and contextual factors contribute to the manifestation of intergroup bias across development, and whether individual differences play a role. In the present study, we pursue these questions by investigating and comparing the developmental trajectories of intergroup bias in 5- to 10-year-old (mostly) White children (n = 100). We assessed children's liking and preferences towards 4 racial groups (White, East Asian, Black, and Middle Eastern) and towards 2 gender groups (male and female) in a within-subject design. We found that the young children in our sample showed a significant racial and gender ingroup bias, speaking to an early and strong manifestation of intergroup bias on the basic ingroup-outgroup distinction. This bias decreased with age. At the same time, we found considerable differences between the different types of outgroups from early on. Furthermore, there were remarkable differences between the developmental trajectories of gender and racial intergroup bias, highlighting the role of both social and contextual influences. Finally, our results did not reveal consistent evidence for the influence of individual differences on children's intergroup bias.

Objective we examined individual differences in the effects of expressive writing. We hypothesized that moderate levels of neuroticism, low levels of experiential avoidance, and highly rated subjective severity would be linked to greater change in well-being post-writing. Design participants were randomly assigned to the expressive group (N = 104) who wrote about emotion-laden experiences, or the control group (N = 51) who wrote about everyday events. All completed the IES and BSI pre and 1, 3, and 6 weeks post-writing. Results overall, we replicated the seminal result, with greater reductions in IES scores in the expressive writing group. In addition, in the expressive group, as expected, participants with higher severity scores had greater reductions in BSI scores. Surprisingly, individuals with high rather than moderate neuroticism and high rather than low experiential avoidance scores also experienced more benefit. Conclusions participants who are more aware of, in touch with, and suffer more from negative feelings are those who gain the most from expressive writing. Based on this conclusion, clinical implications relevant to both psychotherapy patients and non-patients are suggested.

Novel approaches to address cognitive aging and to delay or prevent cognitive decline in older individuals will require a better understanding of the biological and environmental factors that contribute to it. Studies in animal models—in particular, animals whose cognitive trajectory across their life span closely tracks that of humans—can provide important insights into the factors that contribute to the accumulation of reserve and ways in which it is preserved or depleted. A better understanding of the molecular processes that underlie these elements would enhance and guide not only research but also treatment approaches to these issues. These treatment approaches may include noninvasive brain stimulation and drug treatments to promote youthfulness or combat the aging process. It is important to realize, however, that these processes occur in the context of the human experience, and studies of them must consider the complexity and individuality of each person’s life.

Background In the biopsychosocial formulation of functional neurological (conversion) disorder (FND), little is known about relationships between social behavior and brain anatomy. We hypothesized that social behavior would relate to brain areas implicated in affiliative behaviors and that social network size would correlate with symptom severity and predisposing vulnerabilities in FND. Methods This neuroimaging pilot probed how social network size, as measured by the Social Network Index, related to structural brain profiles in 23 patients with motor FND (15 woman and 8 men). FreeSurfer cortical thickness and subcortical volumetric analyses were performed correcting for multiple comparisons. Stratified analyses compared FND patients with a low social network size to matched healthy controls. Secondary exploratory analyses in an expanded sample of 38 FND patients investigated relationships between social network size, risk factors and patient-reported symptom severity. Results Adjusting for age and gender, neuroimaging analyses showed that social network size positively correlated with left nucleus accumbens and hippocampal volumes in patients with FND; stratified analyses did not show any group-level differences. In individuals with FND, social network size correlated with health-related quality of life, graduating college, working full-time and a non-epileptic seizure diagnosis; social network size inversely related to lifetime trauma burden, post-traumatic stress disorder severity and age. Limitations Only patient-reported scales were used and social network size information was not collected for healthy subjects. Conclusions This neuroimaging pilot adds to the literature linking affiliation network brain areas to pro-social behaviors and enhances the biopsychosocial conceptualization of FND.

The competitive and inhibitory interactions between the two eyes’ images are a pervasive aspect of binocular vision. Over the last decade, our understanding of the neural processes underpinning binocular rivalry (BR) and continuous flash suppression (CFS) has increased substantially, but we still have little understanding of the relationship between these two effects and their variation in the general population. Studies that pool data across individuals and eyes risk masking substantial variations in binocular vision that exist in the general population. To investigate this issue we compared the depth of inter-ocular suppression evoked by BR with that elicited by CFS, in a group (N = 25) of visually normal individuals. A noise pattern (either static for BR or dynamic for CFS) was presented to one eye and its suppressive influence on a probe grating presented simultaneously to the other eye was measured. We found substantial individual differences in the magnitude of suppression (a 10-fold variation in probe detection threshold) evoked by each task, but performance on BR was a significant predictor of performance on the CFS task. However many individuals showed marked asymmetries between the two eyes’ ability to detect a suppressed target, that were not necessarily the same for the two tasks. There was a tendency for the magnitude of the asymmetry to increase as the refresh rate of the dynamic noise increased. The results suggest a common underlying mechanism is likely to be responsible, at least in part, for driving inter-ocular suppression under BR and CFS. The marked asymmetries in inter-ocular suppression at higher noise refresh rates, may be indicative of a difference in temporal processing between the eyes.

Misalignment of circadian timing in patients with depression has commonly been reported, but the underlying mechanisms are not known. Individual differences in the sensitivity of the circadian system to light affect how the biological clock synchronizes with the external environment and can lead to misalignment of rhythms. We investigated the sensitivity of the circadian system to light in unmedicated (for3 months) women with a current or previous diagnosis of major depression, and healthy controls.Baseline melatonin levels in dim light (1 lux) were assessed, followed by melatonin levels in normal indoor lighting of 100 lux in order to determine melatonin suppression.Patients currently experiencing a depressive episode showed significantly lower levels of melatonin suppression to light compared to remitted patients and controls, with large effect sizes. Remitted patients and controls showed similar suppression.The relatively small sample, and lack of long-term, within subject assessments, make it difficult to determine the potential causal role of reduced light sensitivity in the development of circadian disruption.We conclude that hyposensitivity of the circadian system to light may contribute to circadian misalignment in patients with depression. Interventions that increase sensitivity to light or provide stronger light cues may assist in normalizing circadian clock function.