Widespread associations between trait conscientiousness and thickness of brain cortical regions

The neural correlates of human personality have been of longstanding interest; however, most studies in the field have relied on modest sample sizes and few replicable results have been reported to date. We investigated relationships between personality and brain gray matter in a sample of generally healthy, older (mean age 73 years) adults from Scotland drawn from the Lothian Birth Cohort 1936. Participants (N = 578) completed a brain MRI scan and self-reported Big Five personality trait measures. Conscientiousness trait scores were positively related to brain cortical thickness in a range of regions, including bilateral parahippocampal gyrus, bilateral fusiform gyrus, left cingulate gyrus, right medial orbitofrontal cortex, and left dorsomedial prefrontal cortex. These associations – most notably in frontal regions – were modestly-to-moderately attenuated by the inclusion of biomarker variables assessing allostatic load and smoking status. None of the other personality traits showed robust associations with brain cortical thickness, nor did we observe any personality trait associations with cortical surface area and gray matter volume. These findings indicate that brain cortical thickness is associated with conscientiousness, perhaps partly accounted for by allostatic load and smoking status

Trait Conscientiousness and the Personality Meta-Trait Stability are Associated with Regional White Matter Microstructure

Establishing the neural bases of individual differences in personality has been an enduring topic of interest. However, while a growing literature has sought to characterize grey matter correlates of personality traits, little attention to date has been focused on regional white matter correlates of personality, especially for the personality traits agreeableness, conscientiousness and openness. To rectify this gap in knowledge we used a large sample (n > 550) of older adults who provided data on both personality (International Personality Item Pool) and white matter tract-specific fractional anisotropy (FA) from diffusion tensor MRI. Results indicated that conscientiousness was associated with greater FA in the left uncinate fasciculus (β = 0.17, P < 0.001). We also examined links between FA and the personality meta-trait ‘stability’, which is defined as the common variance underlying agreeableness, conscientiousness, and neuroticism/emotional stability. We observed an association between left uncinate fasciculus FA and stability (β = 0.27, P < 0.001), which fully accounted for the link between left uncinate fasciculus FA and conscientiousness. In sum, these results provide novel evidence for links between regional white matter microstructure and key traits of human personality, specifically conscientiousness and the meta-trait, stability. Future research is recommended to replicate and address the causal directions of these associations

Cognitive alterations in Multiple Sclerosis patients: diagnostic, prognostic, and rehabilitation aspects

Cognitive impairment is frequent in most patients with Multiple Sclerosis (MS) and affects several cognitive domains, having a significant impact on their quality of life and on their personal, social and work dimensions. An early and comprehensive neuropsychological assessment may provide relevant diagnostic, prognostic, and rehabilitative implications. The first chapter highlights the diagnostic and the prognostic aspects, with the description of a multicentric project, conducted in collaboration with MS centers of Bergamo, Montichiari, and Modena, in which were included newly-diagnosed MS patients and were evaluated their neurological, neuropsychological, neuroradiological and bioumoral outcomes. Results of this project have allowed the preparation of several sub-studies with important results: the first study highlighted how MS patients at the time of diagnosis, even in the absence of an evident cognitive impairment as clinically defined, are characterized by slight cognitive alterations as compared to healthy controls, both considering global cognitive functioning level and also specific cognitive domains. The second study has allowed the identification of two biomarkers present in the cerebrospinal fluid that are associated with cognitive alterations: the first (LIGHT) is associated with the inflammatory phase of the disease, while the second (parvalbumin) is associated with the neurodegenerative phase of the disease and also correlates with cortical thinning and physical disability, moreover with a stronger association compared to the one found with the level of neurofilament light chain (NF-L, a well-known biomarker of neurodegeneration). The third study has allowed to describe the predictive role of some inflammatory cytokines in the cerebrospinal fluid (CXCL13, CXCL12, IFNγ, TNF, TWEAK, LIGHT, sCD163) in discriminating, since the time of diagnosis, those MS patients that were more likely to develop neurologic and neuroradiologic worsening after 4-years follow-up. The second chapter addresses the importance of assessing MS patients not only with the classical neuropsychological tests but also with experimental paradigms. The first study, conducted in collaboration with the University of Florence and the University of Padua, investigated the phenomena of false memories, using a paradigm that induces memory distortions due to the strong connection between words associated with a same semantic category. Results showed that MS patients were not characterized by the expected memory distortions, probably due to weak association between nodes that compose semantic memory, because of neurodegenerative events. The second study, conducted in collaboration with the Kessler Foundation (West Orange, NJ, USA), focused on social cognition abilities: in a group of MS patients without evidence of cognitive impairment as traditionally defined was observed a performance significantly lower compared to healthy controls in tests of facial emotion recognition, theory of mind, and empathy. Moreover, it was demonstrated that these social cognition alterations were correlated specifically with the cortical lesions volume in both the amygdalae of MS patients, while no significant correlation was found with other measures of brain damage included in the study (cortical thickness and cortical lesion load in all the cerebral cortex). The third and last chapter focuses on the rehabilitative aspects, showing results from a study carried at the Buffalo Neuroimaging Analysis Center (Buffalo, NY, USA) on a group of MS patients that performed a cognitive training by using a telerehabilitation approach. The project aimed to identify neurological, psychological and neuroradiological variables able to characterize patients that can benefit more from the rehabilitation. Results showed that a relapsing-remitting disease phenotype (as compared with progressive patients), a higher personality trait of conscientiousness, a higher gray matter volume, a lower tract disruption in a network centered on precuneus and posterior cingulate, and a higher deviation in functional brain connectivity compared to healthy controls, play a key role to achieve a greater cognitive amelioration after the rehabilitative treatment

Online Betting Intensity is Linked with Extraversion and Conscientiousness

Introduction Extraversion and Conscientiousness are well-studied personality traits associated with reward processing and goal prioritization, respectively, and bear on individual differences in financial risk-taking. Using unique large datasets, we investigated the link between these traits and male online gamblers' actual betting participation and intensity. Method We combined datasets containing online horse betting data (during 2015-2016) from the Finnish monopoly betting company, administrative registry data from Statistics Finland, and personality trait measures from the Finnish Defence Forces corresponding to Extraversion and Conscientiousness as defined in the five-factor model. We modelled associations between these traits and betting participation (n = 471,968) and intensity (n = 11,217) among male horse bettors (age = 36-53). Results Controlling for demographics and IQ, individuals scoring high on Conscientiousness (or Extraversion) were less (or more) likely to bet and less (or more) intensive bettors-even when personality was measured 16-34 years before betting occurred. One SD personality score increase represented an annual decrease (Conscientiousness) or increase (Extraversion) of euro570-754 in spending. Conclusions Extraversion and Conscientiousness are implicated in real-life financial behavior with tangible consequences for individuals. These effects are stronger than for many known demographic variables used in gambling studies and persist up to 34 years after personality has been measured.Peer reviewe

Association of big-5 personality traits with cognitive impairment and dementia: a longitudinal study

BACKGROUND: Personality traits have been linked to cognitive outcomes such as dementia, but whether these associations are robust to the effects of third variables remains the subject of debate. We examined the role of socioeconomic status, depression (history and depressive symptoms), health behaviours and chronic conditions in the association of the big-5 personality traits with cognitive performance, cognitive impairment and incidence of dementia. METHODS: Data on 6135 persons (30% women), aged 60-83 years in 2012/13, are drawn from the Whitehall II Study. Participants responded to the 26-item Midlife Development Inventory to assess personality traits (openness, conscientiousness, extraversion, agreeableness and neuroticism), underwent cognitive testing in 2012/13 and 2015/16 and were followed for incidence of dementia (N=231) until 2019. RESULTS: Logistic regression, adjusted for sociodemographic factors, suggested a cross-sectional association with cognitive impairment for four of the five traits but only neuroticism was associated with incident cognitive impairment. All associations were completely attenuated when the analyses were adjusted for depression. Cox regression (mean follow-up: 6.18 years) adjusted for sociodemographic variables showed higher conscientiousness (HR per SD increment=0.72; 95% CI 0.65 to 0.81) and extraversion (HR=0.85; 95% CI 0.75 to 0.97) to be associated with lower dementia risk; higher neuroticism (HR=1.32; 95% CI 1.17 to 1.49) was associated with increased risk. Further adjustment for depression led to only conscientiousness retaining an association with dementia (HR=0.81; 95% CI 0.69 to 0.96), which was robust to adjustment for all covariates (HR=0.84; 95% CI 0.71 to 0.91; P=0.001). CONCLUSION: Our results show that only conscientiousness has an association with incidence of dementia that is not attributable to socioeconomic status or depression. The association of neuroticism with dementia was explained by depression

Distinctive Frontal and Occipitotemporal Surface Features in Neglectful Parenting.

Although the brain signatures of adaptive human parenting are well documented, the cortical features associated with maladaptive caregiving are underexplored. We investigated whether cortical thickness and surface area vary in a small group of mothers who had neglected their children (24 in the neglect group, NG) compared to a control group of mothers with non-neglectful caregiving (21 in the control group, CG). We also tested whether the cortical differences were related to dyadic mother-child emotional availability (EA) in a play task with their children and whether alexithymia involving low emotional awareness that characterizes the NG could play a role in the cortical-EA associations. Whole-brain analysis of the cortical mantle identified reduced cortical thickness in the right rostral middle frontal gyrus and an increased surface area in the right lingual and lateral occipital cortices for the NG with respect to the CG. Follow-up path analysis showed direct effects of the right rostral middle frontal gyrus (RMFG) on the emotional availability (EA) and on the difficulty to identify feelings (alexithymia factor), with a marginal indirect RMFG-EA effect through this factor. These preliminary findings extend existing work by implicating differences in cortical features associated with neglectful parenting and relevant to mother-child interactive bonding

Individual Differences In Value-Based Decision-Making: Learning And Time Preference

Human decisions are strongly influenced by past experience or by the subjective values attributed to available choice options. Although decision processes show some common trends across individuals, they also vary considerably between individuals. The research presented in this dissertation focuses on two domains of decision-making, related to learning and time preference, and examines factors that explain decision-making differences between individuals. First, we focus on a form of reinforcement learning in a dynamic environment. Across three experiments, we investigated whether individual differences in learning were associated with differences in cognitive abilities, personality, and age. Participants made sequential predictions about an on-screen location in a video game. Consistent with previous work, participants showed high variability in their ability to implement normative strategies related to surprise and uncertainty. We found that higher cognitive ability, but not personality, was associated with stronger reliance on the normative factors that should govern learning. Furthermore, learning in older adults (age 60+) was less influenced by uncertainty, but also less influenced by reward, a non-normative factor that has substantial effects on learning across the lifespan. Second, we focus on delay discounting, the tendency to prefer smaller rewards delivered soon over larger rewards delivered after a delay. Delay discounting has been used as a behavioral measure of impulsivity and is associated with many undesirable real-life outcomes. Specifically, we examined how neuroanatomy is associated with individual differences in delay discounting in a large adolescent sample. Using a novel multivariate method, we identified networks where cortical thickness varied consistently across individuals and brain regions. Cortical thickness in several of these networks, including regions such as ventromedial prefrontal cortex, orbitofrontal cortex, and temporal pole, was negatively associated with delay discounting. Furthermore, this brain data predicted differences beyond those typically accounted for by other cognitive variables related to delay discounting. These results suggest that cortical thickness may be a useful brain phenotype of delay discounting and carry unique information about impulsivity. Collectively, this research furthers our understanding of how cognitive abilities, brain structure and healthy aging relate to individual differences in value-based decision-making

Distinctive Frontal and Occipitotemporal Surface Features in Neglectful Parenting

Published: 18 March 2021Although the brain signatures of adaptive human parenting are well documented, the cortical features associated with maladaptive caregiving are underexplored. We investigated whether cortical thickness and surface area vary in a small group of mothers who had neglected their children (24 in the neglect group, NG) compared to a control group of mothers with non-neglectful caregiving (21 in the control group, CG). We also tested whether the cortical differences were related to dyadic mother-child emotional availability (EA) in a play task with their children and whether alexithymia involving low emotional awareness that characterizes the NG could play a role in the cortical-EA associations. Whole-brain analysis of the cortical mantle identified reduced cortical thickness in the right rostral middle frontal gyrus and an increased surface area in the right lingual and lateral occipital cortices for the NG with respect to the CG. Follow-up path analysis showed direct effects of the right rostral middle frontal gyrus (RMFG) on the emotional availability (EA) and on the difficulty to identify feelings (alexithymia factor), with a marginal indirect RMFG-EA effect through this factor. These preliminary findings extend existing work by implicating differences in cortical features associated with neglectful parenting and relevant to mother-child interactive bonding.This research was funded by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund, grant number RTI2018‐098149‐B‐I00 to M.J.R. and I.L, and by the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska‐Curie Individual Fellowship, grant agreement number 893329 to L.G.P

Relationships between Personality Traits, Medial Temporal Lobe Atrophy, and White Matter Lesion in Subjects Suffering from Mild Cognitive Impairment

Mild cognitive impairment (MCI) is a heterogeneous cognitive status that can be a prodromal stage of Alzheimer’s disease (AD). It is particularly relevant to focus on prodromal stages of AD such as MCI, because patho-physiological abnormalities of AD start years before the dementia stage. Medial temporal lobe (MTL) atrophy resulting from AD lesions and cerebrovascular lesions [i.e., white matter lesions (WML), lacunar strokes, and strokes] are often revealed concurrently on magnetic resonance imaging (MRI) in MCI subjects. Personality changes have been reported to be associated with MCI status and early AD. More specifically, an increase in neuroticism and a decrease in conscientiousness have been reported, suggesting that higher and lower scores, respectively, in neuroticism and conscientiousness are associated with an increased risk of developing the disease. However, personality changes have not been studied concomitantly with pathological structural brain alterations detected on MRI in patients suffering from MCI. Therefore, the objective of the present study was to assess the relationship between MTL atrophy, WML, lacunar strokes, and personality traits in such patients. The severity of WML was strongly associated with lower levels of conscientiousness and higher levels of neuroticism. Conversely, no association was detected between personality traits and the presence of lacunar strokes or MTL atrophy. Altogether, these results strongly suggest that personality changes occurring in a MCI population, at high risk of AD, are associated with WML, which can induce executive dysfunctions, rather than with MTL atrophy