Fractional anisotropyFractional anisotropy (FA) is a scalar value between zero and one that describes the degree of anisotropy of a diffusion process. A value of zero means that diffusion is isotropic, i.e. it is unrestricted (or equally restricted) in all directions. A value of one means that diffusion occurs only along one axis and is fully restricted along all other directions. FA is a measure often used in diffusion imaging where it is thought to reflect fiber density, axonal diameter, and myelination in white matter.
Personality typeIn psychology, personality type refers to the psychological classification of different types of individuals. Personality types are sometimes distinguished from personality traits, with the latter embodying a smaller grouping of behavioral tendencies. Types are sometimes said to involve qualitative differences between people, whereas traits might be construed as quantitative differences. According to type theories, for example, introverts and extraverts are two fundamentally different categories of people.
CorrelationIn statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics it usually refers to the degree to which a pair of variables are linearly related. Familiar examples of dependent phenomena include the correlation between the height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the so-called demand curve.
ConscientiousnessConscientiousness is the personality trait of being careful or diligent. Conscientiousness implies a desire to do a task well, and to take obligations to others seriously. Conscientious people tend to be efficient and organized as opposed to easy-going and disorderly. They tend to show self-discipline, act dutifully, and aim for achievement; they display planned rather than spontaneous behavior; and they are generally dependable.
Factor analysisFactor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially lower number of unobserved variables called factors. For example, it is possible that variations in six observed variables mainly reflect the variations in two unobserved (underlying) variables. Factor analysis searches for such joint variations in response to unobserved latent variables.
Dependent personality disorderDependent personality disorder (DPD) is characterized by a pervasive psychological dependence on other people. This personality disorder is a long-term condition in which people depend on others to meet their emotional and physical needs, with only a minority achieving normal levels of independence. Dependent personality disorder is a cluster C personality disorder, which is characterized by excessive fear and anxiety. It begins prior to early adulthood, and it is present in a variety of contexts and is associated with inadequate functioning.
Alternative five model of personalityThe alternative five model of personality is based on the claim that the structure of human personality traits is best explained by five broad factors called impulsive sensation seeking (ImpSS), neuroticism–anxiety (N-Anx), aggression–hostility (Agg-Host), sociability (Sy), and activity (Act). The model was developed by Marvin Zuckerman and colleagues as a rival to the well-known five factor model of personality traits and is based on the assumption that "basic" personality traits are those with a strong biological-evolutionary basis.
ThalamusThe thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, allowing hub-like exchanges of information. It has several functions, such as the relaying of sensory signals, including motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness.
Diffusion MRIDiffusion-weighted magnetic resonance imaging (DWI or DW-MRI) is the use of specific MRI sequences as well as software that generates images from the resulting data that uses the diffusion of water molecules to generate contrast in MR images. It allows the mapping of the diffusion process of molecules, mainly water, in biological tissues, in vivo and non-invasively. Molecular diffusion in tissues is not random, but reflects interactions with many obstacles, such as macromolecules, fibers, and membranes.
Harm avoidanceHarm avoidance (HA) is a personality trait characterized by excessive worrying; pessimism; shyness; and being fearful, doubtful, and easily fatigued. In MRI studies HA was correlated with reduced grey matter volume in the orbito-frontal, occipital and parietal regions. Harm avoidance is a temperament assessed in the Temperament and Character Inventory (TCI), its revised version (TCI-R) and the Tridimensional Personality Questionnaire (TPQ) and is positively related to the trait neuroticism and inversely to extraversion in the Revised NEO Personality Inventory and the Eysenck Personality Questionnaire.
