Problem 4: Personality and the Brain Flashcards
Neurotransmitters
= biochemical substances involved in the communication among nerve cells, or neurons
–> can act in such a ways as to speed up the communication of messages from one neuron to the next, or to slow down that communication
–> the “firing” of neurons is the basis of our emotions, our thoughts, and our behaviors
Dopamine
Facilitates response to pleasurable, exciting stimuli
–> associated with Extraversion and Openness
–> involved in motivation, emotion, and reward
–> involved in higher cognition (PFC)
Serotonin
Inhibits response to harmful, unpleasant stimuli
–> associated with Neuroticism, Agreeableness, or Conscientiousness
–> low levels: aggression, poor impulse control, and depression
Norepinephrine
Inhibits response to stimuli that have previously been associated with pleasure –> inhibits signals of conditioned reward
Tridimensional Personality Model - Cloninger
Dopamine and Novelty Seeking
Individuals whose dopamine system is very active will tend to have high levels of “Novelty Seeking”
–> the tendency to seek pleasure and excitement
Individuals whose dopamine system is very inactive will den to be low in Novelty Seeking
–> they will not be particularly motivated to find fun and variety
Tridimensional Personality Model - Cloninger
Serotonin and Harm Avoidance
Individuals whose serotonin system is very inactive will tend to have high levels of “Harm Avoidance”
–> the tendency to avoid pain and anxiety
Individuals whose serotonin system is very active will tend to be low in Harm Avoidance
–> they will not be particularly motivated to avoid pain and anxiety
Tridimensional Personality Model - Cloninger
Norepinephrine and Reward Dependence
Individuals whose norepinephrine system is very inactive tend to have high levels of “Reward Dependence”
–> the tendency to develop strong sentimental attachments
Individuals whose norepinephrine system is very active will tend to be low in Reward Dependence
–> they will tend not to develop strong sentimental attachments
Reinforcement Sensitivity Theory - Gray
Behavioral Activation System (BAS)
= regions from the brain that are responsible for receiving signals from the nervous system which indicate that rewards are being experienced (or are about to be experienced)
–> “go” system - encourages the pursuit of rewards, by transmitting signals within the brain to communicate the pleasurable and exciting nature of those rewards
–> similar to Cloninger’s Novelty Seeking
Reinforcement Sensitivity Theory - Gray
Behavioral Inhibition System (BIS)
= regions of the brain that are responsible for receiving signals from the nervous system which indicate that punishments are being experienced (or may soon be experienced)
–> “stop” system - encourages the avoidance of punishments, by transmitting signals within the brain to communicate the painful and frightening nature of those punishments
–> similar to Cloninger’s Harm Avoidance
Reinforcement Sensitivity Theory - Gray
Fight-or-Flight System
= regions of the brain that are responsible for motivating extreme reactions - fighting and/or fleeing - in response to extremely threatening situations
Theory of Personality - Eysenck
Extraversion
= strength of people’s reactions to stimulation of their senses –> arousability of their brains
–> very extraverted people tend to seek stimulation, and therefore enjoy bright colors, loud noises, other sensations, and meeting and interacting with lots of people
–> very introverted people tend to avoid stimulation, quieter surroundings, and prefer to be alone or with a few others
Ascending reticular activation system (ARAS):
- a filter that regulates the amount of stimulation that is admitted to the brain from the nervous system, which receives stimulation from the environment
- little stimulation: under-aroused, stimulation-seeking, extraverted personality
- great stimulation: over aroused, stimulation-avoiding, introverted personality
–> related to Gray’s Behavioral Activation System
Theory of Personality - Eysenck
Neuroticism
= the strength of people’s reactions to stressful stimuli
–> very neurotic people feel a great deal of worry and nervousness in response to life’s problems
–> emotionally stable people feel little of the negative emotions that are caused by life’s distresses
Limbic System:
- regulate responses to stress
- overwhelmed by stressors: neurotic personality
- handle stressors: stable personality
–> related to Gray’s Behavioral Inhibition System
Theory of Personality - Eysenck
Psychoticism
= traits such as aggressiveness, manipulation, tough-mindedness, risk-taking, irresponsibility, and impulsivity versus their opposites
–> high levels of Psychoticism were associated with criminal behavior, various mental illnesses, and creativity
–> persons high in Psychoticism tended to have high levels of the hormone testosterone and low levels of monoamine oxidase (MOA)
Zuckerman’s Model
Five factors are believed to represent the basic dimensions of personality/temperament:
Activity
Sociability
Impulsive Sensation-Seeking
Aggression
Neuroticism- Anxiety
–> each of the personality dimensions is caused by its own set of complex interactions among brain structures, neurotransmitters, and hormones, and not by a single one of these
Testosterone
= a hormone that is responsible for many of the physical characteristics of men
–> testosterone levels can be influenced by events: competitive situations; increase after victory
–> higher levels of testosterone: wilder, more unruly, more rambunctious, more violent crimes
–> women do naturally have some testosterone, but men’s levels are typically at least 10 x higher
–> triggers the development of male reproductive sex organs and male secondary sex organs
Cortisol
= a hormone that is released by the adrenal cortex in response to physical or psychological stress
–> function: prepare the body for action in response to stress - increase in blood pressure, blood sugar, and suppression of the immune system
–> cortisol levels might be an indicator (at least in boys) of overall emotional reactivity
–> little cortisol release: emotionally insensitive
Oxytocin
= a hormone that is produced in the hypothalamus and released by the pituitary gland
–> in women, released when giving birth, breastfeeding, having an orgasm
–> associated with emotional bonding: establishing attachments between persons, cooperative relationships, facilitates tendencies to be trusting and trustworthy
Oxytocin administration
Exogenous administration of synthetic OXT includes subtle changes in social behaviors
–> tendencies toward increased sociality, including trust, empathy, approach, and altruism
–> targets reward-related and fear-related neurocircuits
–> potential treatment for psychiatric conditions ranging from anxiety to autism spectrum disorders
–> the effects of OXT on prosocial behavior are highly susceptible due to individual and contextual variables
–> OXT may interact with other hormonal and neurotransmitter systems
–> interacts with person-specific factors related to trust and affiliation
Intranasal OXT administration
= the most direct and non-invasive way to assay the central actions of OXT in humans
–> bypasses the blood-brain barrier (BBB)
OXT-system and prosocial behavior
prosocial = a wide range of positive social behaviors, including trust, cooperation, care, empathy, and altruism - all of which are mainstays of forming and maintaining adaptive human social relationships
altruism = non-reciprocal prosocial acts which are aimed at improving the welfare of another individual at a personal cost to the altruist
–> the OXT-system is involved in both the formation and maintenance of social relationships, in part through its central involvement in orchestrating altruism and associated prosocial behaviors
–> effects are mediated by the amygdala, the anterior insula, and the anterior cingulate cortex
Oxytocin and therapeutic potential
Oxytocin enhances social salience rather than social behavior, and for oxytocin administration to be therapeutic and influence behavior, it must be paired with an appropriate social context.
–> oxytocin changes the way in which incoming social stimuli are perceived and processed, which can influence behavior and social learning in various ways
–> oxytocin is a powerful neuromodulator: it makes the brain more attentive to social stimuli, promotes synaptic plasticity, and facilitates social learning by modulating neural circuits
–> oxytocin should be used as a tool to prime the brain for receiving, processing, and learning social information during cognitive and behavioral therapy interventions
–> future clinical studies must explore the potential of pairing oxytocin with therapeutic contexts
Personality Neuroscience
= the use of neuroscience methods to study individual differences in behavior, emotion, and cognition
aim: understand both the biological systems that are responsible for the states associated with traits and the parameters of those systems that cause them to function differently in different individuals
The structure of personality traits
- Hierarchical arrangement - correlated groups of
more specific traits are categorized together - Metatraits (higher-order factor structure)
- Stability: shared variance of Neuroticism,
Agreeableness, and Conscientiousness - Plasticity: shared variance of Extraversion and
Openness
- Stability: shared variance of Neuroticism,
- Facets - shared variance of lower-level traits
- Aspects - two separable but correlated aspects
of which each Big Five factor is comprised
Meta-traits
Stability represents a general tendency to regulate or restrain potentially disruptive emotion and behavior
–> related to serotonin
Plasticity represents a general tendency to explore and engage with possibilities
–> related to dopamine
Trait Theory
- Trait theory views traits as orthogonal and
dimensional constructs that allow for each
individual to be positioned in a multidimensional
trait space - A person scoring at the upper end of a given
trait will respond consistently stronger to
relevant stimuli than a person with lower scores
on the respective trait - Trait theory posits that these neural substrates
are characterized by the same trait-like
properties as behavioral traits such as
invariance across situations and time - Each situation is characterized by a unique
brain state consisting of (a) a neural reaction
elicited by the physical aspect of the stimulus
and (b) an idiosyncratic component associated
with the individual trait level
Psychometrics
= a psychological discipline focused on theories and techniques to measure psychological constructs
internal consistency: a technical term from psychometrics that reflects how reliable an instrument measures a psychological construct
Personality Network Neuroscience (PNN)
The goal of PNN is to identify and integrate neural systems (or biophysical entities) associated with psychological trait conceptions within an integrated framework for human personality
