Chapter 8 - The Anatomy and Physiology of Personality Flashcards
What two aspects of the brain are examined by technology?
- anatomy - looks at the functions of the brain
- biochemistry - effects of neurotransmitters and hormones
- both are related to personality
What are the two main parts of nerves (involving communication)?
- axons
- dendrites
What are the two kinds of nerves?
- afferent nerves: go from the body to the brain
2. efferent nerves: go from the brain to the body
What are some research methods for examining the anatomical foundations of personality?
- through case studies (like Phineas Gage)
- observation or manipulation of lesions to pinpoint deficits
- brain stimulation (in animals and people)
- Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are both used to create virtual lesions (allows us to see what brain areas are responsible for personality)
- brain activity and imaging
- used to observe direct functioning
- used to detect WHEN the brain is working using techniques like EEG and MEG, which tell us if the brain is active, but not at what areas
- used to detect WHAT is active using
- used to observe direct functioning
What happened in a case study of a woman suffering from parkinson’s when they used brain stimulation in an attempt to alleviate her symptoms?
- they stimulated the substantia nigra (near the amygdala)
- upon stimulation, depressive symptoms set in (quickly)
- return to normal when area was not stimulated
How can we use brain imaging to observe the anatomical aspects of personality?
- used to detect WHEN the brain is working using techniques like EEG and MEG, which tell us if the brain is active, but not at what areas
- used to detect WHAT is active using techniques like CT scans (x-ray for brain), PET scan (examines blood flow), fMRI (blood oxygenation level - BOLD signal)
What are the difficulties with brain imaging techniques?
- may actually indicate inhibitory activity
- the whole brain is active to some extent at all times
- blood oxygenation level dependent - comparisons among people could be faulty or misinterpreted
- brain activity in response to a stimulus does not mean the same physiological processes occurs every time that the area is active (ex. emotions)
- we can’t neatly separate specific functions to specific brain regions
What is the primary function of the amygdala?
- it links perceptions and thoughts with emotional meaning (role in both positive and negative emotions)
What are some other roles of the amygdala?
- role in assessing whether a stimulus is threatening or rewarding
- relevant for motivation (ex. Whitman murders at University of Texas in 1966 - tumour in the basal ganglia was found, which is located near the amygdala…thoughts were unpaired with emotions)
What happens if thoughts, or emotions, are distorted?
if thoughts are distorted, emotions will be too, and vice versa
What are the frontal lobe and neocortex mainly responsible for?
higher cognitive functions
What are other functions of the frontal lobe and neocortex?
- pleasant emotions (left side) and unpleasant emotions (right side)
- inhibition of reactions to unpleasant stimuli (left side)
- emotional stability (left)
- neuroticism (right)
- personality activates the frontal lobe
What do Phineas Gage and Elliott have in common?
they had similar brain damage and therefore experiences similar personality shifts
- both became unemotional and had difficulty making decisions (couldn’t attach thoughts to feelings)
what is the somatic marker hypothesis?
using emotional reactions/experiences for decision making
Describe Capgras syndrome?
- follows injury to right frontal lobe
- the person believes their loved ones have been replaced with strangers impersonating their friends and family
- possibly due to a failure to respond emotionally when the injured person saw their loved one (therefore their thoughts were impacted)
What two methods of psychosurgery impacted personality?
- prefrontal leucotomy: damaged small regions of frontal lobe (first psychosurgery)
- prefrontal lobotomy: removing whole sections of the frontal lobe
What were the observations of the psychosurgeries consistent with?
- types of brain damage already observed
- psychosurgery replaced with drugs
What is the method of communication that neurons use?
Neurotransmitters
What do hormones do?
stimulate or inhibit neural activity
About how many chemicals transmit information in the brain?
60
- people differ in average levels
What is the primary role of dopamine?
reward system of the brain; approaching attractive objects and people
What are dopamine’s other responsibilities?
related to sociability and activity level
What disease is marked by a lack of dopamine?
Parkinson’s
What fundamental dimension of personality is dopamine related to?
plasticity: combination of extraversion and openness to experience
What is the primary role of serotonin?
inhibits behavioural impulses
What are some other roles of serotonin in the brain?
helps to avoid excessive worrying and being oversensitive
Describe the SSRI Prozac?
- psychological effects are controversial (could be overprescribed)
- changes in people without a diagnosed disorder caused them to be less neurotic
- makes negative emotions less severe
What fundamental dimension of personality is serotonin related to?
stability: combination of conscientiousness, agreeableness and emotional stability
