Chapter 13-15 Flashcards
flash-bulb memories
phenomenon whereby emotional memories often recalled more vividly after event
- memories recalled in a “photographic” form
- not actually more accurate than a normal memory, but feel more accurate
memory for emotions
information learned after-the-fact distort memory for emotions
emotion congruence
people remember information better if they learn it and recall it in the same (congruent) emotional state
- example: easier to conjure up a memory in which you were happy when you are currently happy
the limbic system
a complex set of brain structures that lies on both sides of the thalamus, right under the cerebrum
- collection of structures from the telencephalon, diencephalon, and mesencephalon
- supports a variety of functions, including emotion, motivation, and long-term memory
- seems to be primarily responsible for our emotional life and has a great deal to do with the formation of long-term episodic memories
the limbic lobe - Paul Broca (1878)
Broca called the limbic system the limbic lobe and suggested that the entire lobe might be concerned with the sense of smell
circle of papez
James Papez proposed the Papez circuit and that this network of brain structures worked together to mediate emotions
- hippocampus, hypothalamus, anterior thalamus, and cingulate gyrus
Paul MacLean
- expanded on Papez’s model
- termed it the limbic system
- added the amygdala to the limbic system
- claimed that the amygdala brings emotional attributes t hippocampal memory to bring about the formation of emotional memory
no universal agreement on the total list of structures that should be included in the term limbic system, but all authors would include…
cingulate and parahippocampal gyri, hippocampus, amygdala, septal nuclei, hypothalamus, midbrain reticular formation, olfactory areas
some neuroscientists, including Joseph LeDoux
suggest that the concept of a functionally unified limbic system should be abandoned as obsolete because it is grounded mainly in historical conceptos of brain anatomy that are no longer accepted as accurate
emotion
a collection of physiological changes in body and brain states triggered by a dedicated brain system that responds to a particular entity or event: some changes are non-perceptible to an external observer, some changes are perceptible to an external observer
feeling
the signals generated by these changes towards the brain itself produce changes that are mostly perceptible to the individual in whom they were enacted and provide the essential ingredients for what is ultimately perceived as a feeling
- what the individual senses or subjectively reports
emotion may be induced in two different ways
- primary induction
- secondary induction
primary induction of emotion
automatic
secondary induction of emotion
reflective/thoughtful
critical neural structures of emotion
- amygdala
- orbito/ventromedial prefrontal cortex
- insular cortex and cingulate cortex
primary inducers
stimuli that are innate or learned to be pleasurable or aversive; once they are encountered, they automatically, quickly, and obligatorily elicit an emotional response
- example: encountering a fear object (e..g, snake)
secondary inducers
entities generated by the recall of a personal or hypothetical emotional event (i.e., thoughts and memories about primary inducers), which when they are brought to mind (working memory), they slowly and gradually begin to elicit an emotional response
- example: memory of an emotional event, such as encountering or being bit by a snake, evokes fear
trigger structure for emotion from primary inducers
amygdala
trigger structure for emotion from secondary inducers
orbitofrontal cortex/ventromedial prefrontal cortex
neuroanatomy of emotions and feelings
three pathways:
emotionally competent stimulus (ex. snake) –> sensory systems –> amygdala –> visceral motor –> the viscera –> autonomic responses
emotionally competent stimulus (ex. snake) –> sensory systems –> ventromedial prefrontal cortex (anterior cingulate cortex and orbitofrontal cortex) –> orbitofrontal cortex –> visceral motor –> the viscera –> autonomic responses
the viscera –> visceral sensory –> insular cortex –> anterior cingulate cortex (of the orbitofrontal cortex) (also receives input from sensory systems)
patients with ventromedial prefrontal cortex damage
- retained normal intelligence, however
- difficulties planning workday and future
- difficulties choosing friends, partners, and activities
- actions often lead to losses of diverse order: losses in financial status, social standing, family and friends
- choices are no longer advantageous and are remarkably different from he kinds of choices they were known to make in the pre-morbid period
- show a compromised ability to express emotion and to experience feelings in appropriate situations
- show abnormalities in emotion and feelings, along with severe impairments in judgment and decision-making in real-life
deprived of emotional/somatic signal, patients with ventromedial prefrontal cortex damage rely on a reasoned cost-benefit analysis of numerous and often conflicting options, which:
1) degrade the speed of deliberation
2) degrade the adequacy of the choice
Iowa Gambling Task (IGT)
- measures decision-making deficits
- determines if a subject can make a good decision
- used to detect poor judgment and failure to learn from repeated mistakes
- measured emotions as well
behavioral deficit in decision-making is linked to a…
deficit in the ability to generate somatic/emotional signals associated with prior experiences with reward and punishment
ventromedial prefrontal cortex lesions
interfere with the generation of an emotional response from the recall and imagery of an emotional event (secondary induction)
- good memory for the facts of an event, but no emotion expressed with that memory
clinical features and causes of orbitofrontal/ventromedial prefrontal cortex and medial temporal lobe
acute or chronic neurologic disease:
- hemorrhagic leukoencephalitis, herpes simplex encephalitis, and traumatic necrosis of the medial portion of the orbitofrontal/ventromedial prefrontal cortex and medial temporal lobe can precipitate violent rages
- slow growing tumor of the anteromedial portion of the temporal lobe also precipitates fits and rage
children also display these tantrums:
- amygdala develops early but prefrontal cortex later (25 years); children may express “temper tantrums” from early life to get what they want
acquired sociopathy
the personality and decision-making disturbances in patients with orbitofrontal/ventromedial prefrontal cortex (VMPC) damage resemble many of the core features of sociopathy (psychopathy), including: shallow affect, irresponsibility, vocational instability, lack of realistic long-term goals, lack of empathy, poor behavioral control
majority of VMPC patients are not exactly like true psychopaths
- usually begins in adulthood (when the lesion occurs), so not developmental
- generally do not cause physical harm to others