physiology of emotion Flashcards
Understand the Anatomy of Broca’s “Great Limbic Lobe”
Located on medial surface of brain, right under the cortex. Contains several gray matter nuclei and is nonisocortical (possess less than 6 layers). Emphasized connections of olfactory apparatus with limbic lobe
What is the rhinencephalon
combined olfactory and limbic lobes.
what are the structures of Papez’s circuit and what did he propose they do
Papex argued that emotion was a function of a circuit involving the hypothalamus with its mamillary bodies, the anterior thalamic nucleus, the cingulate gyrus and the hippocampus. He believed that the cingulate gyrus was primary and all other structures listed here were secondary. He proposed the hypothalamus governed expression of emotion (heart rate, sweating, etc)
Recognize that “Papez’s circuit” and hypotheses about a “Limbic System” involve some structures that are, and some that are not involved in the physiology of emotion
While the cingulate gyrus, hypothalamus and anterior thalamic nuclei play a role in emotion and motivation, the hippocampus is not involved in emotion, but rather plays a role in memory.
What structures were not included in Papez’s circuit that also play a role in emotion?
Ventral-medial frontal lobe (orbitofrontal cortex), the amygdala, ventral striatum (nucleus accumbens), and several brainstem structures, notably the dopaminergic neurons of the ventral tegmental area (just medial to the substantia nigra pars compacta).
define emotion
complex psychophysiological experience of an individual’s state of mind as interacting with biochemical and environmental influences. fundamentally involves “physiological arousal, expressive behaviors, and conscious experience”.
define mood
Affective state. mood involves a tone and intensity and a structured set of predictions about future experience of reward or punishment. It is a hypothetical construct depicting an individuals emotional state
compare emotion and mood
both are affective states. However, an emotion tends to have a clear focus (i.e. its cause is self-evident), while a mood tends to be more unfocused and diffuse. Emotions are instant and can change with expectations of future pleasure. Mood is harder to cope with and can last for days to years.
define cognition
refers to a faculty for the processing of information, applying knowledge, and changing preferences. includes such processes as memory, attention, language, problem solving, and planning.
define affect
refers to the experience of feeling or emotion. external and dynamic manifestations of a person’s internal emotional state
Define personality
Characteristic patterns of thoughts, feelings and behaviors that a person exhibits fairly consistently throughout life
Is emotion a bottom-up or top-down process
both! Bottom up occurs when emotions are elicited in an automatic fashion, largely as a reflex reaction to certain perceptions, and top- down occurs when emotions may be generated by reflection about the likelihood of favorable or adverse consequences of a situation
Function of amygdala
formation and storage of memories associated with emotional events
How does the amygdala aid in formation/storage of memories
Sensory stimuli reach the basolateral complexes of the amygdalae, particularly the lateral nuclei, where they form associations with memories of the stimuli. The association between stimuli and the aversive events they predict are mediated by long-term potentiation (LTP).
How do memories elicit fear
Memories of emotional experiences in the lateral nuclei elicit fear behavior through connections with the central nucleus of the amygdala and related bed nuclei of stria terminalis.
Damage to what area of the brain impairs the acquisition and expression of Pavlovian fear conditioning
amygdala
Function of central nucleus of amygdala
The central nuclei mediates expression of emotional responses and are involved in freezing (immobility via signals sent to central gray), tachycardia (rapid heartbeat via signals sent to lateral hypothalamus), increased respiration, and stress-hormone release.
Function of bed nucleus of stria terminalis
This is a derivative of the central nucleus of the amygdala. mediates the release of pituitary-adrenal stress hormone (Corticotropin-Releasing Hormone, CRH) in response to fear. CRH causes the adrenal gland to release epinephrine & cortisol.
What is the iowa gambling task
Subjects are given 4 decks of cards. Each time they choose a card they win some money. Every so often, however, a card will indicate a monetary penalty. Some decks are “bad decks” with more losses over the long run, and some are “good decks” that will lead to gains. Most healthy participants, after 40-50 trials, are good at sticking to the “good” decks
How do patients with damage to the ventromedial frontal cortex/oritofrontal cortex perform on the Iowa gambling task
Patients with VMPFC damage or dysfunction continue to draw from “bad” decks, even though they know they are loosing. While normal subjects develop stress responses to the bad decks, VMPFC damaged patients don’t develop this anticipatory phsyiologic reaction to impending punishment.
Function of ventromedial frontal cortex/oritofrontal cortex
predicting consequences. NOT necessary for registering the actual consequences. Damage to this area results in inadequate inhibition of aggression, sexual behavior, anxiety, and appetitive functions. They also fail to correctly employ these behaviors in appropriate circumstances.
Location of ventral tegmental area
medial forebrain
What type of neurons are in the ventral tegmental area
dopaminergic neurons
Function of ventral tegmental area
Project to the nucleus accumbens in the ventral striatum where it plays a role in reinforcement. Also projects to ventral striatum, amygdala, other limibc and cortical areas
Where does the nucleus accumbens project to and from
receives input from and projects output back to the ventromedial frontal cortex, in addition to receiving input from ventral tegmental area
describe the VMPFC-nucleus accumbens corticostriatal loop
Is a network that can, through the presence or absence of dopamine, reinforce or reduce the activity in networks that generate predictions about the risks or rewards of a given behavior. Excessive dopamine in this circuit will excessively reinforce the networks that were active during the behavior that produced the dopamine surge. ventral tegmental area releases dopamine > nucleus accumbens > VMPFC >
