limbic and physiology of emotion Flashcards
Describe the anatomy of Broca’s “Great Limbic Lobe.
look at a diagram
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.
Papez’s Circuit: emotion is not a function of any specific brain center but of a circuit that involves 4 basic interconnected structures, the hypothalamus w/ mamillary bodies, anterior thalamic nucleus, the cingulated gyrus, and the hippocampus.
emotion, 3 fundamental components
Emotion: complex psycho-physiological experience of a state of mind as interacting with biochemical and environmental influences.
• Three fundamental components:
o 1). Physiological arousal
o 2). Expressive behaviors, actions, and tendencies
o 3). Conscious experience
• Associated: mood, temperament, personality, and motivation.
• Emotion and motivation are linked ==> emotional physiology linked to motivation and the motor system
• Subjective experience occurs in conjunction w/ disposition towards certain stereotypical behaviors/movements.
• Can produce “automatic” reactions.
mood
Affective states. While emotions have a clear focus, a mood tends to be unfocused and diffuse.
• Involves a tone, intensity, and a set of predictions about future experience of reward or punishment.
• Change with expectations of future pleasure or pain, moods, being diffused and unfocused, and thus harder to cope with, can last for days, weeks, months, or years.
• Hypothetical constructs depicting an individual’s emotional state.
cognition
a sense for the processing of information, applying knowledge, and changing preferences. It includes such processes as memory, attention, language, problem solving, and planning.
motivation
states that bias towards specific action patterns or patterns of behavior.
Relate the roles of amygdalae to current theories of emotion and theories of decision-making.
primary roles in the formation and storage of memories associated w/ emotional events. Creates associations between sensory stimuli and specific behavioral and autonomic responses.
• What do lesions to the amygdala do?
o Impairs the acquisition and expression of Pavlovian fear conditioning.
• Structures of importance:
o Central nucleus: involved in the production of fear responses, including freezing, tachycardia, increased respiration, and stress-hormone release. Mediates EXPRESSION of emotional responses.
• Connected to the lateral nuclei to elicit fear behavior.
o Lateral nuclei: memories of emotional experiences imprinted in strength of synaptic connections here.
o Bed nucleus of the stria terminalis: derivative of the central nucleus of the amygdala that mediates the release of pituitary-adrenal stress hormone CRH (Corticotropin-Releasing Hormone).
• CRH: causes the adrenal gland to release epinephrine and cortisol.
• Sensory stimuli reach the basolateral complexes of the amygdalae, esp lateral nuclei, where they form associations w/ memories of the stimuli.
o LTP: long term potentiation, the association between stimuli and aversive events they predict.
• Appetitive conditioning: positive conditioning that the amygdalae is involved in, but there isn’t a clear anatomical location in the amygdala.
Cingulated cortex role in emotion
determines experience of emotion
Hypothalamus role in emotion
emotional expression
where does the cingulate gyrus project?
to the hippocampus
where does the hippocampus project?
to the hypothalamus by way of the fornix
where do hypothalamic impulses go
relay synapse on anterior thalamic nuclei on their way to the cortex
How does emotional experience in the cingulated becomes expression?
indirect transmission to the hypothalamus
how does hypothalamic expression get back to cingulate gyrus?
Hypothalamic expression goes back to cingulated through thalamus anterior nucleus
Is hippocampus involved with emotion?
no
Relate the roles of ventral striatum to current theories of emotion and theories of decision-making.
contains the nucleus accumbens and gets reinforcing VTA neuronal projections. Projects the output back to the VMPFC.
• Critical for generating predictions about the risks and rewards associated w/ given behaviors.
• Can have synaptic plasticity and associative learning.
Relate the roles of ventral tegmental area to current theories of emotion and theories of decision-making.
in the midbrain adjacent to the substantia nigra. VTA neuronal pathways project to the nucleus accumbens of in the ventral striatum.
• VTA releases dopamine in response to errors in predictions about reward.
o Predictions likely calculated in PFC and amygdala (which project to VTA).
o Dopaminergic projections: Nigrostriatal, Mesolimbic, Mesocortical (VMPFC) , and Tuberoinfindibular.
o VTA neuronal pathways project to nucleus accumbens in ventral striatum, which when stimulated, is highly reinforcing.
• Presence or absence of dopamine can reinforce or reduce activity in networks that generate predictions about the risks or rewards of a given behavior.
• Excess dopamine: excessively reinforce networks that were active during behavior that produced the dopamine surge (how cocaine becomes addictive).
Relate the roles of ventromedial prefrontal cortex to current theories of emotion and theories of decision-making.
necessary for the prediction of consequences, but not for registering the actual consequences. Pts demonstrate inadequate inhibition of aggression, sexual behavior, anxiety, and appetitive functions and to correctly employ these behaviors in the appropriate settings.
• Lesions to the VMPFC - Characteristic performance on the Iowa Gambling Task
o Pts continue to to draw from bad decks, even though they are losing.
o Do not display the typical anticipatory emotional response (stress responses) to an impending punishment (losing money from drawing form a bad deck).
o They DO have intact stress responses to the receipt of actual rewards and punishments, which suggests they can still register the actual consequences.
