Limbic System Part 2 Flashcards
What are the three manifestations of emotional experiences?
ANS (visceral, BP for ex.), Behavioral (eg. facial expressions), Subjective feelings (drives, desires)
What parts of the brain are involved in emotional responsivity and expression?
prefrontal cortex (orbitofrontal , vmPFC), anterior cingulate gyrus, insula, amygdala
What are feelings?
subjective experience of an emotional state based on active interpretations of physiological changes in the body
The physiological component of emotional experiences is mostly mediated by what nervous system?
the ANS
What does the insula do?
a viscerosensory cortex that maps internal body states for emotional awareness- gut feelings, temperature and pain senroy, feelings related to self (how do I feel? am i thirsty, hungry, tired….). integrates bodily states into higher-order emotions
What is the difference in function between the posterior and anterior insula?
the posterior insula assesses interoceptive and exteroceptive information on pain, temp, touch, etc. send it to the anterior insula for perception of those states. anterior insula is aided by ACC and PFC.
How do the insula and cingulate gyrus work together?
insula is the limbic sensory cortex for novel stimuli, while the cingulate processes motivations and actions generated by those emotions
anxiety disorders and fear conditioning are often associated with _________
hyperactivity of the insula
Empathy is mainly generated by:
anterior insula
How does empathy work?
observations of emotionally laden action generates an ‘as if’ construct that entails viscero-motor aspects of the emotion as if it were a first-hand experience. Requires the prediction of physiological reactions to a stimuli
What is the function of the amygdala?
cognitive-emotional interactions, consolidating them into memory- attention and intensity of interpersonal emotions.
Regulates visceral and behavioral responses to fear/anxiety
What are the three ascending and descending projections from the amygdala that contribute to affective attention?
- amygdala processes memory throughout the cortex (ascending projection)
- efferent projection to the visual cortex shape perception and awareness
- amygdala –>hypothalamus –>brainstem = descending pathway for physiological effects (ANS)
What are some visceral responses that the amygdala mediates in response to fear?
increased HR, dec salivation, stomach ulcers, vigilance, urination, defecation, startle resposes….
Why does the amygdala respond more to fearful/startled faces than angry faces?
because it is readily engaged in ambiguou circumstances that require vigilance and attention (What are they afraid/startled by?)
How does the amygdala maintain vigilance?
the amygdala activated the basal forebrain nuclei, increases acetyl choline that activates the cortex, particularly the sensory cortex
coupling of sounds with electric shock to generate responses from the amygdala is called….
classical/Pavlovian conditioning, utilizing emotional memory
the _______encodes emotional memory and consolidates it as long term memory
the hippocampus
During recall of emotional memory, the _______activates the _______ and ______ that express autonomic and behavioral aspects of learned emotional responses.
amygdala, brainstem, hypothalamus
How do the amygdala, hippocampus and mPFC work together during a fearful situation (eg. seeing a snake)?
- Amygdala and mPFC retain association of the snake with fear.
- the mPFC regulated the amygdala response
- the hippocampus add context (is the snake in a cage or wild, is it hissing/rattling?)
What areas of the brain are in the cue-processing system?
amygdala, sensory cortices (visual, auditory), posterior insula, parietal and temporal association areas
What areas of the brain are in the context processing system?
vmPFC, hippocampus, anterior insula, anterior cingulate gyrus
is amygdalar emotional memory retrieval conscious or unconscious? how do we know this?
unconscious. experiments in which an angry face was shown, followed 15msec later by a neutral face yielded no perception of the angry face but ANS responses did occur
What structure mediates the unconscious nature of amygdalar emotional memory retrieval?
the pulvinar nucleus (also in blindsight pathway)
What structure generates conscious memories about an emotional event? What type of memory is this?
the medial temporal lobe (hippocampus)- this is episodic memory
What structure generates expressions of emotional responses? What type of memory is this?
the amygdala, this is semantic memory
How are fear memories erased?
They’re not erased, they’re overridden. The vmPFC inhibits the amygdala. This is critical for adapting to new situations
How does psychological stress result in strengthening of fear conditioning?
during stress the amygdala activates stress pathways in reticular formation and hypothalamus –> increased NE and DA which modulates the amygdala and the cortex–>inhibits the PFC, so inhibition of amygdala fear memories no longer present
During stress, attention regulation switches from _______ to _________.
top-down to bottom-up control
How does propranolol reduce anxiety?
a b-adrenergic antagonist, it inhibits the effects of NE. normally during stress, NE and cortisol work to enhance amygdala functions in increasing stress and sympathetic responses
Lesions to the amygdala often present with what symptoms?
inability to recognize facial expressions, esp those of strong emotions. less aggression, inappropriate sexual behavior, inability to link past experiences to stimuli that have important behavioral consequences. no sense of personal space
Anxiety and anticipation is thought to be mediated by:
the insula
People prone to anxiety show an enhanced ______ response to an averse stimulus
insular
working memory is what kind of function?
an executive function
What is the major region of the brain involved in working memory?
the dorsolateralPFC
What kind of executive control functions does the dlPFC do?
refining, formulating goals, solving problems, sustaining attention, screening distractions (meaning) and regulation behavior/emotion. inhibits inappropriate emotions. IMPULSE CONTROL and WORKING MEMORY
What is a working memory?
underlies consciousness- dlPFC generate persistent activity to a stimulus, activity to sensory association cortices
The medial and orbital PFC generates mainly ______ and connects to what structures?
medial and orbital PFC generate emotional aspects of a stimulus or reward aspects of a task. connect to anterior insula, hippocampus, amygdala
The lateral PFC generates mainly ______ functions
executive functions (eg. planning, selective attention, regulation of behavior)
What structure is affected in ADHD, how is it affected?
the dlPFC is underactive, with weakened connections to other brains, leading to poor sustained attention and weaker impulse control
How do NE and DA affect working memory?
low doses—> nonalertness. optimal levels generate alertness, high levels generate tress, reduce performance and enhance distractibility
What genetic alterations have been associated with ADHD?
mutations to a2A NE receptor and dopamine b-hydroxylase genes have been assoicated with ADHD. (these lead to decreased NE)
late maturation of what structure is thought to be associated with risk-taking behavior in adolescents?
dlPFC
