Lecture 2 - Neuroscience of Emotions Flashcards
Why may neuroscience be helpful in research of emotions? How would we call this field?
- Everything, including e., comes from the brain
- Studying various questions:
- Are e. separate from te cognition?
- What’s the variaty of e.?
- How do basic as opposed to complex e. work?
- Discovering underlying mechanisms of psychopathology
What “model” did MacLean propose in 1949?
- The Limbic system
- based on investigating clinical populations e.g. Kluver-Bucy syndrom
- Plus knowledge that hippocampus seems to be connected to e. processing
What areas does the Limbic system include?
NOTE: depends on who you ask
- Cingulate cortex
- Hippocampus
- Anterior thalamus
- Hypothalamus and mamillary bodies
- Some researchers also add:
- Amygdala
- Orbitofrontal cortex (+ parts of the medial PFC)
What should we know about the limbic system?
- Evolutionary old and universal system
- Similar in diff animals
- Emotional processing serves an adaptive function of interacting with the environment
- NOT unique to e. processing
What’s the Panksepp’s idea of e. processing?
What did Berridge add?
- Brain uses multiple layers to conduct such function
- Neocortex = planning, bonding, appraisal
- Limbic system = communicative e.
- Reptilian brain = emotion reflexes
- Berridge: emotional processing has shifted upwards in humans i.e. going towards neocortex
Are emotions localized to specific brain regions? If yes, which?
- Not really, maybe some of the most basic emotions e.g. fear
- Other than that regions involved (somehow) include:
- Amygdala, hippocampus, ACC, Insula, ventral striatum, Orbitofrontal cortex, periaqueductal gray
What is amygdala involved in (3)?
- Processing of basic emotions e.g. fear
- In collaboration with hippocampus = encoding of emotional memories
- Learning + representing emotional value, salience
Explain the experiment demonstrating involvement of amygdala in fear conditioning of rats.
What about fear conditioning in humans?
Plus:
- Explicit memory intact: patient knew she
would receive a shock
- Implicit memory impaired: no skin
conductance response visible
Could “amygdala lesion” patient’s response be explained by them completely loosing the fear response?
What does Damasio’s somatic marker theory postulate? Which brain regions are connected to it? What if they’re damaged?
= prior experiences (previous outcomes of our decisions) lead to changes in the body/brain (=somatic markers) that can help with the upcoming decisions
- Somatic markers give as the hut feelings
- SM are processed by OFC (retrieval of the marker) and amygdala (“putting a stamp”)
- Damage in either of them leads to impaired link between decision ourcomes and emotion -> disrupted decision making
What happened to Phineas Gage?
- I’m sure you remember the story :)
- Personality changes due to damaged PFC:
- impatient
- obstinate
- inappropriate humor
- indecisive
- unable to settle on any of
the plans he devised for
future action
What are the clinical characteristics of Orbitofrontal Syndrom?
- Disinhibited, impulsive behavior
- Inappropriate humor, euphoria
- Emotional lability
- Poor judgment and insight
- Distractibility
- NOTE: some individuals have genetically optimal levels of dopamine -> stimulation in frontal regions -> better attentional control
How does Damasio’s theory work in a scheme?
1) First time going through ABCD
2) After person has learned from the experience = ABD
Explain how did they test Damasio’s theory on the Iowa Gambling task.
- Picking cards to increase profit, switching however one wants
- BUT there are Good and Bad decks
Findings:
- People with lesions in amygdala or VM
- Did NOT show any learning curve
- Didn’t exhibit difference in skin condactance between decks
=> impairment in decision making (even if they consciously know about the bad decks), increased risk taking
What is stated by LeDoux’s Dual Route Theory?
= there are 2 pathways for processing stimuli
- High/cortical indirect road
- Identify stimulus ->
evaluation/appraisal -> action
- Low/subcortical direct road
- Shortcut via thalamus and amygdala ->
action
If LeDoux is right - Humans should be able to respond more quickly to emotional stimuli than to neutral stimuli.
Do we have evidence for this claim?
Research:
- Presented participants with an array of pictures (3x3) amongst which there was one that didn’t fit
- E.g. 1 snake among 8 flowers or 1 flower among 8 snakes
-> Calculated how fast could people respond to the target (misfit)
Findings:
- Shorter reaction time for emotional stimuli i.e. snakes compared to flowers
- NOTE: done on people with fear of snakes (for others the effect size may be smaller)
If LeDoux is right - Amygdala should be involved in recognizing threat and signal body for fast response
Do we have evidence for this claim?
Research - attentional blink paradigm
- P. presented with random words on a slide (one by one) -> the red words = targets -> first T1 = distracter -> T2 = target identification
- T2 either neutral or negative connotation e.g. rape
Findings:
- No difference in attentional blink between controls and amygdala lesions for NEUTRAL
- BUT in NEGATIVE controls became significantly better at identifying T2 than amygdala lesions (those didn’t change)
What is the Kluver-Bucy Syndrome? How does it show itself - in monkeys and humans?
= neurological disorder characterized by bilateral damage/removal of anterior portion of temporal lobes i.e. amygdala
- Monkey after a surgery due to temporal lobe epilepsy
=> hypersexuality, not caring for offsprings, no fear of snakes, approaching threats showing abuse of offsprings
- Seems to be similar in humans e.g. going through dangerous allay even though one has been robbed here previously
If LeDoux is right - We don’t need a visual cortex and still react adequately to stimuli of threat
Do we have evidence for this claim?
Research - affective blindsight with TMS
- Participants fixate on a point -> stimulus with 4 faces, 1 odd and the rest same, is flashed -> TMS is applied at various times:
- 50, 70, 90,…290ms
-> P. either asked about:
- Location of stimulus
- Emotion displayed
Findings:
- Around 110ms emotions were correctly identified significantly more often than location (that still suffered blindsight)
How did they test Passoa’s idea?
Research:
- P. viewed pictures of faces that displayed either neutral or fearful expression -> over each face there were red letters going towards the middle -> P. had to indicate which one’s the odd letter e.g. in ONO+OOO
- In addition
- People were electricuted when fearful face was presented
- Letters had to difficulties: easy X hard
-> measured activity of amygdala
Finding:
- More amygdalar activation towards fearful stimulus in the easy condition
- BUT in hard condition the activation for fearful and neutral almost equal
Compare images/schemas of LeDaux’s and Pessoa’s models.
How did they demonstrate top down influence over emotional processing?
Research - whether lPFC causally regulates the influence of emotional info on judgement
- Recorded resting EEG as the baseline
- Applied cTMS
-> P. fixated on a point -> briefly shown a happy or fearful face -> making judgements about likeability of a novel face
Findings:
- Inhibition of lateral PFC biased the decision according to the previously shown expression
- If shown happy -> way more likeble
=> lPFC prevents bias in encoding
Why would we claim that amygdala is a system than a unified region?
The structure seems to have multiple nuclei that innervate different parts of the brain
- For example look at the comparison of BasoLateral Amygdala and centromedial amygdala
- seed region -> shows its connections to the rest (i.e. looking at correlations)
- BLA vs CMA -> looks at how much more activation there is compared to the othe
