Social & Affective Neuroscience
Foundations of Affective Neuroscience
Theories of emotion
Discrete
There are basic emotional categories such as angry, sad, happy, and disgusted.
Dimensional
All emotions can be characterized by where they fall on a 2-dimensional plane, where one axis is "valence" and the other is "intensity"
Process-oriented
All emotions invoke different biases toward responses to a particular stimulus. For example, anger involves a negative affect but an approach motivation, whereas sadness involves negative affect but a withdrawal motivation.
Evolution over time
I think theories of emotion have gradually shifted to dimensional models, and I believe this theory might have more neuroanatomical support.
Newer methodological approaches that scan the brain have helped us identify how emotions are registered in the brain, allowing us to see emotions as a vertically-integrated process
Individual differences in affective processing styles
Left-PFC vs. Right-PFC
baseline activation
Affective Chronometry
Sustain Envelope of Emotion
How long does an emotion take to run its course?
Emotion/Cognition Interactions
Fear conditioning
Acquisition
Extinction
Contextual gating
Reconsolidation
Reconsolidation "neutralizes" the "unsafe" memory, turning it into a "safe" memory
Extinction learning
A new "safe" memory is created alongside the old "unsafe" memory - over time that "safe" memory becomes the most activated, but the "unsafe" memory can always spontaneously reappear given the right context.
Amygdala
Fear learning and conversion to motor control
PFC (especially vmPFC)
PFC modulates the ITC of the amygdala to help with extinction learning by suppression.
vmPFC aids memory of extinction learning.
Pavlovian/Behavioral Paradigm
US to create UR paired with CS, in order to link CS and UR, becoming CR.
Emotional influence on memory
Brain Body Links in Decision Making
Somatic Marker Hypothesis
The vmPFC links situational emotional stimuli with body states, which eventually become learned such that the body states can cause the production of emotional states that guide decision making (through Amygdala)
Neural substrates
Tests of hypothesis
Iowa gambling task pt. 1
Insula-damaged patients perform worse than neurotypical controls
Iowa gambling task pt. 3
SCR in healthy controls guides decision-making without people being consciously aware. vmPFC-damaged patients do not have anticipatory SCRs, and thus cannot have this response.
Iowa gambling task pt. x
Amygdala-damaged patients do not exhibit SCRs at all, which means the amygdala is responsible for the execution of bodily states.
Critiques of test
Bias
Test is biased towards bad decks, because insula-damaged patients have trouble changing ANYTHING
Ecological validity
How representative is the card game of real-world decision making?
Critiques of theory
As-if loop is relatively unfalsifiable
Insula
- Detects body state (interoception)
Amygdala
- Execution of bodily states due to emotional stimuli, such as SCR.
Interoception
Literally the perception of what is inside - how the body perceives its physiological state.
Iowa gambling task pt. 2
vmPFC patients do not show anticipatory SCRs when selecting from risky decks, despite normal SCRs to reward and punishment.
Example
The body can detect:
- faster heart-rate
- SCR
- stomach ache
Emotion Regulation
Gross Model of Emotion Regulation
Situation selection
- antecedent
Situation modification
- antecedent
Attentional deployment
- antecedent
Appraisal
- antecedent
Response expression
- post
Reappraisal
Changing the meaning attached to an emotional stimulus.
Suppression
Inhibiting the expression of emotion
Consequences of reappraisal
Affective
- Fewer negative emotions
Social
- No difference than acting naturally
Behavioral
No difference in SCR compared to "view" condition
Consequences of suppression
Affective
- Fewer positive emotions
- Same level of negative emotions
Social
- Worse memory
- Higher blood pressure of partner
Behavioral
- Higher SCR compared to view and reappraise conditions
Neurophysiological evidence
Executive regions regulate sub-cortical structures related to emotion
Critiques of the model
Linearity
Comprehensiveness
Are we always regulating?
Nothing about social regulation
James-Lange Feedback Theory
- Emotions originate from bodily feedback to emotional stimuli
"We are afraid because we run, we do not run because we are afraid."
Cannon-Bard
- Early parallel model of emotion
- Centered on diencephalon
Papez Circuit
- Pre-dated limbic system model
- Also parallel process (stream of thought vs. stream of feeling)
- Differentiated conscious feeling and physiological expression
Limbic System Model
- A sub-cortical system is primarily responsible for the processing of emotion
Hypothalamus
Thalamus
Hippocampus
Amygdala
Vertically-integrated models
Emotion involves activity in many areas of the brain, from the cortical structures that are responsible for executive function to the sub-cortical structures that are responsible for fear conditioning.
Critiques
Why the hippocampus?
Only sub-cortical structures?
Cortical pathway
- Responsible for the feeling of emotions
Sub-cortical pathway
Responsible for the expression of emotions
Role of diencephalon
Cingulate Gyrus
- Center of emotion
Socioemotional Perception & Communication
Perception of Social Cues in Face
Dual system model of face perception
Identity processing
- Determines the identity of the target
Affective processing
- Determines the affect, intentions of the target
Ventral cortical pathway
- Including visual area
Interaction effect
Recent studies have shown that these 2 pathways are interdependent through feedback loops.
Dorsal cortical pathway
Superior temporal sulcus interacts with subcortical emotional structures
Evidence for dual system model
Spatial frequency experiments
Different pathways activated for low spatial frequency (emotion) and high spatial frequency (identity)
Gaze processing
Use in social situations
- Signals intent
- Could be used in joint attention
Processes in brain
Gestural cues & biological motion processing
The role of the STS
Sensitive to implied or actual biological motion
Hand gestures
STS responds more actively to meaningful actions
Light experiment
Social value of emotions
Vocal emotions
Social functions of emotion
Affiliation
- Emotions that serve to create a deeper bond between people or groups
Distancing
- Emotions that serve to draw boundaries between people
Effect on group-based behavior
Affiliative emotions
- Sadness
- Happiness
- Excitement
Conveying affect vocal theories
Our voice modulates to reflect our affect and communicate that with others.
- Discrete: our vocal tone indicates specific emotions
- Dimensional: our vocal tone includes both valence and level of arousal
Social function != social outcome
- Intentions for emotion can be different than what results
Distancing
Distancing emotions expressed to dissimilar member of group creates affiliative emotions among group members
Fo
Fundamental frequency is what best characterizes our voice (maybe)
Distancing emotions
- Anger
- Contempt
- Pride in self
Dominance and submission
- Anger typically works to show dominance and moral superiority
Adaptiveness
- Can be useful in showcasing emotions that can right wrongs (couples who fight more [to a point] stay together longer)
Inductive vocal theory
- Our voice modulates to get other people to respond to something.
Based in evolution: voice carries farther than sight, and can alert others to danger
What does Fo signify? Arousal, or other aspects like valence?
Experimental evidence lacking here
- Actor study with bad identification of affect (discrete)
What is affective processing style?
Individual differences in valence-related emotional reactivity and regulation.
Left-PFC
Goal-approach responses, mechanisms to achieve goals, more positive affect
Right-PFC
Behavioral inhibition, vigilant attention, accompanied by negatively valenced emotional states
Studies to show this
Right-PFC activation correlated with BIS self-reports.
Consistent over time to prove trait, rather than state status
Left-PFC activation correlated with BAS self-reports
Consistent over time
Anger dispositions correlated with left-PFC activation
Teases out difference between positive-negative valence and approach-avoidance models
Left-PFC lesions associated with symptoms of depression
Depressed people are also more likely to have less baseline activity in left-PFC.
Inhibited babies show higher less left-PFC activation
They are also more likely to cry at distressing events
2 Factors
Dispositions
- Amygdala reactivity
- Resilience (IPFC)
Emotion regulation strategies
- Reappraisal
- Rumination
- Distraction
Why fear?
Rapid learning
Less susceptible to cultural influence?
Easy to measure
Translates across species
Hippocampus
Contextual gating of fear responses
Studies to show this
Patient S.P.
Bilateral amygdala damage prevents learned SCR, although able to make declarative statements about association between CS and CR.
Declarative vs. non-declarative memory
Declarative does not always match up with non-declarative
Rat studies
Amygdala lesions prohibit acquisitions of fear responses
Imaging studies
Show thalamus, amygdala, and cingulate cortex could be a system for acquiring fear.
Studies to show this
vmPFC lesions in rats inhibited memory of extinction 24 hours after extinction training.
Stimulation of PFC neurons in rats stimulates ITC neurons which reduces "fear output" (motor, SCR) from Amygdala.
Memories enter "labile state" for about ~6 hours, during which extinction training is more effective.
Fear reinstatement
Context can prompt the spontaneous return of fear responses
Studies to show this
Hippocampal lesion studies in rats and amnesic patients show difficulty with contextual reinstatement of fear.
Emotion enhancing memory
Translating models to real-world studies
Emotionally arousing stimuli benefit memory encoding and retrieval
Encoding
Amygdala lesioned patients do not have enhanced memory for emotionally arousing words.
Amygdala-MTL interactions predict successful emotional memory encoding
Seen through correlated activity
Valenced stimuli benefits mediates memory encoding and retrieval
Positively or negatively valenced words are more likely to be remembered (even in patients with amygdala damage)
Release of hormones predicts greater encoding capacity
Semantic networks are better created with affective valence, because it acts as a category under which words can be placed.
Retrieval
Vocab
Familiarity
Remembering that an event happened, but not its contextual details
Evidence
Year-long picture experiment
Recollection
Remembering an event and its contextual details
Enhanced activity in Amygdala and MTL for retrieval of emotionally arousing pictures.
Autobiographical
Intensity matters more than valence for accurate retrieval according to autobiographical studies
Emotionally arousing pictures retrieved more accurately than neutral pictures after one year
Hippocampus and r-PFC implicated in access of emotional memory
Visual and l-PFC implicated in elaboration of emotional memory (reliving)
Duke basketball
Unique case
Opposite valence for opposing teams
Equal intensity for each shot
Highly emotionally intensive event
Body Loop
Physiological reactions send signals to the brain that guide emotion and thus decision-making
As-if Loop
Relevant brain structures produce feeling without registering a physiological response
Vague in details
Why do somatic markers help?
Constrain the decision-making space
Cognitive processes involved require more than one isolated one.
vmPFC
- Learns links between emotional stimuli and body states
Posterior
Responsible for taking in sensory-based inputs
Anterior
Responsible for integrating posterior signal with social/contextual clues
Insula activation correlated with heartbeat detection
Culture and Emotion
STS
- Perceptual coding of another's gaze direction
Parietal lobe
- Attentional orienting through gaze following
medial PFC
- Joint attention
Monkey studies have dissociable regions for emotion and identity processing in STS.
Amygdala
- Analayzes intensity of emotion
Amygdala damaged patients have trouble analyzing intensity of emotions, especially fear.
Sclera of eyes is all that is needed to activate amygdala response to fearful expression
Responds to fearful faces even if attention is not being deployed
Amygdala modulates FFA
FFA activated with high-spatial frequencies whereas amygdala activated with low spatial frequencies
Anterior STS
- Elementary gaze direction
Posterior STS
- Gaze and head direction
Studies showed that STS has cells that fire to specific turnings of the head and specific gaze directions
Responds with saccades that follow someone else's eye movement.
mPFC responds more when following a dot also followed by another person.
Lesion studies show that damaged STS impairs gaze recognition.
Head Movements
Mouth Movements
Lip reading
Implied motion
Ventral vs. dorsal flexion in monkeys
Ventral flexion triggered specific cells in STS
Meaningful mouth movements in monkeys activate regions of the STS. This translated to humans.
Cross-modal activation as STS fires along with auditory cortex
Pictures with implied motion activated STS more than pictures without implied motion.
Functional conflict theory describes why intentions do not equal outcomes. It's because they can be perceived in different ways on different levels.
Affiliative
Interpersonal regulation
What is the role of language in emotion?
How can you test the universality of emotions?
How do cultural attitudes moderate and regulate emotion and emotional displays?
Language can instantiate basic emotions to form culturally specific complex emotions
Dual process model
- Emotion is regulated by culture before it even occurs.
- Self-regulation is the product of culture
- Emotional responses feedback to create culture
Individualism vs. Collectivism
Difficulty in modern era
Removing social mediators
Narrative story-telling
Evidence of Dual-process Model
Cultural reinforcement
Which acts are encouraged, and which acts are discouraged?
Cultural affordances
Which acts are made easier to engage in by the culture?
In therapy, Americans focus on exerting control whereas Japanese focus on adapting to changing circumstances
Subjective well-being is constituted differently. In America, this often comes from feelings of pride, whereas in Japan it comes more often from feelings of duty.
Each offers a different model of self, which in turn influences which emotions can be brought to the surface
Social Identity Theory
Self-esteem comes in part from status of groups with which we identity
Anger vs. contempt
- Anger alone works to resolve difficulties
- Anger with contempt works to create deeper divisions