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
cannon-bard

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