Biological explanation of emotion Flashcards
Conceptual approaches
Gross & Feldman-Barrett (2011)
-core assumptions of 4 emotion perspective?
emotion generation and emotion regulation depends on your point of view
- core assumptions of 4 emotion perspectives:
1) basic = biological
2) appraisal = cognitive
3) psychological construction = social
4) social construction = cultural - get different answers to the ‘emotion questions’ dependent on which approach you look at
Note: the biological approach places constraints on the other approaches. This is because what happens in the brain and body underpin the emotion (evidence via brain and body for social/ cultural etc)
–> if you can’t put evidence to approach via biology = weak argument
Emotion in the body: Physiology
- inducing emotion from body action
- emotion experience and bodily states (maturational dualism?)
- physiological measures we can use?
evidence:
- inducing emotion from body action
eg. raise upper lip/ tongue out/ wrinkle nose = disgust
- -> actions of our body inform us
- emotion experience and bodily states
ability to sense bodily states (interoception) and physiological reactivity DECLINES in older age, which may impair emotional experience
= known as MATURATIONAL DUALISM (mendes, 2010) (this is evidence we use signals from our body to understand emotion, as because we get older and interoception declines = decline emotional experience) - physiological measures (Ekman & Levenson)
heart rate: lower in disgust; higher in fear/ anger and sadness
galvanic skin response (sweat): higher in disgust/ fear
finger temp: higher in anger; lower in fear
–> use this to deduct what individual is feeling (distinguish between some basic emotions but not all)
Emotion in the body: Physiology
Autonomic nervous system (ANS)
- function?
- structure? (2 systems and functions?)
Dynamic systems view
ANS specificity
–> whether or not emotions are deemed body responses depends on the evidence for emotion-specific ANS activity
(diff conclusions reached - Friedman, 2010)
- function: = control system that maintains internal conditions of the body (organs/ glands/ muscles) in response to environmental events
controls processes such as: digestion, blood flow and temp
- structure:
2 main subsystems:
1) Sympathetic nervous system = helps with demanding actions by increasing heart rate, reducing digestion and constricting arteries
2) Parasympathetic nervous system = helps restorative processes by decreasing heart rate, dilating arteries and increasing digestion
Dynamic systems view:
- ANS has many pathways and components so emotion specificity is possible
- the brain and body are connected in producing a response –> neural systems + feedback from environment
- Thayer & Lane (2000) proposed a neurovisceral model of emotion regulation that integrates neural systems with automatic systems. It is a dynamic systems model involving feedback circuits, that enables the individual to adapt to their environment
Emotion in the body: Physiology Heart - heart rate variability - Porge's polyvagal theory (1995) -evolutionary development?
- small neural net in heart and this allows for bidirectional communication between brain and heart (not just a pump, it may be part of a complex dynamic system)
(historically heart is associated with emotion eg. love)
Heart-rate variability
variation in beat-to-beat interval (more variable = more healthy)
- produced by combined influence of SNS and PNS
(SNS = regular heart beat, PNS = activate via vagul nerve = break of HR)
- SNS dominates in stressful events = reduces variability (greater variability = healthy)
- greater HR variability at base line have greater ability to regulate emotions (so, bad at regulating emotion = LOW HR variability)
- when we generate positive emotions = INCREASE HRV
Porge’s Polyvagal Theory (1995)
- vagus is a family of neural pathways originating from different parts of brainstem
- Dorsal nucleus (DMNX) path DECREASES heart rate
- Nucleus Ambiguus (NA) path influences HRV
Evolutionary development
- reptiles only have DMNX path = produces immobilisation response in response to novel stimuli (instead of fight or flight)
- Mammals - use NA path to repeatedly inhibit cardiac response, but this ‘brake’ is withdrawn to deal with demands eg. fight or flight and under threat DMNX path may produce freezing
- NA has inputs from amygdala and facial nerve = potentially influenced by emotions (things in environemnt)
- May enable prosocial emotions in particular (eg soothing/ compassion)
Emotion in the brain: Neuroanatomy
evidence comes from?
Limbic system
- Papez circuit
- MacLean’s limbic system
evidence for brain structures involved in emotion comes from:
- electroencephalogram (EEG)
- neuroimaging (PET, FMRI)
- experiments (facial action codes, electrical stimulation)
- brain damage studies (to emotion processing centres)
- emotion disorders (anxiety and depression)
- combination of these (eg. neural activation in depressed)
Papez circuit
-Papez (1937) extended Cannon-Bard’s proposal concerning role of thalamus in producing emotion
-identified a neural circuit in which sensory input to thalamus splits into :
1) upstream thought path to cingulate cortex
2) downstream feeling path which loops back to the cingulate
(pathway up from thalamus to higher cortex and down to body)
MacLeans limbic system
- MacLean (1952) proposed the limbic system generates emotion experience by integrating sensations from the external world and the body
- Panksepp (1998) extended this by proposing that each emotion has its own limbic system circuit that readies an individual for a particular action
- The amygdala (one of the limbic structures) and its reciprocal connections to anterior cingulate, insula and prefrontal cortex have been shown to have a major role in generating, processing and regulating emotion
Emotion in the brain: Neuroanatomy
Amygdala
emotional learning of stimuli (2 stages?)
one in each hemisphere
hippocampus v close to limbic system (important for consolidating memories)
- LeDoux (1993) identified amygdala as the critical structure in the limbic system for emotion
- automatically evaluates the emotional significance of the event (ie. primary appraisal)
-responds to emotionally intense stimuli
- emotional learning of stimuli:
1) FAST conditioned response = without cortex involvement
2) SLOW condiitoned response = with cortex = take time to consider actions (Eg. count to 10 when angry)
- key role in pocessing social signals (Esp fear in faces)
- shows heightened activation in some affective disorders (Eg. depression) –> trigger amygdala more due to heightened activation
- doesn’t seem to be involved in experience of emotions ( ONLY EVALUATING THEM)
Emotion in the brain: Neuroanatomy
Cortex - some of its functions in emotion?
- inhibition
= initially assumed to simply inhibit emotions generated in lower brain (damage to OFC has been associated with disinhibited reactions) - Reward learning
= OFC also involved in learning the motivational value of stimuli
Decision-making
= VMPFC appears to use body feedback from previous emotional events to guide decisions (used as evidence for Damasio’s somatic markers hypothesis)
Monitoring
= ACC appears to play a role in monitoring discrepancies between current and desired emotional states
Regulation
= DLPFC activated during reappraisal of negative stimuli, which reduces persons negative emotional response (Oschsner)
Self-awareness
= Insular cortex appears to be important in the experience of emotion, including embodiment, anticipation, recognition and empathy
Emotion in the brain: Neuroanatomy
Lateralisation
- 2 models?
Evidence: selfie takers and instagram
multi-system models
= each emotion has its own neural system
1) Single system model
= right- hemisphere hypothesis (Mills, 1912)
- suggest right is dominant and has a specialised role in processing emotions
(may be restricted to perception and expression of emotion)
2) Dual-systems model
= right associated with withdrawal or inhibition, and hence negative emotions such as disgust/ fear
- left hemisphere associated with approach or activation, and hence positive emotions eg happiness. But anger too (Harmon-Jones et al 2010)
== Valence hypothesis
- selfie takers prefer left cheeks (Manovich, Ferrari & Bruno, 2017) = supports right hemisphere hypothesis that we may be more expressive with left side
- Instagram study found results consistent with valence hypothesis : negative expressed more strongly on left cheek and positive expressed more on right cheek
TO conclude,
recruiting different parts of the brain for different functions of emotion
- weight of evidence suggests: emotion functions are not isolated in single anatomical brain structures
- pattern of activation across different parts of the brain is what makes them specific to emotion
Emotion processes: Neurophysiology
- generating emotions - bottom up vs top down + amygdala activity?
processing emotions
– generating emotions
- emotions arise from top-down (thoughts) and bottom up (senses) processes
- involvement of each??
Oschner et al (2009) FMRI study;
- looked at either unpleasant images (bottom up)
OR
- had to negatively appraise neutral images (top down)
FOUND:
- bottom up activated left and right amygdala; top down only activated left
- bottom up activated areas for perceiving stimuli
-top down activated areas for interpreting stimuli
- experience of affect showed correlation between:
bottom up and amygdala activation AND top down and medial prefrontal areas
SO, emotions may arise from different combinations of bottom-up and top-down processes
AND, treatment could be directed at whether emotional problem is primarly bottom up (info from environment changed) or top down (thoughts about feelings changed)
Emotion in the brain: Neuroanatomy
Regulating emotions: gender differences in reactivity to stimuli
usually no differrence in emotional reactivity to stimuli, but there might be a difference in regulation
- McRae and colleagues (2008) - used FMRI and ps had to stop themselves feeling distressed in response to unpleasant images
(ps had to use reappraisal = top down process)
FOund:
- no gender differences in reactivity to stimuli
- regulation decreased negative emotional experience for both genders (men = less activation in prefrontal cortex, amygdala and ventral striatum)
Conclusion = men may use less effort in cognitive emotion regulation OR women recruit more positive emotions
Emotion in the brain: Neuroanatomy
Interpersonal emotion process - empathy?
Limitation?
empathy:
- some research suggests mirror neurons may be responsible for interpersonal emotion processes such as empathy and sympathy
- specifically, MNs in emotion system are thought to be triggered by the actions (Eg. facial expressions) of another person and thereby generate corresponding emotion in the observer (they’re happy. you’re happy)
HOWEVER, limitation:
- Decety(2010) suggests there is insufficient evidence for this:
found:
- empathy is complex and likley to involve many brain regions
- how we look/ appear to others is important
= some people try to enhance this eg. botox BUT they may appear less emotionally expressive
- Havas et al (2010) - found botox can lead to slower processing of emotional language, because it can paralyse the muscles used for emotioanl expression
= may impair feedback from face = may not understand emotion as well
Emotion in the brain: Neuroanatomy
Emotion and cognitive processes
- decision making
without emotions = v hard to make decisions
eg. no gut feeling when certain emotion centres are damaged
(damasios somatic marker hypothesis)
findings:
- Bechara et al (2000) - patients with VM frontal damage showed they were more likely to choose risky gambles in betting games than controls
- controls had elevated skin response when there was a risky choice and so avoided it
NOTE: for some types of decison making a lack of emotion can be better (Shiv et al, 2005)
