Download The role of Amygdala

The Mapping of Emotion
Dr. Essi Viding
Institute of Psychiatry,
King’s College London
& Department of Psychology, University College London
[email protected]
Mapping of what and
where of the emotion
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Does it need to be a conscious
experience for it to be an emotion?
Simple or complex phenomena?
What is the purpose of emotions?
‘Where’ are they in the brain?
Are emotions opposite of rational?
Emotions as Response
Patterns
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Emotional responses can be:
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Behavioral: expression of emotion
Autonomic
Hormonal
In humans, and higher primates, awareness
of body states contributes to emotion and to
a feeling state
– However, the body state cannot be distinguished
as a specific emotion if it does not have a
corresponding ‘object’ in the surroundings
– I.e. bodily responses are too general, not
specific enough
Does it need to be conscious
to be an emotion?
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Conscious feelings do not equate
emotion
– Basic emotion/affective functions exist in
animals with considerably smaller brains
than humans
– Emotional learning can occur without
explicit awareness
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Mood does not equate emotion
Simple or complex
phenomena?
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If you want to study it in rats, it has to
be (or become) simple
Emotion as a response to
reinforcement or punishment (Rolls,
1998)
Mapping emotions in the
reinforcement space
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Rolls
–
Positive reinforcer
(Emotional Brain, 1998)
Ecstasy
Elation
Omission of positive
reinforcer
Rege
Pleasure
Anger
Frustration
Grief
Sadness
Relief
OR
Termination of
negative reinforcer
Omission of
negative reinforcer
OR
Apprehension
Fear
Terror
Negative reinforcer
Termination of
negative reinforcer
Purpose of emotions?
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Evolutionary functions of emotion
Protection
 Territory defense
 Approach behaviours
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Protection/territory defense:
– Threat behavior:
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A species-typical behavior that warns another
animal that it may be attacked if it does not
flee of show submissive behavior.
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Defensive behavior/submission:
A species-typical behavior by which an animal
defends itself against the threat of another
animal
 e.g. throat baring in dogs
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The Mapping
of Emotion
‘Where’ are the emotions
in the brain?
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Emotion Circuitry
– Amygdala
– Orbitofrontal Cortex
– Anterior Cingulate Cortex
– Insula
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Different roles – but nothing in the
brain acts in isolation
Brain Mechanisms for
Emotion
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Role of the Amygdala
– Lateral/basolateral nuclei:
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Nuclei of the amygdala that receive sensory
information from the neocortex, thalamus, and
hippocampus and send projections to the ventral
striatum, the dorsomedial nucleus of the thalamus, and
the central nucleus.
– ‘Quick and dirty’ processing of information with
potential relevance for survival
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Fear and the Role of the Amygdala
– Basal nucleus:
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A group of subnuclei of the amygdala that
receive sensory input from the basolateral
nuclei and relay information to other
amygdaloid nuclei and to the periaqueductal
gray matter (fight/flight/freezing response).
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The Role of the Amygdala
– Central nucleus:
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The region of the amygdala that receives information
from the basolateral division and sends projections to a
wide variety of regions in the brain, involved in
emotional responses.
Projections to pons, insula, hypothalamus, and medula
for expression and integration of emotional responses
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The Role of the Amygdala
– Conditioned emotional responses (CERs):
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Most emotional responses are a result of
Pavlovian conditioning
– A previously neutral stimulus can take on the come
to elicit an emotional response if paired with a
naturally aversive/reinforcing stimulus
When a tone is paired a few times with a foot-shock,
rat freezing responses start at the tone, prior to the onset of the shock.
The role of Amygdala
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Amygdala as a stimulus-reinforcement
associator
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The Role of the Amygdala
– Perception of emotional expressions
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Particularly negative emotional expressions
– Human brain imaging studies
fMRI: Fearful expression
Amygdala activation
Brains from Ahmad Hariri’s study
Amygdala pathology
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Patients with amygdala damage
– Poor conditioned emotional response
– Poor recognition of fear
– Recent data suggests that amygdala patients fail
to focus on the eyes
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most informative part of the face when recognising fear
Psychopaths – amygdala dysfunction?
– low amygdala reactivity to emotions
– difficulty learning from punishment
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Anxiety - amygdala hyperreactivity?
– Oversensitive threat system?
‘Where’ are the emotions
in the brain?
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Emotion Circuitry
– Amygdala
– Orbitofrontal Cortex
– Anterior Cingulate Cortex
– Insula
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Different roles – but nothing in the
brain acts in isolation
Brain Mechanisms for
Emotions
Orbitofrontal Cortex:
The region of the prefrontal cortex at the
base of the anterior frontal lobes.
 Receives input from dorsomedial thalamus,
ventral tegmentum, and amygdala.
 Outputs to cingulate, hippocampus, temporal
lobe, amygdala, and hypothalamus.
 Involved in using emotion to guide actions
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Orbitofrontal pathology
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Patients with orbitofrontal damage:
– Lack of emotion in decision making
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(lack of risk aversion)
– Poor social judgment (antisocial behavior)
– Poor emotional control (anger)
‘Where’ are the emotions
in the brain?
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Emotion Circuitry
– Amygdala
– Orbitofrontal Cortex
– Anterior Cingulate Cortex
– Insula
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Different roles – but nothing in the
brain acts in isolation
Brain Mechanisms for
Emotions
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Cingulate Cortex
Body representations of emotion
 Feelings of emotion
 Regulation of emotional responses
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– Coupling with amygdala activity in fMRI studies
Anterior cingulate pathology
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Implicated in emotional disorders such
as
– Depression
– Schizophrenia
‘Where’ are the emotions
in the brain?
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Emotion Circuitry
– Amygdala
– Orbitofrontal Cortex
– Anterior Cingulate Cortex
– Insula
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Different roles – but nothing in the
brain acts in isolation
Brain Mechanisms for
Emotions
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Insula
– Role in processing convergent information to
produce an emotionally relevant context for
sensory experience, such as disgust and feelings
of unease
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Warning of potentially noxious stimuli
– An important role in pain experience
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Codes for affective aspects of pain
– Receives an input from central nucleus of
amygdala
fMRI: Disgusted expression
 right insula activation
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Perception of
disgusted faces
preferentially
activated insula
Insula pathology
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Obsessive-Compulsive disorder
– Higher brain activation to disorder
relevant stimuli, as well as other
disgusting stimuli
‘Where’ are the emotions
in the brain?
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Emotion Circuitry
– Amygdala
– Orbitofrontal Cortex
– Anterior Cingulate Cortex
– Insula
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Different parts of the circuitry
selectively affected in different
disorders
‘Where’ are the emotions
in the brain?
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Emotion Circuitry
–
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–
–
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Amygdala
Orbitofrontal Cortex
Anterior Cingulate Cortex
Insula
Different roles – but nothing in the brain
acts in isolation
Brain in action: Example of the complex circuit of
brain areas involved in emotion processing
Video from Ahmad Hariri
Brain in action: Example of the
complex circuit of brain areas involved
in emotion processing
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Initial amygdala response  not much
conscious processing
The anterior cingulate rides to the
rescue of amygdala and regulates the
initial emotional response
Finally the complex emotion of
‘embarrassment’ sets in
Are the emotions
opposite of rational?
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Yes and no.
Can serve us well in situations where we
need to react quickly
– i.e. gut reaction can initiate the best response
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Can give us non-verbal cues about people’s
trustworthiness and intentions
Emotional responses can also go awry and
make everyday life difficult
– Different emotional disorders have different
‘brain signature’ as briefly discussed during this
presentation
Exciting future directions
in emotion research
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Nature-nurture interplay
– Genetic and environmental influences on
emotional responsivity
Summary
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Emotions can be conceptualised as reactions to
reinforcing/punishing (threat) ‘object’ in the
surroundings
Their purpose is to warn us and guide us
– Approach or avoid?
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A large and varied brain circuitry subserves
emotion perception and regulation of emotional
responses
– Emotional disorders as malfunctioning of the circuitry
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The genetic and environmental influences to the
functioning of that circuitry a hot new research
topic