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Psy393: Cognitive Neuroscience
Prof. AndersonDepartment of Psychology
Emotion
OverviewTheories of emotion
Subcortical contributionsAmygdala: Nonhuman animalsAmygdala: Humans
Cortical contributionsPrefrontal cortexHemispheric asymmetries
EmotionWhat is it?
Central to human experienceOwn understanding notoriously poor
Why? No privileged access to how brain creates emotionsCognitive neuroscience: Look to brain for its organization
Emotion: Its complex!Not a single thing
FeelingsThoughtsSocial signals
Expression (face, body, voice)Recognition (face, body, voice)
MemoriesPerceptionAttention (external and internal)
Emotion: Fundamental concepts
Basic emotionsIs their a basic palette of emotions?
Afraid, angry, disgusted, happy, sad, surprisedNot so basic
Ashamed, bored, infatuated, sexy, in love?
Emotional dimensionsEmotions are not discreteActivation along 2 or more
dimensionsArousal (low to high)Valence (pleasant vs. unpleasant)Approach/avoidance
Psychological theories of emotion
Is emotion in the body or the brain?Starts w/ body
James-Lange (1890)Requires emotion specific physiological signatures
Starts w/ brainCannon-Bard (1927)
Autonomic response too slowEvidence from spinal cord injuries
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Psychological theories of emotion
Relation between cognition and emotion
Thinking and feelingRole of appraisal
Schacter-Singer (1962)Thinking determines feeling
ZajoncFeeling independent of thinkingPreferences need no inferences
Thinking and feeling: What can the brain tell us?
Are there separate thinking and feeling parts of the brain? Is there an emotional brain?
Thinking: CortexFeeling: Subcortex
Human emotion: Battle of the brainsArises out of dynamic interactions between cortical and subcortical regions
The Triune Brain: 3 Brains in 1(Maclean, 1949)
Proposed evolutionary brain organizationSegregation of emotion (older) &
cognition (newer)
Cognition: Neomammalian
Motivation/Emotion: Paleomammalian
Motor functions: Reptilian
– Neocortex greater expansion across species– Limbic system size evolutionarily conserved– Suggests, emotional functions evolutionarily conserved
The limbic system: Emotion specific?
Problem: Not all structures associated with emotion (e.g. hippocampus)
Subcortical contributions to emotion: The amygdala
• Anterior temp lobe/ ant. to hippocampus
• Multiple nuclei
• Widespread connections: Cortex to brainstem
Anterior temporal lobe: Intrinsic fear responses
Indirect implication of amygdala in emotion
Kluver-Bucy Syndrome (1939)Emotional blunting/TamenessLoss of neophobia (people, objects) HyperoralityAltered sexuality“Psychic blindness”
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Selective amygdala lesions: Rodents
Cute & Cuddly or fearsome predator?
• Direct implication of amygdala in emotional behaviours (Blanchard & Blanchard,1972)
Selective amygdala lesions: Nonhuman primates
Rhesus monkeysLesioned @ 2 wksReturned to mothersTested @ 6-8 months
1) Loss of neophobia2) Loss of snake fear
Prather et al. (2001)
Intact Lesion
1 2In presence of snake
The monkey split brain: fearful & fearless
1) Sever cross hemisphere projections
2) Lesion amygdala unilaterallyL eye (lesioned)fearless
R eye (intact)fearful
X
Fearless Fearful
Downer et al., 1961
Amygdala and social fitness: Primate social structure
Dominance hierarchies
In the lab Rosvold et al. (1954)
Established hierarchyLesion dominant maleFall to subordinate status
In the wild Kling et al. (1970)
Lesion and returned to wildSocial rejection Early death w/out social support
Loss of threat appreciation impairs social fitness
Acquired fear: Fear conditioning
• Most feared events are learned
• Lower through higher animals have fearl learning mechanism
Fear conditioning
CS: conditioned stimulus
US: unconditioned stimulus
CR: conditioned response
UR: unconditioned response
CRUR
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Does CS evoke fear state?Do rats feel fear in the presence of the CS?
Fear potentiated startle100 db tone: startleCS & tone: greater startle
Resembles human startleLight/dark alleyLoud noise
Fear conditioning & the amygdala:
Its all in the wiring• Convergence of CS and US • Orchestrates complex fear response: CR
• Behavioral, autonomic, and endocrine activation
Fear conditioning depends on the amygdala
CS & US convergence
Lesion amygdalaIntact URImpaired CR
Lesion cortexIntact UR & CR
Lesions response systems
Impair both CR & UR
CS input
US input
CR/UR
Amygdala Lesions in Humans(Urbach-Wiethe Disease)
Examine importance for:
• Conditioned fear
• Emotional modulation of episodic memory
• Comprehension of social signals
Human amygdala: Fear conditioning
CNTRLS (A+H+)
A-H+
A+H-
A-H-
CS: Colored squareUS: 100db toneUR/CR
Skin conductance (SCR)
Amygdala lesion (A-)Intact URImpaired CR
Hippocampal Lesion (H-)Intact UR & CR
Fear conditioning: Distinct roles of amygdala and
hippocampusAmygdala lesion
Impaired autonomicIntact declarative
HippocampalIntact autonomicImpaired declarative
A: ImplicitH: Explicit
Claparede (early 1900s)
CNTRLS (A+H+)
A-H+
A+H-
A-H-
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Emotional enhancement of recollective experience
Human emotional memory is not limited to fear conditioning
Unconscious automatic learning
Emotion can influence recollectionConscious retrieval of past experiences
Emotion enhances retrieval of past experiences
Is the amygdala responsible for this enhancement?
Human amygdala: Emotional influences on recollection
Amygdala lesions
• View story with emotionally significant middle section
• Test recall 1-week later
• Intact emotional reactions
• No enhanced memory
Hippocampal lesions (w/ intact amygdala)
• Impaired overall memory
• Preserved enhancement of emotional events
Controls
Patient
Cahill et al., 1995
Hamann et al, 1996
Human amygdala: Role in evaluating facial expression
6 Basic emotionsCross-culturally recognized
1 2 3
4 5 6
Intact face recognitionImpairment selective for fear
Human amygdala: Impaired recognition of fear
Adolphs et al (1994)
Functional magnetic resonance imaging• Patients w/ congenital disorder of amygdala: Can we Generalize?
• Look at amygdala function in healthy individuals
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Fear conditioning: fMRI
Is the human amygdala activated during fear conditioning?
• Neutral faces paired with noise burst (CS+)
• Unpaired faces (CS-)
Buchel et al., 1998
Amygdala: CS+ > CS-
Emotional enhancement of recollective experience: fMRIIs amygdala activation during viewing correlated with later enhanced memory?
Amygdala and memoryAmygdala
Hippocampus
Hamann et al., 1996
• Individual differences in amygdala activity predict memory
• Enhanced memory for + and - events (arousal not valence)
• Correlation: amygdala and hippocampus for emotional events
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L R
Functional imaging: Event-related fMRI
Time Bin1 2 3 4 5 6 7 8 9 10 11
-1.25
-0.75
-0.25
0.25
0.75
1.25A
myg
dala
res
pons
e
0123
StimulusPresentation
Period
Amygdala response during viewing
Canli et al., 2001
• Examine amygdala response on a event by event basis w/in a subject
Predicts what an individual will remember
Amygdala response to fear expressions: fMRI
Morphing continuum
Happy —> Fear
Morris et al, 1996
Human emotional unconscious
Is all emotional processing conscious?
Cortex (conscious?)
Amygdala (unconscious?)
Is amygdala processing independent of awareness?Is amygdala processing independent of cortex?
High and low roads to the amygdala
High roadCortico-amygdalaSlowerconscious
Low roadThalamo-amygdalaFasterunconscious
Bi-directional interactions
Human emotional unconscious: Evidence from face recognition
Prosopagnosia: Emotion w/out awarenessImpaired identityIntact SCR
Capgras Delusion: Awareness w/out emotion
Intact identityImpaired SCR
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Amygdala: Unconscious fear conditioning
CS+ CS-
Morris et al., 1998
CS+ Mask
CS- Mask
• Amygdala conditioned responses independent of subjective awareness
Cortical blindness: Fear blindsight
XMorris et al., 2001
• Does amygdala response depend on cortex?
• Examine patient w/ cortical blindness
• Examine amygdala response in the absence of cortex/awareness
L R
Intact/Seen Lesion/Blind
Cortical blindness: Fear blindsight
• Stimuli presented to intact and blind hemifield
Intact Blind
Cortical blindness: Fear blindsight
• Amygdala discrimination of fear in blind field• Depends on subcortical thalamo-amygdala pathway
Amygdala can influence perceptual awareness:
Vigilance
Control-NegativePatient-NegativeControl-NeutralPatient-Neutral
• Normal subjects show enhanced awareness of emotional events (decreased attentional blink for emotional words)
• Patients with amygdala lesions don’t
• Amygdala enhances cortical perceptual processes: Shapes perception
Is the amygdala necessary for normal emotional
experience?Evaluation Expression
Impaired Intact
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The human amygdala: Overview
Fear conditioningEvaluation of socio-emotive signalsEmotional unconsciousEmotional influences on episodic memory and perceptual awarenessEmotional experience?
If not the amygdala, where then?
Cortical contributions to emotion:
Prefrontal corticesIn contrast with the core limbic system
Prefrontal cortex has undergone greatest expansion across phyla
Cognitive
Affective
Lesions of the ventromedial prefrontal cortex
Don’t show autonomic response to emotional pictures
Prefrontal contributions to emotional experience: Laterality
Lesion studiesLeft: Catastrophic reactionsRight: Euphoric-indifference
EEG in adultsLeft: positive/approachRight: negative/avoidance
EEG asymmetries in infants predict separation distress
Greater left Right EEG associated with cryingAffective Style (Davidson): Left/right prefrontal asymmetries may be related to affective predispositions
OFC: Social control of behaviour
Lesions of OFCMimicryUtilization behaviour
Environmental dependencyWithout OFC we become stimulus driven animals
Antisocial behaviouracquired sociopathy
Non-premeditated murderersDecreased OFC activation
OFC maybe related to morals
Emotional influences on decision making
Orbitofrontal cortex (OFC) allows emotional control of decision makingOFC patients
Risky decisionNo anticipatory SCR response
No “somatic markers”
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OFC and reward/punishmentOFC patients can learn when something is rewarding/punishingHave difficulty in reversal learning
Changing of reward contingenciesPunishment vs. reward
OFC necessary for flexibility in emotional responseSensitivity to context
Laughing out loud at a funeral
PFC: Affective disordersDepression
Associated with hyperactive PFC
SchizophreniaAssociated with hypoactive PFC
History of psychosurgeryNot successful for SchizophreniaSomewhat for depression
The End