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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

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res

pons

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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