1 emotion lecture 9 march 21 st, 2006. 2 cognition & emotion in the past, cognition has been...

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Emotion

Lecture 9March 21st, 2006

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Cognition & Emotion

• In the past, cognition has been viewed as something separate from emotion

• Philosophers (e.g., Descartes) thought that rationality should be free of emotion

• We will see today that we actually need emotion to act rationally

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What is emotion?

• Emotion – state of mental excitement characterized by alteration of feeling tone and by physiological and behavioral changes

• Neuropsychologists view emotion not as a thing, but rather as an inferred behavioral state called affect

• Affect – is a conscious subjective feeling about a stimulus independent of where or what it is. Affective behavior is internal and subjective

• Controversy:• Does emotion have to be conscious?• Is a physiological response necessary?

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There are many components of emotion

1. Physiology – central and autonomic nervous system activity and the resulting changes in neurohormonal and visceral activity (heart rate, blood pressure, perspiration etc.)

2. Distinctive motor behavior – facial expressions, tone of voice, and posture express emotional states (might be different from observed verbal behavior).

3. Self-reported cognition – self reported rankings (feeling of love or hate etc.)

4. Unconscious behavior – cognitive processes influence behavior that is not conscious – behavior of which we are not aware (see Gambling Task later on)

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James vs. Cannon Theory of Emotion

• William James “bodily changes follow directly the perception of the exciting fact, and our feelings of the same changes as they occur is the emotion”

• Stimulus (bang!) Perception/interpretation of (danger) Specific pattern of autonomic arousal (e.g., heart races, etc.) Particular emotion experienced (fear)

• This would suggest that there are specific body reactions to different stimuli problematic for the theory

• Walter Cannon emotions can be experienced without the perception of bodily changes

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• If there is a reduction in the bodily reaction to a stimulus then there should be a reduction in the intensity of emotions

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Stanley Schacter – Two-factor theory

• Two-factor theory – the idea that emotional experience is the outcome of physiological arousal and the attribution of a cause for that arousal

• Study: subjects injected with epinephrine (adrenaline) based on the context (angry vs. happy confederate) reported different emotions

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• Levenson, Eckman & Friesen (1990) found that different emotions do have different physiological signatures

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Are emotions learned?

• If emotions are learned, what could we expect to see around the world regarding emotions?

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Brain and Emotion

• Emotion is not a unitary construct

• Different brain regions process different aspects of emotion

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History of Emotion in the Brain

• James Papez, 1937• Emotion circuit – hypothalamus, anterior

thalamus, cingulate and hippocampus• Limbic structures act on the hypothalamus

to produce emotional states• Cortex played no role in emotion• Gained instant approval in the heyday of

Freudian thinking• Paul MacLean later named these

structures the “Papez circuit”.• He added the amygdala and orbitofrontal

cortex and named the system – the limbic system

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Brain and Emotion

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Limbic System

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Amygdala

• Kluver-Bucy syndrome caused by temporal lesions – lack of fear, hypersexuality, ingestion of non-edible items

• Individuals with amygdala damage have difficulty identifying fearful facial expressions

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Amygdala: Fear Conditioning

• CS + UCS Conditioned response

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Amygdala

• Joseph LeDoux – two pathways to the amygdala

• Quick route: thalamus amygdala

• Slower route: cortex amygdala

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Hippocampus: Emotion and Context

• Hippocampal lesions impair contextual fear conditioning

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Hypothalamus

• Hypothalamic-Pituitary-Adrenal (HPA) axis

• Hypothalamus (CRF) Pituitary (ACTH) Adrenal gland (cortisol)

• Autonomic changes (heart rate etc.)

• Flight or fight

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Anterior Cingulate

• Lesions of the anterior cingulate cortex have been associated with changes in emotion

• Apathy, inattention, emotional liability and changes in personality

• Pain perception

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Orbitofrontal Cortex (OFC)

• Phineas Gage• Change in personality

and emotionality• Irresponsibility, lack for

concern for for the present or future

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• Choosing how to act does not simply require discrimination between incoming stimuli

• When choosing how to act, we must integrate incoming stimuli with our values, current goals, emotional state and social situation

• The OFC is important for processing, evaluating and filtering social and emotional information

• Damage to OFC impairs the ability to make decisions that require feedback from social and emotional cues

Orbitofrontal Cortex & Decision Making

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Social Decision Making

• The prefrontal cortex plays a critical role in how we select among a multitude of information

• Social context is one of the criteria for the selection of an action (what is socially appropriate)

• Individuals with damage to the OFC show deficits in social decision making

• Their responses are overly dependent on perceptual information (what is directly in front of them) while they ignore social cues

• In other situations they appear to be insensitive to social norms or goals

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Orbitofrontal Cortex and Aggression

• Individuals with damage to the OFC show inappropriate response and may show inappropriate aggressive responses

• PET studies show that individuals with with violent and antisocial histories show reduce metabolism in the OFC

• Some OFC damaged patients are prone to exhibit antisocial behaviors, such as stealing or violent outbursts

• “acquired sociopathy”

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• Patient J.S. – suffered a head trauma that resulted in bilateral damage to the OFC along with some damage to the left amygdala

• During his hospital stay he assaulted and wounded a member of staff, threw objects and furniture at people and was aggressive towards other patients

• When tested he showed severe impairment at processing social stimuli, such as facial expressions and interpreting emotional reactions in other individuals

Orbitofrontal Cortex and Aggression

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• How is the OFC specialized at processing emotional feedback?• Edmund Rolls suggests that OFC is necessary for on-line, rapid

evaluation of stimulus-reinforcement associations• Learning to link a stimulus and action with its reinforcing properties • Reinforcing properties change rapidly• It may be appropriate to laugh loudly at a friend’s joke at a party• However, it is not appropriate to laugh loudly if the friend whispers you

a joke during a lecture• The appropriate and rewarding response to hearing a joke changes

depending on the social context

Orbitofrontal Cortex and Emotional Decision Making

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• Reversal learning is an example of rapidly changing reinforcement properties

• Subjects are told that they can earn point by touching one stimulus when it appears on a video monitor

• At the same time they have to withhold a response when different stimulus appears, or they lose a point

• After subject learn this, stimulus-reinforcement contingencies are unexpectedly reversed

• OFC patients are able to do the first part of the task but they are impaired in reversal learning

Orbitofrontal Cortex and Emotional Decision Making

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• Antonio Damasio• Emotion influences everyday “rational” decision

making• Emotion and cognition are not separate• Emotional evaluation guides reasoning • “gut feeling”• Somatic marker – a emotional response mechanism

that helps sort through options. It provides a common metric for evaluating options with respect to their potential benefit

• Somatic marker OFC

Orbitofrontal Cortex and Emotional Decision Making

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OFC and Somatic Marker

• Paradoxical behavior of patients with lesions of the OFC – the representations required to guide and produce an action are brought into working memory, but they are striped of emotional content

• A patient may still mull over problems, albeit in an impersonal manner

• A patient may be aware of the death of a close relative and understand the finality of it, but he is divested of the emotional pain that accompanies the loss

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OFC and Emotion

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Bechara et al (1997)

• OFC is important for emotional responding

• Are emotional responses necessary for appropriate decision making? Gambling task that simulates real-life decision making

• $ 2,000 loan• Drawing of cards• Decks A & B are

disadvantageous • Decks C & D are advantageous • Measuring SCR

Decks C & D

C & D C & D

Decks A & B

A & B A & B

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Bechara et al (1997)

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Hemispheric Asymmetries in Emotional Processing

• Left frontal damage catastrophic reaction – patients seem emotionally volatile and prone to sad moods and tearfulness

• Right frontal damage euphoric-indifference reaction – patients seem inappropriately cheerful, prone to laughter and lack of awareness

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Comprehending Emotion - Prosody

• Affective prosody – emotional context or tone of an utterance• “My mother is coming to dinner”• Propositional prosody – communicates lexical or semantic information• “What’s that in the road ahead?”• “What’s that in the road, a head?”• Patients with damage to right parietal damage are impaired in

comprehending prosody• Aprosidia – difficulty in producing prosody• Tests: patients are asked to repeat sentences in different tones of voice

(e.g., happy, sad, angry or indifferent)• Lateralization of prosody is subject of controversy

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Facial Expressions

• Patients with right hemisphare damage are deficient in discriminating facial expressions

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Facial Expressions

• Two methods of studying facial expressions

• Patients with left or right hemisphere damage are photographed

• In neurologically intact patients facial expressions, on the right-and left-hand sided, are studied