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Biopsychology of Emotion

Biopsychology of Emotion. Ch. 17. Outline. Early Research on the Biopsychology of Emotion Emotions and the Autonomic Nervous System Human Facial Expressions of Emotion Fear Conditioning Brain Mechanisms of Human Emotion. Early Research.

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Biopsychology of Emotion

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  1. Biopsychology of Emotion Ch. 17

  2. Outline • Early Research on the Biopsychology of Emotion • Emotions and the Autonomic Nervous System • Human Facial Expressions of Emotion • Fear Conditioning • Brain Mechanisms of Human Emotion

  3. Early Research • Darwin’s The Expression of Emotions in Man and Animals was the first major event in the study of the biological bases of emotion • Darwin believed emotions evolved from behaviors that indicated what an animal would do next in a given situation; that when these behaviors were advantageous to the animal

  4. Early Research • The James-Lange Theory was the first attempt to explain the physiological bases of emotion; suggests that emotion-inducing stimuli are received and interpreted by the brain, which triggers visceral changes ( organ changes in the abdomen or thorax) that subsequently trigger the experience of emotion

  5. Early Research • Canon-Bard Theory is alternative theory based on the idea that emotional stimuli evoke visceral and emotional responses that are independent of one another

  6. Early Research • Neither theory is entirely correct; emotions can be induced by stimuli that cannot elicit a peripheral, visceral response (e.g., patients suffering from a spinal cord transection), but visceral responses can often induce an emotional state in the absence of any obvious eliciting stimuli (e.g., a racing heartbeat and increased respiration can produce a feeling of fear in the absence of an eliciting stimuli)

  7. Early Research • Bard reported that decorticate cats (without cortex) responded with unusual aggression to the slightest provocation; often this behavior was not directed at any specific topic. • Bard concluded that the hypothalamus is critical for the performance of these aggressive behaviors, which he called sham rage; he also believed that the cortex normally inhibited and directed these aggressive displays

  8. Early Research • This theory of hypothalamic function was followed by Papez’s proposal of a limbic system that controlled the expression of emotions by connections with the hypothalamus and mediated the perception of emotions by connections with the cortex • This was supported by Kluver-Bucy syndrome - damage to the amygdala (part of the limbic system) resulting patients who are fearless, hypersexual, and inclined to explore objects with mouth

  9. Emotions and the ANS • A large body of research has focused on the degree to which specific patterns of ANS activity are associated with specific emotions; both the J-L (multitude of activity patterns, each generating a unique emotion and C-B (single general pattern of activation) theories are partially correct

  10. Emotions and the ANS • In addition, the effectiveness of ANS measures in polgraphy has been studied; these tests examine changes in emotions as indexed by ANS activity to assess truthfulness

  11. Emotions and the ANS • Many of these studies employ a control-question technique -ANS responses to answers to innocuous questions (Is your mother’s name Betty?) are compared to those of target questions (Did you steal the money?)

  12. Emotions and the ANS • However, most normal people will react strongly to the target question, even if they are not guilty, which makes it difficult for investigators to tell if they are lying • To circumvent this possibility, guilty-knowledge technique is used

  13. Emotions and the ANS • Guilty knowledge technique - polygrapher asks a series of questions that contain possible details of the crime • Only some details are true; a subject’s responses to true details (only a guilty suspect would know) are compared to false details (that would make innocent parties equally uneasy)

  14. Human FacialExpressions of Emotion

  15. The Primary Facial Expressions • Ekman and Friesen analyzed hundreds of films and photos of people experiencing various emotions • They concluded that there are six primary facial expressions of emotions and all others are mixtures of these

  16. The Primary Facial Expressions • The six primary facial expressions are: • anger • fear • happiness • surprise • sadness • disgust

  17. The Primary Facial Expressions • Facial expressions are universal: • when asked to view photos of people who were asked to contract specific facial muscles, the 12 different cultures that were tested linked the same emotions to the facial expressions • isolated New Guinea tribe members could correctly identify facial expressions and vice versa

  18. Deceptive Facial Expressions • It is difficult to fool an expert because microexpressions of genuine emotion often break through the false one • For example, genuine smiles(Duchenne smiles) involve contraction of both the zygomaticus major and the orbicularis oculi, whereas false only involve the zygomaticus major • EMG recordings can also detect emotional changes even when the motor output to the facial muscles is too slight to change them

  19. Fear Conditioning • Fear conditioning is the establishment of fear in response to a previously neutral stimulus like a tone (CS) by pairing it with the presentation of an aversive stimulus like a footshock (US) • There are neural substrates for this form of auditory fear conditioning

  20. The Amygdala and Fear Conditioning • Lesions to the medial geniculate nucleus of the thalamus block fear conditioning, but lesions to the primary auditory cortex did not • Suggested that MGN projected to an alternate neural structure that was involved in fear - amygdala, which, when lesioned, also blocks fear conditioning

  21. The Hippocampus and Contextual Fear Conditioning • The context or environment in which fear-inducing stimuli are encountered can also come to elicit fear; this is called contextual fear conditioning

  22. The Hippocampus and Contextual Fear Conditioning • Given the role of the hippocampus in spatial memory, it is not surprising that this brain structure is involved; lesioning the hippocampus blocks the development of contextual fear conditioning without blocking conditioning to CS

  23. Brain Mechanisms ofHuman Emotion

  24. Specific Brain RegionsHave Specific Roles • This research focuses on brain-damaged patients and functional imaging studies of healthy patients • Have confirmed the role of the amygdala and prefrontal cortex in human emotion and failed to support the limbic theory

  25. Specific Brain RegionsHave Specific Roles • Researchers have found that brain regions involved with one emotion are not necessarily involved in another… and that brain region might be involved in one aspect of an emotion but not another aspect of the same emotion

  26. Specific Brain RegionsHave Specific Roles • Example: the amygdala appears to be very involved in the perception (as opposed to the expression) of fear… lesioning the amygdala leaves a person unable to perceive fearful emotions from others, although these patients have no problems matching the appropriate emotion with a sentence or in expressing various emotions using facial expression upon request

  27. Specific Brain RegionsHave Specific Roles • A similar deficit is seen in patients with Urback-Wiethe disease, in which the tissue forming the amygdala and medial temporal lobes is calcified and destroyed • fMRI has revealed the lateral aspects of the frontal lobes as most associated with positive emotions, whereas the medial aspects of the frontal lobes are most associated with negative emotion

  28. The Right Hemisphere is More Involved in Human Emotion • Studies involving brain damaged patients and functional imaging techniques have both revealed that, in general, the right hemisphere tends to play a greater role in emotional behaviors; however, this depends on the structure under consideration and the particular aspect of emotion under study

  29. The Right Hemisphere is More Involved in Human Emotion • The RH is more involved in perception of emotion, specifically facial expression and prosody (melody of speech that conveys sincerity, sarcasm, etc.)

  30. The Right Hemisphere is More Involved in Human Emotion • Although lesions of the right and left frontal lobes equally disrupt perception of emotion from facial features, lesions of the right, but not left, temporal lobe disrupt it

  31. The Right Hemisphere is More Involved in Human Emotion • By contrast, PET studies indicated that the right amygdala and prefrontal cortex are more active in prosody, whereas the right temporal lobe is less responsive than the left

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