Emotion and Meaning

1. Emotion and Meaning • Chris Rorden • www.mricro.com

2. Temporal lobectomy • Brown and Schäfer (1888) reported behaviour of monkey ‘Tame one’ after bilateral temporal lobectomy. • Preop: wild, fierce • Postop: • Does not retaliate or escape if slapped, tame • Poor memory and intelligence • Evidence of hearing and seeing, but ‘no longer clearly understands meaning of sights, sounds.’ • Does not select raisins from other food in dish: does not seem to visually recognize items.

3. A: Klüver-Bucy Syndrome • Klüver-Bucy (1938) rediscover Brown and Schäfer. • Tameness • Visual Agnosia • Hyperorality (examines objects with mouth) • Compulsive attention to visual stimuli • Hypersexuality • Lack of social skills • Change in diet (eats more meat)

4. B: Klüver-Bucy Syndrome • Is KB syndrome unitary (all symptoms, or none) or do specific focal lesions cause components: • Visual Recognition: Inferior Temporal Cortex Mishkin & Pribham (1954). • Emotion: Damage to just amygdala Weiskrantz (1954)

5. Role of Amygdala • Primate amygdala damage: • Function of amygdala or traversing fibre tracts? • Exitotoxic lesions [destroy cell bodies, spare fibres] suggest amygdala plays role in processing emotion. • For review: Calder et al. (2001).

6. A: Amygdala and social judgement • Adolphs et al. (1998) asked people to judge the ‘approachability’ and ‘trustworthiness’. • Photographed faces: Patients with bilateral amygdala damage gave more positive ratings than controls or patients with unilateral lesions. • Written biographies: Patients showed similar ratings to controls. • Conclusion: words directly evoke information, do not require amygdala. Unfamiliar faces must be matched to prior experiences.

7. B: Results • Judgements of photographs:

8. A: Bechara et al. 1999 • Emotional deficits seen following damage to amygdala and ventromedial frontal damage. • Are these due to the same functional deficits? Or are separate processes involved?

9. B: Amygdala patients • 5 patients with bilateral amygdala damage

10. C: Ventromedial Frontal patients • 5 patients with Ventromedial Frontal lesions.

11. D: Task • Gambling task • Decks A&B disadvantageous: you lose over time • $100 per win, occasional huge losses (e.g. up to $1250) • Net loss • Decks C&D advantageous: you win over time • Only $50 per win, but small losses • More wins than losses • Players must play each deck to discover if it is beneficial or bad.

12. E: Behavioural Results • Controls learn to avoid A & B, both patient groups begin to rely on them (hoping for big win to counter mounting losses).

13. F: Anticipatory SCRs • Skin conductance responses (SCR, lie detector) measure of emotional state. • SCR generated prior to picking a card. • In controls, bigger SCR prior to picking from the ‘high risk’ deck • Patients do not show difference between decks in this anticipatory measure.

14. G:SCRs in response to gain/loss • Controls show strong SCR in response to wins/losses. Big loss when losing with decks A&B leads to amplified SCR. • VMF patients also generate SCR to wins/losses. • Amygdala patients show little SCR.

15. H: Conclusions • Both groups impaired in decision making. • Surprising for amygdala group: they have intact frontal lobes. • Amygdala plays role in generating initial emotional responses. • VMF required to integrate emotional responses and develop winning strategies.

16. A: Clark et al. 2003 • Bechara show Ventromedial frontal patients choose poorly on the Iowa gambling task. • Clark et al examine patients with lateral prefrontal cortex damage

17. B: Results • Controls and Left hemisphere patients learn to avoid disadvantageous decks. • Right patients persist taking more cards from disadvantgeous deck • In figure: negative score means more cards from bad decks than good decks.

18. A: Amygdala and visual processing • Anderson & Phelps (2001) examined visual performance in patient with bilateral amygdala damage. • ‘Attentional Blink’ task: • Asked to report green words presented in a rapidly displayed stream of black words. • Following a target (T1), people tend to miss a second target (T2) unless there is a long delay. • This ‘attentional blink’ is reduced if T2 is an emotionally salient word (like ‘sex’).

19. B: Task • Schematic of ‘attentional blink’ task.

20. C: Results • Controls: (open symbols) • Less attentional blink for negative than neutral words. • Amygdala patient: (filled symbols) • No difference between  negative and  neutral words.

21. D: Conclusions • Patients with right amygdala damage appear similar to controls. • Patients with left damage are similar to bilateral patient. • Suggests amygdala not only involved with memory, but also initial perceptual awareness: • Amygdala ensures important events receive extra processing. • Role in vigilance.

22. A: LeBar and Phelps (1998) • Healthy people show stronger skin conductance responses (SCR, lie detector) to arousing words. • Healthy people also remember arousing words more than neutral words. • Psychological Science (1998), 9, 490-493.

23. B: LeBar and Phelps (1998) • Patients with unilateral temporal lobe damage (including amygdala) show normal SCRs!

24. C: Conclusions • LeBar and Phelps argue that ‘only control subjects exhibited an increase in memory for arousing words over time’ • Is the difference due to emotional nature of words, or shoddy memory in patients? • Right (RTL) patients show control-like pattern of better performance for arousing than control words, though L&P argue they have different patterns of memory decay (Controls remember arousing words, RTL patients forget). • Left (LTL) patients may be at floor performance. • Interaction in controls pretty weak.

25. Human amygdala damage • Humans with amydala damage • Poor face recognition, esp. expression. • Adolphs (1995) small number of patients: • Bilateral damage: poor at fear, anger surprise • Right damage only: no noticeable impairments • Left damage only: poor anger and surprise • Poor memory of emotional material. • Conceptual understanding of fear intact: simply recognition impaired.

26. A: Amygdala’s functional asymmetry • Funayama et al. (1997): • Examine startle response to pictures. • Controls show startle to negative pictures or when they see pictures that they have been told predict bad consequences (e.g. shock) • Compare unilateral amygdala damage to heathy responses • Right temporal lobectomy (RTL) • Left temporal lobectomy (LTL) • All groups verbally rate pictures similarly (they agree that the aversive pictures are less pleasant than the others).

27. B: Results * • Controls: stronger response to negative pictures. • LTL patients similar to controls. • RTL patients do not show this pattern.

28. C: Results 2 • RTL and normals show strong response when image appears that they have been told signals possible electric shock. • LTL patients do not show this response. <- SP is a bilateral patient

29. D: Conclusion • RTL modulates fear response to intrinsically aversive images. • LTL modulates fear that results from linguistic/cognitive representation. • Aversive nature learned through verbal instruction.

30. Disgust • Emotion of disgust appears related with the sensation of taste. • Insula and Basal Ganglia: • Stimulation causes nausea and unpleasant tastes • Lesions inhibit learned taste aversions

31. Disgust • Calder et al.(2000) describe patient NK: • Left lesion includes Insula and BG • Impaired recognition of disgust.

32. Delusional Misidentification Syndromes • 3 DMS: • Pick [1903] “reduplicative paramnesia” • Misidentifies familiar places as replica • Capgras Syndrome [1923] • Familiar people described as doppelgangers • visual but not emotional recognition • Frégoli Syndrome [1927] • Person misidentified as someone else with totally different appearance. • DMS are rare • Rare enough to be of little clinical importance • Yet, may still reveal how emotions are processed

33. Hirstein and Ramachandran [1997] • H&R postulate that DMS is caused by disconnection between visual recognition system and emotional system. • E.G. Capgras syndrome due to disconnection between fusiform gyrus [face area] and amygdala [limbic system]

34. Hudson and Grace • 71 women suffered lesion to anterior fusiform gyrus (between face area and amygdala) • Frégoli Syndrome • Identified husband as elder sister (who had died 3 years previously) • Only visual misidentification (fine on phone) • Home was ‘replica’ would pack bags to return to ‘real’ home. • Support for H&R

35. Pain asymbolia • Patient’s report they can feel pain, but it no longer hurts. • Ramachandran (1998): speculates disconnection of insula from cingulate (part of limbic system) • Insula identifies pain • Cingulate does not receive signal, so discounts threat

36. Emotion and cognition • James: emotion is the brain’s response to bodies reaction. Stimulus (bump in night) -> Arousal (heart races) -> Emotion (fear) • Canon: Stimulus (bump in night) + Emotion (fear) -> Arousal (heart races) • Schachter’s Two-Factor Theory (1962) Stimulus (bump in night) -> Arousal (heart races) + Cognitive Label (‘I’m afraid’)-> Emotion (fear) • secrectly give people adrenaline and they report heightened emotional state. Funny events seem funnier, frustrating events seem more frustrating.

37. Emotion and cognition • Kolb suggests emotionality decreases after spinal cord injury. Degree of change dependent on amount of cord severed. • This is not a well-replicated finding. See Nicotra (2006) for review, Cobos et al (2002)