Brain And Emotion Flashcards
Brian systems
Prefrontal cortex (hemispheric differences) - Dorsolateral, ventromedial, orbirofrontal
Subcortical structures
- Limbic system, nucleus accumbens, amygdala
Posterior RH
- Perception of expressions
PFC: Emotion memory and recall
Phobics given pictures of aversive stimuli
Results in PFC activation; seems to be location of recall of emotion memories
Emotions are essential for motivation and planning. Need an emotional memory and the PFC seems to be the location of emotional working memory
PFC Hemispheric differences
Davidson emotional films
- Left anterior activated during positive affect - right anterior during negative affect
Sutton et al (1997): Pictures: induced changes in mood
PET scan. Right side increase during negative affect
Left side increase during positive affect and left nucleus accumbens
‘Socially wary’ children more right prefrontal activation (Davidson 2001)
Amygdala - Substantial evidence has an important role in the:
Perception of fear
Feelings of fear
Learning to recognise fear and aversive events (associative aversive learning)
Breiter et al (1996)
The amygdala is activated by perception of fear in the face of another
Morris et al (1996)
Activation in the lef amygdala showed a linear relationship with decreasing intensity of happiness and increasing intensity of fear
Amygala
Stimulating amygdala in animals produces freezing and fear response
Stimulation and seizures focused on the human amygdala frequently produce fear or other emotional responses (Gloor, 1990)
Kluver and Bucy (1937)
Lesion to medial temporal lobe:
Animals placid - lacking emotion
Will approach fear inducing stimuli with no display of anger or fear
Inappropriate sexual behaviour: mounting inanimate objects
Weiskrantz (1956) demonstrated that it was the amygdala within the medial temporal lobe
Klüver-Bucy syndrome
Lesions of amygdala and surround
emotional blunting: displays a flat affect and may not respond appropriately to stimuli
Hyperphagia: extreme weight gain, oral stimulation or exploration and not feeling hungry
Inappropriate sexual behaviour: may be an increase in their sexual activity
Visual agnosia: an inability to visually recognise objects
Urbach-Wiethe Syndrome
Rare
SM
progressive calcification of the amygdala. A few early memories of fear but no fear in adulthood
Is emotional - has other emotions
Personal space .34 metres (Kennedy, 2009)
Amygdala helps create personal space
Is fascinated by sights that terrify others eg haunted house
Exotic pets (spiders, snakes)
Recent SM findings
Tsuchiya et al (2009)
briefly presented fear expressions or fear scenes
Button response - choose which was most fearful. normal response
unlimited time - abnormal response
Kennedy and Adolphs (2011) gaze to eyes improved performance
Interpretation
Initial subconscious detection occurs in other regions and is accurate
Then amygdala directed to gather further evidence eg form eyes to assess the danger
non conscious processes may cause arousal but lack of amygdala prevents correct interpretation
Amygdala and individual differences
- Big individual differences in quality and intensity of amygdala response (blood flow, glucose use) to same stimuli
- Depressed patients with more severe depression had greater blood flow in amygdala (Drevets, 1995)
- Higher dispositional negative affect - higher glucose metabolism
Amygdala questions
Affect in general, negative affect in particular or fear most specifically? (Davidson and Irwin, 1999)
Where is happiness?
Left, Right or both sides equally involved in fear