Emotion 2 - Neural Mechanisms of Emotion Flashcards
What evidence is there for the hypothesis that emotion is a product of the brain?
- Phineas Gage (Damasio, 1994)
- Kluiver-Bucy (1939)experiments, different lobes removed from monkeys. Monkeys without temporal lobes became emotionally dulled.
- Weiskrantz, lesions to the amygdala reduced emotionality.
Why would the amygdala not be the central component behind emotion response?
Rats whose amygdalae were stimulated did not all show fear responses. So something other than amygdala mediating emotion.
What did monkeys show when their amygdalae were damaged?
- Reduced emotionality (Kluiver-Bucy syndrome)
- Ceased neophobic responses - no longer showed fear/apprehension towards new objects.
Which brain area is implicated in social reward in humans?
ventromedial prefrontal cortex. (Davey et al., 2010)
Describe what occurred to and what was found from research into Patient S.M.
Had a rare condition, Urbache-Wiethe disease, which caused degeneration of the amygdala. Patient displayed a lack of fear behaviours and reported not feeling afraid.
What did Japanese researchers find about what is remembered during earthquakes?
By correlating the extent of damage to the amygdala with the amount remembered, they found that the more amygdala damage, the less that could be remembered. This suggests that the amygdala may also play a role in cognitive aspects of the peripheral response.
Is the amygdala only implicated in fear responses?
No, shown to be active when shown food or sexual imagery.
When is trait anxiety more likely to develop?
When PPS have less white matter (axonal tracts) connecting the prefrontal cortex to the amygdala, as the PFC typically inhibits the activity of the amygdala.
What is the periaqueductal grey implicated in?
Freezing and avoidance behaviours.
What makes the amygdala well placed to co-ordinate emotional responses?
The amygdala receives sensory input from all modalities.
And it projects to a number of regions downstream which are lonked to emotional responses, such as the hypothalamus, ventral tegmental area and PAG.
What causational research has been conducted in monkeys that implicates the amygdala in emotional responses?
Reis and Oliphant, (1964) observed increased heart rate in monkeys when their amygdalae were stimulated.
What causational research has been conducted in rats that implicates the amygdala in emotional responses
Iwata et al., (1987) showed that rats’ heart rate and blood pressure increased when their amygdalae were stimulated.
Who found increased emotional responses after stimulation to the amygdala in humans?
Halgren et al, (1978)
Who replicated the findings of the Kluiver Bucy experiments and how did they do so?
Weiskrantz (1956) inflicted lesions on the bilateral amygdalae in monkeys.
It was also found that monkeys had marked reductions in avoidance and suppression behaviours compared to controls
What did LeDoux test and what did he find?
Inflicted lesions on different areas of the brain in moneys. Found that damage to the auditory midbrain and auditory thalamus caused impairments in fear conditioning. Suggests that the auditory thalamus sends information to the amygdala.
