Emotion 1 Flashcards
what are emotions?
- states elicited by rewarding or aversive stimuli (S+ or S-) and their omission (-) or termination (!)
- these are states compromise thoughts (“feelings”) and physiological behavioural responses to emotional (i.e., rewarding or aversive) stimuli.
why have physiological/behavioural responses to aversive and positive stimuli been preserved throughout evolution?
- as they have fundamental survival value
- often similar in different animals including humans
- principle organisation of the brain is very similar along all mammalian species
what are the advantages of using a rat as a model system?
- easy to breed and keep
- well-established behavioural tests
- brain large enough to apply selective manipulations to distinct brain structures and brain anatomy very well characterized
what are the disadvantages of using rats as a model system?
- genetic manipulations (used to be) difficult (alternative:mouse)
what are the key milestone studies for the hippocampus, amygdala and hypothalamus?
- Papez theory of emotion (1937)
- Kluver and Bucy’s description of temporal love lesion effects in monkeys (1939)
- MacLean’s limbic system theory (1949)
what are the key milestone studies for the prefrontal cortex?
- Case of Phineas Gage described by Harlow (1868)
- Nauta (1971): Frontal lobes and interoception
what are the key milestone studies for Meso-corticolimbic dopamine system?
- Olds and Milner (1954): Brain stimulation induced reward
- Wise et al., (1978): Neuroleptoc-induced anhedonia
when fear and anxiety compromise protective/defensive responses what stimuli is normally elicited?
aversive stimuli
what does fear refer to?
phasic escape or avoidance responses to distinct aversive stimuli
what does anxiety refer to?
a tonic response to diffuse aversive situation and is associated with conflict and uncertainty
what are some fear and anxiety related disorders in humans?
- generalised anxiety disorder
- obsessive compulsive disorder (OCD)
- panic disorder
- phobias
- post-traumatic stress disorder (PTSD)
conditioned fear and the amygdala
- classical fear conditioning
- functional-anatomical model of conditioned fear: central role for the amygdala
what is the amygdala and its divisions?
- the amygdala is a subcortical structure
- lateral amygdala: input region of the amygdala, e.g. receives auditory input from the auditory area of the brain and somatosensory input from the somatosensory cortex. Plasticity can occur in th amygdala which is why we can become scared of things when they have negative associations
- central amygdala: produces the fear responses such as freezing, blood pressure changes and hormone changes
what are some examples of fear responses?
- defensive behaviour
- autonomic arousal
- hypoalgesia
- reflex potentiation
- stress hormones
Requirement of lateral and central amygdala in conditioned fear, Amorapanth et al. (2000)
- measured lesions in different amygdala nuclei before conditioning
- then subjected them to far conditioning and found that animals with lesions in the lateral and central amygdala has a higher potential for freezing in response to fear