Lecture 11- Neuroscience of emotion I Flashcards
What is the paradox of emotions?
“The paradox of emotions is that, on the one hand, they seem self-evident and obvious when examined introspectively;
on the other hand, they have been extremely difficult to define in objective scientific terms.”
Has a consensus on a definition of emotion been reached?
“Attempts to achieve a consensus definition across the fields from neuroscience to psychology to philosophy have repeatedly failed”
-emotions can drive how the body operates
What is an emotion?
- An emotion constitutes an internal, central (as in central nervous system) state, which is triggered by specific stimuli (extrinsic or intrinsic to the organism)
- what defines the state is that it is triggered by specific stimuli
- emotional stimuli trigger emotional responses
- we usually connect emotion with the outward appearance of it
What is the traditional behaviourist view on emotion?
- have emotional stimuli and get behaviour and other responses that are outwards
- and in humans have additional feature that is subjective feeling
What is the new view on emotion?
- have emotional stimulus and get outward behaviour and other responses this is underlined with central emotion state and in humans have subjective feelings
- the central emotion state is the circuits in the brain producing the feeling and responses
- Humans show unique species typical behaviours and subjective feelings
- However, underlying states with certain fundamental properties are shared across emotions and across species (from humans to flies)
What did Darwin do on emotion?
- wrote a book on expression of emotions in animals and humans
- Identified examples of human emotional expression that are easily recognised in other primates, and domestic animals
- link between subjective feeling and the outward expression
PIC1What was the idea on emotion put forward by William James?
- it is the physical response from the body that makes you afraid
- so the physical state is then triggering the emotional state
- “I feel ‘afraid’ because I run from the bear; I do not run because I feel afraid”
PIC2What type of responses do we associate with emotion?
3 basic classes:
- visual
- tactile/touch, pain system
- auditory
- these go to the hypothalamus and brain stem where the effector system is in the brain, where output is coordinated, the response to the inputs
PIC2What 3 system drive the response to emotional stimuli?
- can break it up into systems that are all activated by the brain stem and particularly the hypothalamus: Somatic, autonomic and endocrine
- skeletal muscle:-such as freezing, part of the fear response
- see coordinated responses from the autonomic nervous sytstems, compliment the skeletal behaviour
- and endocrine systems, activation of the pituitary
- different type of emotions are associated with different patterns in responses of the skeletal, autonomic and endocrine systems
What is the Cannon-Bard theory?
- shown the involvement of the hypothalamus in emotion, identified hypothalamus as key in outward signs of emotions
- ability to show outside signs of emotion are based on the hypothalamus, and the brain stem in general
- 1928: looked at rage responses in cats, transecting brain above hypothalamus reveals sham rage
- Lost following transection below hypothalamus
- Hess: more experiments, electrical stimulation of hypothalamic sites produces rage responses in cats
PIC3What does the hypothalamus do in emotion?
-early idea
- Hypothalamus evaluates emotional significance of external stimuli, with the resulting appraisal determining emotional reactions
- hypothalamus produces responses without cortical input
- information goes to the cortex from the hypothalamus to cause emotional states
What is the limbic system?
-the emotional circuitry
-Papez (1937) inserted
anterior thalamus and cingulate cortex circuit between hypothalamus and sensory cortex forming a loop
-involves old parts of the brain (evolutionarily)
-include cortical structures but not neocortex, only old cortex (hippocampus and amygdala)
-
PIC4What happens when you remove temporal lobes in monkeys?
Klüver & Bucy (1930s)
Behavioural deficits in monkeys after removing temporal lobes
e.g. loss of fear of snakes (basis of Klüver-Bucy
syndrome= cannot detect emotion in people an dcannot express it)
-normally have innate fear of snakes
PIC5What is in this picture:
- in blue have the limbic lobes
- major pathways connecting the parts of the limbic circuitry
- pathways: 1.ventral amygdalofugal pathway= away from amygdala
2. median forebrain bundle= descending into the brani stem
3. Dorsal longitudinal fasciculus= descending into the brain stem
4. stria terminalis= from amygdala as well
PIC6What is this?
Papez circuit
- how emotions work
- a loop = “limbic loop”
