Emotion and motivation Flashcards
What is behaviour influenced by? What can influence this?
Internal states
- Sensory input can change this
What are the 4 internal states?
Feeding
Fighting
Fleeing
Mating
How to maintain a variable at a fixed state?
Compare the current measurement with a set point
- If it is different, an error signal will produce an effector
What are the 2 structures involved in regulating hunger?
Lateral hypothalamus
Ventromedial nucleus
What does the ventromedial nucleus do when electrically stimulated?
Causes satiety by inhibiting eating
What does the lateral hypothalamus do when electrically stimulated?
Causes overeating
What is leptin released by?
Adipocytes (fat)
Where are the hypothalamic neurons stimulated by leptin found?
Arcuate nucelus
What will low leptin result in?
Stimulate hunger and feeding
Suppresses energy
Inhibits reproductive competence
What does the paraventricular nucleus stimulate? What is the effect of this stimulation?
Pituitary gland to release TSH and ACTH
And the sympathetic ns
- Effect is an increase metabolic rate
How does glucose affect hunger and satiety levels?
Hunger is suppressed
Satiety is enhanced
How is insulin affected by blood glucose levels?
When blood glucose levels rise, insulin increases
- This enhances satiety
Describe the cascade of events that occurs after eating
Neurons detect food
- Stomach changes signals
- Hormone ghrelin
- Nutrients are released into intestines which are detected by neurons
- Neurons release CCK which triggers solitary nucleus to suppress eating
What does GLP-1 do?
Suppresses appetite
Mechanism of semaglutide
Promotes insulin secretion
- Reduces appetite
Which hormone suppresses feeding behaviour?
Leptin
Which hormones stimulates appetite?
Ghrelin
Orexin
NPY
What is the location of the amygdala?
In front of the hippocampus
Function of the amygdala
Activated during fearful situations
Describe the cascade for aggression
Cerebral cortex ->
Amygdala ->
Hypothalamus ->
PAG, ventral tegmental area ->
Aggressive behaviour
What does artificial activation of VMHvl cause in a mouse?
The mouse attacks inanimate objects
- Light activated neurons
What is the expected effect of removing the amygdala?
Reduced fear
What neurons encode unexpected rewards?
Dopaminergic neurons
Function of dopamine
Drive ‘wanting’ or ‘motivation’
What is the James-Lange theory?
The environment causes a subconscious psychological response ->
The mental interpretation to physiological response causes the fear emotion
What is the Cannon-Bard theory?
Emotional experience arises from the thalamus signalling to the neocortex.
Physiological reaction arises from the thalamus signalling to the hypothesis
Sensory influences both at the same time
What is the Singer-Schachter theory?
Physiological signals are ambiguous
- Interact with cognitive interpretation of what is happening
- Integration of physiological and cognitive causes emotional experience
What is the constructivist theory?
Physiological signals, culture and experience and cognitive experience cause an emotional experience
What is the mesolimbic pathway?
The reward/addiction pathway:
- Axons from substantia nigra, in the VTA innervate the ventral striatum of the basal ganglia
