Emotion and motivation Flashcards
What is the lateral hypothalamus?
Nucleus in the hypothalamus which when stimulated makes us eat
What is the ventromedial nucleus?
Nucleus in the hypothalamus which when stimulated suppresses eating
Which neuropeptide transmitters cause eating behaviour?
- Orexin
- MCH
Which nucleus of the hypothalamus causes eating behaviour when stimulated?
Lateral hypothalamus
Which nucleus of the hypothalamus suppresses eating behaviour when stimulated? (2)
- Ventromedial nucleus
- Paraventricular nucleus
What is leptin?
Hormone produced by fat tissue which then reduces body fat
What is released from the lateral hypothalamus to cause eating behaviour? (2)
- Orexin
- MCH
Which neuropeptides are released by satiety neurons in the arcuate nucleus? (3)
- POMC
- Alpha MSH
- CART
Which neuropeptides are released by hunger neurons in the arcuate nucleus? (2)
- Neuropeptide Y
- AgRP
How does leptin affect eating?
- Leptin excites satiety neurons in the arcuate nucleus which inhibit the lateral hypothalamus causing less feeding
- Leptin also inhibits the hunger neurons in the arcuate nucleus as they excite the lateral hypothalamus
Which 4 nuclei in the hypothalamus are involved in eating behaviour?
- Lateral hypothalamus
- Ventromedial nucleus
- Arcuate nucleus
- Paraventricular nucleus
How is the arcuate nucleus connected to the lateral hypothalamus?
- Hunger neurons in the arcuate nucleus excite the lateral hypothalamus causing feeding
- Satiety neurons in the arcuate nucleus inhibit the lateral hypothalamus which stops feeding
How is leptin connected to the arcuate nucleus?
The neurons in the arcuate nucleus have leptin receptors so respond to levels of leptin in the blood
How does the paraventricular nucleus affect eating behaviour?
Inhibits feeding when stimulated
How is the arcuate nucleus connected to the paraventricular nucleus?
- Hunger neurons in the arcuate nucleus inhibit the paraventricular nucleus which causes feeding
- Satiety neurons in the arcuate nucleus excite the paraventricular nucleus which suppresses feeding
How does leptin increase metabolic rate?
- Leptin stimulates satiety neurons in the arcuate nucleus which activate the sympathetic nervous system, causing increased metabolic rate
- Leptin inhibits hunger neurons in the arcuate nucleus which would activate the parasympathetic nervous system and decrease metabolic rate (rest and digest)
How does the paraventricular nucleus increase metabolic rate?
- Activates the sympathetic nervous system to increase metabolic rate
- Stimulates the pituitary gland to release hormones TSH/ACTH which increase metabolic rate
Which hormones are released from the pituitary gland to increase metabolic rate? (2)
- TSH (thyroid stimulating hormone)
- ACTH (adrenocorticotropic hormone)
How does blood glucose affect eating behaviour?
- High blood glucose inhibits the lateral hypothalamus to stop eating
- High blood glucose excites the ventromedial nucleus to stop eating
What are the satiety centres of the hypothalamus? (3)
- Ventromedial nucleus
- Paraventricular nucleus
- Satiety neurons in the arcuate nucleus
What are the hunger centres of the hypothalamus? (2)
- Lateral hypothalamus
- Hunger neurons in the arcuate nucleus
How does insulin affect eating behaviour?
- Insulin excites the satiety neurons in the arcuate nucleus which inhibits the lateral hypothalamus so you stop eating
- Insulin inhibits the hunger neurons in the arcuate nucleus so they can’t excite the lateral hypothalamus
What hormone is released by cells in the stomach when it is empty?
Ghrelin
What is ghrelin?
Hormone released by stomach cells when it is empty
What does ghrelin do?
Induces hunger
How does ghrelin induce hunger?
Activates the hunger neurons in the arcuate nucleus
Where is the solitary nucleus?
Brainstem
How does the solitary nucleus affect eating behaviour?
- When the stomach is full, stretch receptors send signals to the solitary nucleus via the vagus nerve
- Solitary nucleus stimulation inhibits eating
What is CCK?
Hormone released by the intestines in response to nutrients which aids digestion by slowing the emptying of the stomach
How does CCK affect eating?
- Detected by the ENS which sends signals to the solitary nucleus via the vagus nerve
- Solitary nucleus stimulation inhibits eating
Which receptors do neuropeptides target?
Metabotropic receptors
What is the amygdala involved in?
Fear
What is the limbic system?
System involved in emotional and behavioural responses
Which areas of the brain are involved in aggression?
- Amygdala
- Signals to hypothalamus
Which area of the brain is responsible for ‘affective’ (emotional) aggression?
Medial hypothalamus
Which area of the brain is responsible for predatory aggression?
Lateral hypothalamus
What is the mesolimbic pathway?
- A dopaminergic reward pathway in the brain
- Involved in addiction
What does dopamine do?
Drives motivation
What is the orbitofrontal cortex involved in?
‘Gut feelings’
