4.9 Appetitive

Question 1

catabolic

Answer 1

releasing and using energy

Question 2

anabolic

Answer 2

acquiring and storing energy

Question 3

set point theory

Answer 3

there is a preferred body weight that the brain defends

Question 4

orexigenic

Answer 4

substances/signals that stimulate hunger, increase food intake

Question 5

anorexigenic

Answer 5

substances/signals that suppress hunger, decrease food intake

Question 6

function of nucleus of solitary tract

Answer 6

integrates visceral sensory information related to hunger/satiety

Question 7

outline leptin

Answer 7

anorexigenic
Hormone produced by adipose tissue (fat cells) in proportion to body fat stores → the more fat cells you have, the more leptin you produce, starts to slow down how much you eat (it’s a way for your brain to know if you have enough body fat)

Question 8

outline insulin

Answer 8

anorexigenic
Hormone released by pancreas in response to rising blood glucose levels after a meal
Signals the brain (hypothalamus) about energy availability
Acts on arcuate nucleus

Question 9

outline ghrelin

Answer 9

orexigenic
Hormone released from stomach when empty
Inject w ghrelin = people feel hungry
Activates reward pathways

Question 10

GLP-1 - glucagon-like peptide

Answer 10

Oregixenic
Hormone released by small intensive in response to food, esp carbs + fats
Satiety signal,
Slows gastric emptying, stimulates insulin release to aid glucose regulation, acts on hypothalamus and brainstem to promote feelings of fulness
Semaglutide

Question 11

explain how ghrelin acts on brain

Answer 11

Ghrelin: comes in through stomach, causes arcuate nucleus to stimulate the lateral hypothalamus and inhibit PVN, increasing appetite

Question 12

explain how leptin, GLP-1, insulin act on brain

Answer 12

cause arcuate nucleus to inhibit lateral hypothalamus and stimulate PVN, decreasing appetite

Question 13

what does PVN do when it’s hungry

Answer 13

activates pituitary gland (starts HPA axis), fight or flight into medulla → autonomic nervous system

Question 14

what does LH do when it’s full

Answer 14

sends rest/digest to medulla → autonomic nervous system

Question 15

outline missed lunch effect (subjective state of hunger)

Answer 15

Subjective state of hunger not always tied to body’s need for energy or how long it’s been since we’ve eaten → more tied to time of day/when we typically get hungry

Question 16

outline Weingarten’s experiment on external cues role in appetite. what does it indicate overall?

Answer 16

rats given food + CS together randomly throughout day

given free access to food but exposed to CS for 2 minutes

eat 20% pf daily caloric intake during those 2 minutes

Huge amount of eating behaviour is tied to conditioning, not energy needs

Question 17

what causes dopamine release, in relation to food?

Answer 17

Conditioned stimuli, NOT FOOD

Question 18

homeostatic signals

Answer 18

internal, energy-driven signals involving PVN –> leptin, insulin (stimulating PVN, inhibiting ARC), ghrelin (inhibits PVN, stimulates ARC)

Question 19

hedonic signals

Answer 19

external, reward-driven signals involving VTA, NAc, cortex –> external signals → processes of mesolimbocortical dopamine and appetite

Question 20

role of striatum in food-relevant cues

Answer 20

dopamine centre → learning and behaviour

Question 21

role of amygdala in food-relevant cues

Answer 21

affective response, assigns emotional value (valence) to food-related stimuli

Question 22

role of orbitofrontal cortex in food-relevant cues

Answer 22

adjusts stimuli reward and value relative to emotional state

Question 23

role of insula cortex in food-relevant cues

Answer 23

receives taste information and internal body states

Question 24

explain the role of the orbitofrontal cortex (OFC) in eating

Answer 24

evaluation of food-related rewards, determines appeal of food, decisions about eating: whether to continue (based on palatability) or stop (based on lower reward with continued consumption)

Question 25

outline the stimulu-specific satiety BANANA experiment

Answer 25

Before eating, banana odour activated the OFC strongly (i.e. rewarding) After eating as many bananas as they liked, the same banana odour when presented during a scan produced much less OFC activity Vanilla didn’t change much Shows: brain reduces the reward value of a just-consumed food → reward value is encoded relative to motivational state

Question 26

what is the effect of placebo pleasantness?

Answer 26

descriptions of food as “rich”, “fresh”, “delicious” is associated with higher activity in OFC

Question 27

outline experiment explaining how Highly palatable foods disguise effect of satiety:

Answer 27

Soup is refilled through a tube, and participants are unknowingly given a carb or fat preload (i.e. to ensure they’re not hungry) Participants are more of the palatable lunch regardless of how much energy they had already consumed, whereas normally after a high-energy preload people eat less at the next meal

Question 28

changes to WHICH type of mechanisms are most closely associated with obesity?

Answer 28

hedonic

Question 29

3 big changes in regulation in obesity"

Answer 29

Reduced susceptibility to internal satiety signals Reduced dopamine regulation Highly susceptible to external sensory cues and food palatability

Question 30

higher BMI is correlated with lower what receptor

Answer 30

D2

Question 31

similarities between obesity and addiction: both include...

Answer 31

dopamine involvement, reward system activation, cue-induced craving, compulsive behaviour, neuroadaptation → NAc strengthens salience of stimuli and decreases self-regulation

Question 32

what does GLP-1 do for addiction?

Answer 32

reduce addictive behaviour for drugs of abuse, addiction

Question 33

how does (simply) GLP-1 work for addiction?

Answer 33

Targets nucleus accumbens and VTA to dampen dopamine release, making the drug/food feel less rewarding