Emotion and Motivation Flashcards
how is behaviour influenced by internal states?
- internal states modulate how sensory input leads to behaviour
- sensory input modifies internal states
- internal states can directly effect behaviour, without sensory input
what are the 4 F’s?
- feeding
- fighting
- fleeing
- fucking (mating)
what is the general structure of all basic homeostatic systems?
- based on negative feedback
- energy is being controlled and sensors detect energy levels
which area of the hypothalamus is orexigenic/linked to hunger?
Lateral hypothalamus
- electrode stimulates lateral section, causes organism to eat
which area of the hypothalamus is anorexigenic/linked to satiety?
Ventromedial nucleus
- electode stimulates this section, causes animal to stop eating
what 2 peptide hormones does the lateral hypothalamus release to stimulate eating behaviour?
- orexin
2. MCH (melanin-concentrating hormone)
what is leptin?
- an anorexigenic hormone produced by fat that inhibits hunger behaviour to reduce production of more fat
- negative feedback loop: lots of body fat produces more leptin, which decreases hunger so organism eats less
- leptin increases metabolic rate so organism burns more energy to decrease body fat
what are ob/ob mutant mice?
- mice which lack leptin
- they become obese
- if an ob/ob mouse’s bloodstream is linked to the bloodstream of a normal mouse, the ob/ob mouse becomes thin again
where does leptin act?
on the arcuate nucleus
what is the action of leptin?
- activates POMC (pro-opiomelanocortin), a-MSH and CART which inhibits lateral hypothalamus so decreases hunger
- inhibits neuropeptide Y (NPY) and AgRP which usually promotes the lateral hypothalamus to increase hunger
overall, leptin inhibits eating
how does leptin affect the sympathetic and parasympathetic nervous systems?
- by activating POMC, leptin activates the sympathetic system to increase metabolic rate
- by inhibiting NPY, leptin inhibits the parasympathetic systems, which would normally decrease metabolic rate
leptin overall increases metabolic rate
what is the paraventricular nucleus?
- an anorexigenic area of the hypothalamus, activated by POMC, a-MSH and CART
- it stimulates the pituitary gland to release TSH and ACTH to increase metabolic rate
what happens when there is high blood glucose level after eating?
insulin action on glucose receptors results in:
- inhibition of hunger promoting centres (NPY and AgRP)
- activation of satiety promoting centres (POMC, a-MSH, CART)
what happens when stomach centres detect lack of fullness?
- empty stomach promotes secretion of hormone ghrelin which promotes hunger
when the stomach is full, it no longer releases ghrelin, so hunger is inhibited
what do the chemical receptors in the intestines detect?
they detect changes in nutrient concentrations
- full stomach causes high conc of nutrients in intenstines
- gut secretes CCK
- enteric neurons detect CCK and send a signal via Vagus nerve to solitary nucleus in brainstem
- solitary nucleus inhibits eating behaviour
what important role is the amygdala involved in?
fear:
- when doing fMRI, amygdala is activated when viewing fearful faces
- lesion in amygdala causes animals to show less fear
how is the amygdala involved in fear-based learning?
- electric shock paired with a sound causes animal to associate the shock with the sound
- if just the sound is played, the animal will show fear
- this fear no longer happens if the amygdala is removed
what two brain areas are important in aggression
- amygdala
2. hypothalamus
how is the amydala involved in aggression?
- if the amydala is removed from a dominant monkey, that monkey falls to the bottom of the hierarchy
- this is because they no longer show aggressive behaviours
how is the hypothalamus involved in aggression?
medial hypothalamus -> affective aggression
lateral hypothalamus -> predatory aggression
experiment: electode planted in ventrolateral subdivision of ventromedial hypothalamus
- when stimulated rat displays aggressive behaviour
experiment 2: transgenic mouse with ion channel activated by light located in the ventromedial hypothalamus becomes aggressive when light is switched on
how is dopamine involved in reward prediction error in the mesolimbic pathway?
- brain tries to predict the future to guide behaviour
- when something surprising happens, dopamine is released
experiment: monkey is rewarded with grape juice when light turns on
- monkey predicts he will get juice when light comes on
- dopaminergic neurons shift response from the reward itself to the light turning on (condition stimulus)
- APs are fired when they see the light turn on, rather than the actual reward
how does dopamine drive wanting/motivation?
- rats with destroyed mesolimbic dopaminergic neurons enjoy food, but lack motivation to seek food
- dopamine signals for something you should be motivated by, not just for happiess
- drug addiction is a disorder of motivation: motivation is for drugs rather than anything else
how does the ventromedial prefrontal cortex (orbitofrontal cortex) control gut feelings?
experiment: Deck A is low risk low reward, deck B is high risk high reward
- subjects learn to avoid deck B and show a stress response when hovering over deck B
- there is a sympathetic activation when they reach for the risky deck, causing increased sweating as they are nervous
patients with orbitofrontal lesions don’t avoid deck B and don’t show anticipatory stress when hovering over
what is the common sense ‘folk’ theory of how emotions are made?
- sensory input leads to emotional experience which causes brain to trigger a physiological reaction
what is the James-Lange theory on how emotions are made?
- sensory input leads to a physiological reaction, which then triggers an emotional experience
what is the Cannon-Bard theory of making emotions?
- emotional experience arises from thalamus signaling to neocortex
- physiological reaction arises from thalamus signalling to hypothalamus
what is the Singer-Schachter theory of emotions being made?
- an interaction between mental state and physiological reaction
- physiological reaction is amiguous (increase in HR can be due to excitement or stress)
- emotional experience is formed from a cognitive interpretation of the physiological reaction
what is the constructivist theory in how emotions ar emade?
- culture and experiences also play a part in emotional experiences
